The Importance of Isomorphism for Conclusions about Homology: A Bayesian Multilevel Structural Equation Modeling Approach with Ordinal Indicators.

PubMed

Guenole, Nigel

2016-01-01

We describe a Monte Carlo study examining the impact of assuming item isomorphism (i.e., equivalent construct meaning across levels of analysis) on conclusions about homology (i.e., equivalent structural relations across levels of analysis) under varying degrees of non-isomorphism in the context of ordinal indicator multilevel structural equation models (MSEMs). We focus on the condition where one or more loadings are higher on the between level than on the within level to show that while much past research on homology has ignored the issue of psychometric isomorphism, psychometric isomorphism is in fact critical to valid conclusions about homology. More specifically, when a measurement model with non-isomorphic items occupies an exogenous position in a multilevel structural model and the non-isomorphism of these items is not modeled, the within level exogenous latent variance is under-estimated leading to over-estimation of the within level structural coefficient, while the between level exogenous latent variance is overestimated leading to underestimation of the between structural coefficient. When a measurement model with non-isomorphic items occupies an endogenous position in a multilevel structural model and the non-isomorphism of these items is not modeled, the endogenous within level latent variance is under-estimated leading to under-estimation of the within level structural coefficient while the endogenous between level latent variance is over-estimated leading to over-estimation of the between level structural coefficient. The innovative aspect of this article is demonstrating that even minor violations of psychometric isomorphism render claims of homology untenable. We also show that posterior predictive p-values for ordinal indicator Bayesian MSEMs are insensitive to violations of isomorphism even when they lead to severely biased within and between level structural parameters. We highlight conditions where poor estimation of even correctly specified

The Importance of Isomorphism for Conclusions about Homology: A Bayesian Multilevel Structural Equation Modeling Approach with Ordinal Indicators

PubMed Central

Guenole, Nigel

2016-01-01

We describe a Monte Carlo study examining the impact of assuming item isomorphism (i.e., equivalent construct meaning across levels of analysis) on conclusions about homology (i.e., equivalent structural relations across levels of analysis) under varying degrees of non-isomorphism in the context of ordinal indicator multilevel structural equation models (MSEMs). We focus on the condition where one or more loadings are higher on the between level than on the within level to show that while much past research on homology has ignored the issue of psychometric isomorphism, psychometric isomorphism is in fact critical to valid conclusions about homology. More specifically, when a measurement model with non-isomorphic items occupies an exogenous position in a multilevel structural model and the non-isomorphism of these items is not modeled, the within level exogenous latent variance is under-estimated leading to over-estimation of the within level structural coefficient, while the between level exogenous latent variance is overestimated leading to underestimation of the between structural coefficient. When a measurement model with non-isomorphic items occupies an endogenous position in a multilevel structural model and the non-isomorphism of these items is not modeled, the endogenous within level latent variance is under-estimated leading to under-estimation of the within level structural coefficient while the endogenous between level latent variance is over-estimated leading to over-estimation of the between level structural coefficient. The innovative aspect of this article is demonstrating that even minor violations of psychometric isomorphism render claims of homology untenable. We also show that posterior predictive p-values for ordinal indicator Bayesian MSEMs are insensitive to violations of isomorphism even when they lead to severely biased within and between level structural parameters. We highlight conditions where poor estimation of even correctly specified

MAJORANA Collaboration's experience with germanium detectors

DOE PAGES

Mertens, S.; Abgrall, N.; Avignone, F. T.; ...

2015-05-01

The goal of the Majorana Demonstrator project is to search for 0νββ decay in 76Ge. Of all candidate isotopes for 0νββ, 76Ge has some of the most favorable characteristics. Germanium detectors are a well established technology, and in searches for 0νββ, the high purity germanium crystal acts simultaneously as source and detector. Furthermore, p-type germanium detectors provide excellent energy resolution and a specially designed point contact geometry allows for sensitive pulse shape discrimination. This paper will summarize the experiences the MAJORANA collaboration made with enriched germanium detectors manufactured by ORTEC®®. The process from production, to characterization and integration in MAJORANAmore » mounting structure will be described. A summary of the performance of all enriched germanium detectors will be given.« less

Isomorphism and solid solutions among Ag- and Au-selenides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palyanova, Galina A.; Seryotkin, Yurii V.; Novosibirsk State University

Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag{sub 2−x}Au{sub x}Se with a step of x=0.25 (0≤x≤2) to 1050 °C and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag{sub 2}Se – Ag{sub 1.94}Au{sub 0.06}Se, fischesserite Ag{sub 3}AuSe{sub 2} - Ag{sub 3.2}Au{sub 0.8}Se{sub 2} and gold selenide AuSe - Au{sub 0.94}Ag{sub 0.06}Se. Solid solutions and AgAuSe phases were added tomore » the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe. - Highlights: • Au-Ag selenides were synthesized. • Limited Ag-Au isomorphism in the selenides is affected by structural features. • Some new phases were introduced to the phase diagram Ag-Au-Se.« less

Slow Crack Growth of Germanium

NASA Technical Reports Server (NTRS)

Salem, Jon

2016-01-01

The fracture toughness and slow crack growth parameters of germanium supplied as single crystal beams and coarse grain disks were measured. Although germanium is anisotropic (A=1.7), it is not as anisotropic as SiC, NiAl, or Cu, as evidence by consistent fracture toughness on the 100, 110, and 111 planes. Germanium does not exhibit significant slow crack growth in distilled water. (n=100). Practical values for engineering design are a fracture toughness of 0.7 MPam and a Weibull modulus of m=6+/-2. For well ground and reasonable handled coupons, fracture strength should be greater than 30 MPa.

Germanium: From Its Discovery to SiGe Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haller, E.E.

2006-06-14

Germanium, element No.32, was discovered in 1886 by Clemens Winkler. Its first broad application was in the form of point contact Schottky diodes for radar reception during WWII. The addition of a closely spaced second contact led to the first all-solid-state electronic amplifier device, the transistor. The relatively low bandgap, the lack of a stable oxide and large surface state densities relegated germanium to the number 2 position behind silicon. The discovery of the lithium drift process, which made possible the formation of p-i-n diodes with fully depletable i-regions several centimeters thick, led germanium to new prominence as the premiermore » gamma-ray detector. The development of ultra-pure germanium yielded highly stable detectors which have remained unsurpassed in their performance. New acceptors and donors were discovered and the electrically active role of hydrogen was clearly established several years before similar findings in silicon. Lightly doped germanium has found applications as far infrared detectors and heavily Neutron Transmutation Doped (NTD) germanium is used in thermistor devices operating at a few milliKelvin. Recently germanium has been rediscovered by the silicon device community because of its superior electron and hole mobility and its ability to induce strains when alloyed with silicon. Germanium is again a mainstream electronic material.« less

Epitaxial Deposition Of Germanium Doped With Gallium

NASA Technical Reports Server (NTRS)

Huffman, James E.

1994-01-01

Epitaxial layers of germanium doped with gallium made by chemical vapor deposition. Method involves combination of techniques and materials used in chemical vapor deposition with GeH4 or GeCl4 as source of germanium and GaCl3 as source of gallium. Resulting epitaxial layers of germanium doped with gallium expected to be highly pure, with high crystalline quality. High-quality material useful in infrared sensors.

Method of fabricating germanium and gallium arsenide devices

NASA Technical Reports Server (NTRS)

Jhabvala, Murzban (Inventor)

1990-01-01

A method of semiconductor diode fabrication is disclosed which relies on the epitaxial growth of a precisely doped thickness layer of gallium arsenide or germanium on a semi-insulating or intrinsic substrate, respectively, of gallium arsenide or germanium by either molecular beam epitaxy (MBE) or by metal-organic chemical vapor deposition (MOCVD). The method involves: depositing a layer of doped or undoped silicon dioxide on a germanium or gallium arsenide wafer or substrate, selectively removing the silicon dioxide layer to define one or more surface regions for a device to be fabricated thereon, growing a matched epitaxial layer of doped germanium or gallium arsenide of an appropriate thickness using MBE or MOCVD techniques on both the silicon dioxide layer and the defined one or more regions; and etching the silicon dioxide and the epitaxial material on top of the silicon dioxide to leave a matched epitaxial layer of germanium or gallium arsenide on the germanium or gallium arsenide substrate, respectively, and upon which a field effect device can thereafter be formed.

Recovery of germanium-68 from irradiated targets

DOEpatents

Phillips, Dennis R.; Jamriska, Sr., David J.; Hamilton, Virginia T.

1993-01-01

A process for selective separation of germanium-68 from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, contacting the first ion-containing solution with a cationic resin whereby ions selected from the group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in a second ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the first resin, adjusting the pH of the second ion-containing solution to within a range of from about 0.7 to about 3.0, adjusting the soluble metal halide concentration in the second ion-containing solution to a level adapted for subsequent separation of germanium, contacting the pH-adjusted, soluble metal halide-containing second ion-containing solution with a dextran-based material whereby germanium ions are separated by the dextran-based material, and recovering the germanium from the dextran-based material, preferably by distillation.

Germanium resistance thermometer calibration at superfluid helium temperatures

NASA Technical Reports Server (NTRS)

Mason, F. C.

1985-01-01

The rapid increase in resistance of high purity semi-conducting germanium with decreasing temperature in the superfluid helium range of temperatures makes this material highly adaptable as a very sensitive thermometer. Also, a germanium thermometer exhibits a highly reproducible resistance versus temperature characteristic curve upon cycling between liquid helium temperatures and room temperature. These two factors combine to make germanium thermometers ideally suited for measuring temperatures in many cryogenic studies at superfluid helium temperatures. One disadvantage, however, is the relatively high cost of calibrated germanium thermometers. In space helium cryogenic systems, many such thermometers are often required, leading to a high cost for calibrated thermometers. The construction of a thermometer calibration cryostat and probe which will allow for calibrating six germanium thermometers at one time, thus effecting substantial savings in the purchase of thermometers is considered.

Homology and isomorphism: Bourdieu in conversation with New Institutionalism.

PubMed

Wang, Yingyao

2016-06-01

Bourdieusian Field Theory (BFT) provided decisive inspiration for the early conceptual formulation of New Institutionalism (NI). This paper attempts to reinvigorate the stalled intellectual dialogue between NI and BFT by comparing NI's concept of isomorphism with BFT's notion of homology. I argue that Bourdieu's understanding of domination-oriented social action, transposable habitus, and a non-linear causality, embodied in his neglected concept of homology, provides an alternative theorization of field-level convergence to New Institutionalism's central idea of institutional isomorphism. To showcase how BFT can be useful for organizational research, I postulate a habitus-informed and field-conditioned theory of transference to enrich NI's spin-off thesis of 'diffusion'. I propose that while NI can benefit from BFT's potential of bringing social structure back into organizational research, BFT can enrich its social analysis by borrowing from NI's elaboration of the symbolic system of organizations. © London School of Economics and Political Science 2016.

Isomorphism and solid solutions among Ag- and Au-selenides

NASA Astrophysics Data System (ADS)

Palyanova, Galina A.; Seryotkin, Yurii V.; Kokh, Konstantin A.; Bakakin, Vladimir V.

2016-09-01

Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag2-xAuxSe with a step of х=0.25 (0≤х≤2) to 1050 °С and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag2Se - Ag1.94Au0.06Se, fischesserite Ag3AuSe2 - Ag3.2Au0.8Se2 and gold selenide AuSe - Au0.94Ag0.06Se. Solid solutions and AgAuSe phases were added to the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe.

Electronic considerations for externally segmented germanium detectors

NASA Technical Reports Server (NTRS)

Madden, N. W.; Landis, D. A.; Goulding, F. S.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Malone, D. F.; Pollard, M. J.

1991-01-01

The dominant background source for germanium gamma ray detector spectrometers used for some astrophysics observations is internal beta decay. Externally segmented germanium gamma ray coaxial detectors can identify beta decay by localizing the event. Energetic gamma rays interact in the germanium detector by multiple Compton interactions while beta decay is a local process. In order to recognize the difference between gamma rays and beta decay events, the external electrode (outside of detector) is electrically partitioned. The instrumentation of these external segments and the consequence with respect to the spectrometer energy signal is examined.

Front End Spectroscopy ASIC for Germanium Detectors

NASA Astrophysics Data System (ADS)

Wulf, Eric

Large-area, tracking, semiconductor detectors with excellent spatial and spectral resolution enable exciting new access to soft (0.2-5 MeV) gamma-ray astrophysics. The improvements from semiconductor tracking detectors come with the burden of high density of strips and/or pixels that require high-density, low-power, spectroscopy quality readout electronics. CMOS ASIC technologies are a natural fit to this requirement and have led to high-quality readout systems for all current semiconducting tracking detectors except for germanium detectors. The Compton Spectrometer and Imager (COSI), formerly NCT, at University of California Berkeley and the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) at Goddard Space Flight Center utilize germanium cross-strip detectors and are on the forefront of NASA's Compton telescope research with funded missions of long duration balloon flights. The development of a readout ASIC for germanium detectors would allow COSI to replace their discrete electronics readout and would enable the proposed Gamma-Ray Explorer (GRX) mission utilizing germanium strip-detectors. We propose a 3-year program to develop and test a germanium readout ASIC to TRL 5 and to integrate the ASIC readout onto a COSI detector allowing a TRL 6 demonstration for the following COSI balloon flight. Our group at NRL led a program, sponsored by another government agency, to produce and integrate a cross-strip silicon detector ASIC, designed and fabricated by Dr. De Geronimo at Brookhaven National Laboratory. The ASIC was designed to handle the large (>30 pF) capacitance of three 10 cm^2 detectors daisy-chained together. The front-end preamplifier, selectable inverter, shaping times, and gains make this ASIC compatible with a germanium cross-strip detector as well. We therefore have the opportunity and expertise to leverage the previous investment in the silicon ASIC for a new mission. A germanium strip detector ASIC will also require precise timing of the signals at

A mechanism of institutional isomorphism in referral networks among hospitals in Seoul, South Korea.

PubMed

Jung, Minsoo; Choi, Mankyu

2010-01-01

Hospitals engage in medical referral system relations voluntarily, by virtue of their own service capacities. These capacities include medical technology, equipment supply, and patient management, which are assessed individually by medical institutions in efforts to control costs and maintain efficiency in tertiary hospitals. This study assessed referral networks according to the institutional isomorphism theory of new economic sociology. As a result, the referral networks were shown to exhibit emergent structural hierarchy via cumulative clustering by established year and were not affected by attributive variables such as region, bed number, and year of establishment. In particular, the networks evidenced institutional isomorphism with certain central hospitals. As a consequence, personal indices were shown to decrease in accordance with its period, and only the structural index increased. Normative pressures cause organizations to become hierarchically homogenized, in accordance with the principle of organizational learning in specialized fields. Therefore, normative isomorphism on the basis of public domains should be considered an inherent factor in the development of referral networks.

Isomorphic red blood cells using automated urine flow cytometry is a reliable method in diagnosis of bladder cancer.

PubMed

Muto, Satoru; Sugiura, Syo-Ichiro; Nakajima, Akiko; Horiuchi, Akira; Inoue, Masahiro; Saito, Keisuke; Isotani, Shuji; Yamaguchi, Raizo; Ide, Hisamitsu; Horie, Shigeo

2014-10-01

We aimed to identify patients with a chief complaint of hematuria who could safely avoid unnecessary radiation and instrumentation in the diagnosis of bladder cancer (BC), using automated urine flow cytometry to detect isomorphic red blood cells (RBCs) in urine. We acquired urine samples from 134 patients over the age of 35 years with a chief complaint of hematuria and a positive urine occult blood test or microhematuria. The data were analyzed using the UF-1000i (®) (Sysmex Co., Ltd., Kobe, Japan) automated urine flow cytometer to determine RBC morphology, which was classified as isomorphic or dysmorphic. The patients were divided into two groups (BC versus non-BC) for statistical analysis. Multivariate logistic regression analysis was used to determine the predictive value of flow cytometry versus urine cytology, the bladder tumor antigen test, occult blood in urine test, and microhematuria test. BC was confirmed in 26 of 134 patients (19.4 %). The area under the curve for RBC count using the automated urine flow cytometer was 0.94, representing the highest reference value obtained in this study. Isomorphic RBCs were detected in all patients in the BC group. On multivariate logistic regression analysis, only isomorphic RBC morphology was significantly predictive for BC (p < 0.001). Analytical parameters such as sensitivity, specificity, positive predictive value, and negative predictive value of isomorphic RBCs in urine were 100.0, 91.7, 74.3, and 100.0 %, respectively. Detection of urinary isomorphic RBCs using automated urine flow cytometry is a reliable method in the diagnosis of BC with hematuria.

Mineral resource of the month: germanium

USGS Publications Warehouse

Jorgenson, John D.

2003-01-01

Germanium is a hard, brittle semimetal that first came into use over a half-century ago as a semiconductor material in radar units and in the first transistor ever made. Most germanium is recovered as a byproduct of zinc smelting, but it has also been recovered at some copper smelters and from the fly ash of coal-burning industrial power plants.

Institutional Isomorphism and the Creation of the Unified National System of Higher Education in Australia: An Empirical Analysis

ERIC Educational Resources Information Center

Croucher, Gwilym; Woelert, Peter

2016-01-01

Previous research has highlighted the occurrence of isomorphic tendencies--convergences in terms of formal organizational structure--in higher education systems in times of uncertainty and under external pressure to change. It has been repeatedly claimed that the Australian university system largely followed a logic of isomorphic change in the…

All-inorganic Germanium nanocrystal films by cationic ligand exchange

DOE PAGES

Wheeler, Lance M.; Nichols, Asa W.; Chernomordik, Boris D.; ...

2016-01-21

In this study, we introduce a new paradigm for group IV nanocrystal surface chemistry based on room temperature surface activation that enables ionic ligand exchange. Germanium nanocrystals synthesized in a gas-phase plasma reactor are functionalized with labile, cationic alkylammonium ligands rather than with traditional covalently bound groups. We employ Fourier transform infrared and 1H nuclear magnetic resonance spectroscopies to demonstrate the alkylammonium ligands are freely exchanged on the germanium nanocrystal surface with a variety of cationic ligands, including short inorganic ligands such as ammonium and alkali metal cations. This ionic ligand exchange chemistry is used to demonstrate enhanced transport inmore » germanium nanocrystal films following ligand exchange as well as the first photovoltaic device based on an all-inorganic germanium nanocrystal absorber layer cast from solution. This new ligand chemistry should accelerate progress in utilizing germanium and other group IV nanocrystals for optoelectronic applications.« less

Crystal growth of HVPE-GaN doped with germanium

NASA Astrophysics Data System (ADS)

Iwinska, M.; Takekawa, N.; Ivanov, V. Yu.; Amilusik, M.; Kruszewski, P.; Piotrzkowski, R.; Litwin-Staszewska, E.; Lucznik, B.; Fijalkowski, M.; Sochacki, T.; Teisseyre, H.; Murakami, H.; Bockowski, M.

2017-12-01

Crystallization by hydride vapor phase epitaxy method of gallium nitride single crystals doped with germanium and properties of the obtained material are described in this paper. Growth was performed in hydrogen and nitrogen carrier gas. The results were studied and compared. Influence of different flows of germanium tetrachloride, precursor of germanium, on the grown crystals was investigated. Ammonothermal GaN substrates were used as seeds for crystallization. Structural, electrical, and optical properties of HVPE-GaN doped with germanium are presented and discussed in detail. They were compared to properties of HVPE-GaN doped with silicon and also grown on native seeds of high quality.

Germanium soup

NASA Astrophysics Data System (ADS)

Palmer, Troy A.; Alexay, Christopher C.

2006-05-01

This paper addresses the variety and impact of dispersive model variations for infrared materials and, in particular, the level to which certain optical designs are affected by this potential variation in germanium. This work offers a method for anticipating and/or minimizing the pitfalls such potential model variations may have on a candidate optical design.

Germanium Resistance Thermometer For Subkelvin Temperatures

NASA Technical Reports Server (NTRS)

Castles, Stephen H.

1993-01-01

Improved germanium resistance thermometer measures temperatures as small as 0.01 K accurately. Design provides large area for electrical connections (to reduce electrical gradients and increase sensitivity to changes in temperatures) and large heat sink (to minimize resistance heating). Gold pads on top and bottom of germanium crystal distribute electrical current and flow of heat nearly uniformly across crystal. Less expensive than magnetic thermometers or superconducting quantum interference devices (SQUID's) otherwise used.

Structural Design Parameters for Germanium

NASA Technical Reports Server (NTRS)

Salem, Jon; Rogers, Richard; Baker, Eric

2017-01-01

The fracture toughness and slow crack growth parameters of germanium supplied as single crystal beams and coarse grain disks were measured. Although germanium is anisotropic (A* 1.7), it is not as anisotropic as SiC, NiAl, or Cu. Thus the fracture toughness was similar on the 100, 110, and 111 planes, however, measurements associated with randomly oriented grinding cracks were 6 to 30 higher. Crack extension in ring loaded disks occurred on the 111 planes due to both the lower fracture energy and the higher stresses on stiff 111 planes. Germanium exhibits a Weibull scale effect, but does not exhibit significant slow crack growth in distilled water. (n 100), implying that design for quasi static loading can be performed with scaled strength statistics. Practical values for engineering design are a fracture toughness of 0.69 0.02 MPam (megapascals per square root meter) and a Weibull modulus of m 6 2. For well ground and reasonable handled coupons, average fracture strength should be greater than 40 megapascals. Aggregate, polycrystalline elastic constants are Epoly 131 gigapascals, vpoly 0.22.

Simple nuclear C*-algebras not isomorphic to their opposites

PubMed Central

Hirshberg, Ilan

2017-01-01

We show that it is consistent with Zermelo–Fraenkel set theory with the axiom of choice (ZFC) that there is a simple nuclear nonseparable C∗-algebra, which is not isomorphic to its opposite algebra. We can furthermore guarantee that this example is an inductive limit of unital copies of the Cuntz algebra O2 or of the canonical anticommutation relations (CAR) algebra. PMID:28559339

The germination of germanium

NASA Astrophysics Data System (ADS)

Burdette, Shawn C.; Thornton, Brett F.

2018-02-01

Shawn C. Burdette and Brett F. Thornton explore how germanium developed from a missing element in Mendeleev's periodic table to an enabler for the information age, while retaining a nomenclature oddity.

Extrinsic germanium Blocked Impurity Bank (BIB) detectors

NASA Technical Reports Server (NTRS)

Krabach, Timothy N.; Huffman, James E.; Watson, Dan M.

1989-01-01

Ge:Ga blocked-impurity-band (BIB) detectors with long wavelength thresholds greater than 190 microns and peak quantum efficiencies of 4 percent, at an operating temperature of 1.8 K, have been fabricated. These proof of concept devices consist of a high purity germanium blocking layer epitaxially grown on a Ga-doped Ge substrate. This demonstration of BIB behavior in germanium enables the development of far infrared detector arrays similar to the current silicon-based devices. Present efforts are focussed on improving the chemical vapor deposition process used to create the blocking layer and on the lithographic processing required to produce monolithic detector arrays in germanium. Approaches to test the impurity levels in both the blocking and active layers are considered.

Hypnosis in sport: an Isomorphic Model.

PubMed

Robazza, C; Bortoli, L

1994-10-01

Hypnosis in sport can be applied according to an Isomorphic Model. Active-alert hypnosis is induced before or during practice whereas traditional hypnosis is induced after practice to establish connections between the two experiences. The fundamental goals are to (a) develop mental skills important to both motor and hypnotic performance, (b) supply a wide range of motor and hypnotic bodily experiences important to performance, and (c) induce alert hypnosis before or during performance. The model is based on the assumption that hypnosis and motor performance share common skills modifiable through training. Similarities between hypnosis and peak performance in the model are also considered. Some predictions are important from theoretical and practical points of view.

Bottom-up assembly of metallic germanium.

PubMed

Scappucci, Giordano; Klesse, Wolfgang M; Yeoh, LaReine A; Carter, Damien J; Warschkow, Oliver; Marks, Nigel A; Jaeger, David L; Capellini, Giovanni; Simmons, Michelle Y; Hamilton, Alexander R

2015-08-10

Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers, and a plasmonic conductor for bio-sensing. Common to these diverse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (10(19) to 10(20) cm(-3)) low-resistivity (10(-4)Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography, and density functional theory.

Bottom-up assembly of metallic germanium

NASA Astrophysics Data System (ADS)

Scappucci, Giordano; Klesse, Wolfgang M.; Yeoh, Lareine A.; Carter, Damien J.; Warschkow, Oliver; Marks, Nigel A.; Jaeger, David L.; Capellini, Giovanni; Simmons, Michelle Y.; Hamilton, Alexander R.

2015-08-01

Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers, and a plasmonic conductor for bio-sensing. Common to these diverse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (1019 to 1020 cm-3) low-resistivity (10-4Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography, and density functional theory.

Isomorphisms between Petri nets and dataflow graphs

NASA Technical Reports Server (NTRS)

Kavi, Krishna M.; Buckles, Billy P.; Bhat, U. Narayan

1987-01-01

Dataflow graphs are a generalized model of computation. Uninterpreted dataflow graphs with nondeterminism resolved via probabilities are shown to be isomorphic to a class of Petri nets known as free choice nets. Petri net analysis methods are readily available in the literature and this result makes those methods accessible to dataflow research. Nevertheless, combinatorial explosion can render Petri net analysis inoperative. Using a previously known technique for decomposing free choice nets into smaller components, it is demonstrated that, in principle, it is possible to determine aspects of the overall behavior from the particular behavior of components.

Neutron-transmutation-doped germanium bolometers

NASA Technical Reports Server (NTRS)

Palaio, N. P.; Rodder, M.; Haller, E. E.; Kreysa, E.

1983-01-01

Six slices of ultra-pure germanium were irradiated with thermal neutron fluences between 7.5 x 10 to the 16th and 1.88 x 10 to the 18th per sq cm. After thermal annealing the resistivity was measured down to low temperatures (less than 4.2 K) and found to follow the relationship rho = rho sub 0 exp(Delta/T) in the hopping conduction regime. Also, several junction FETs were tested for noise performance at room temperature and in an insulating housing in a 4.2 K cryostat. These FETs will be used as first stage amplifiers for neutron-transmutation-doped germanium bolometers.

Optimal seasonal schedules and the relative dominance of heteromorphic and isomorphic life cycles in macroalgae.

PubMed

Bessho, Kazuhiro; Iwasa, Yoh

2010-11-21

Marine macroalgae (seaweed) show diverse life cycles. Species with a heteromorphic life cycle have a large multicellular algal body in one generation but have a very small body in the second generation of the same year. In contrast, the diploid and haploid life forms of isomorphic species have similar morphology, and these species often have more than two generations in a year. Here, we first study the optimal life cycle schedule of marine macroalgae when daily mortality changes seasonally, and then we discuss the conditions for coexistence and relative dominance of different life cycles. According to the optimal life cycle schedule, heteromorphic species tend to have a generation with a large algal body when mortality is low, and a microscopic-sized generation when mortality is high. In contrast, isomorphic species tend to mature when body size reaches a threshold value that is the same for different generations. We then examine the coexistence of the two life cycles when growth rate decreases with biomass. The model predicts that (1) at high latitudes (i.e., in strongly seasonal environments), heteromorphic species are likely to dominate over isomorphic species, and (2) species with a heteromorphic life cycle should dominate in the supratidal and upper intertidal zones where macroalgae tend to suffer high mortality, and also in the subtidal zone, where mortality is low, whereas isomorphic species are likely to be more successful when mortality is intermediate. These predictions are consistent with the observed distribution patterns of the two life cycles in macroalgae. Copyright © 2010 Elsevier Ltd. All rights reserved.

Assessing Student Expertise in Introductory Physics with Isomorphic Problems. II. Effect of Some Potential Factors on Problem Solving and Transfer

ERIC Educational Resources Information Center

Chandralekha; Singh

2008-01-01

In this paper, we explore the use of isomorphic problem pairs (IPPs) to assess introductory physics students' ability to solve and successfully transfer problem-solving knowledge from one context to another in mechanics. We call the paired problems "isomorphic" because they require the same physics principle to solve them. We analyze written…

'You'll See That Everywhere': Institutional Isomorphism in Secondary School Subject Departments

ERIC Educational Resources Information Center

Puttick, Steven

2017-01-01

This paper asks why spatially separated school departments might exhibit, in different ways, very similar practices. Data from an ethnographic study of three secondary school geography departments in England are discussed through a concept of "isomorphism" (homogenising forces), drawn from neo-institutional theory. Similarities across…

Near-infrared emission from mesoporous crystalline germanium

NASA Astrophysics Data System (ADS)

Boucherif, Abderraouf; Korinek, Andreas; Aimez, Vincent; Arès, Richard

2014-10-01

Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

Delay discounting of food by rhesus monkeys: Cocaine and food choice in isomorphic and allomorphic situations.

PubMed

Huskinson, Sally L; Woolverton, William L; Green, Leonard; Myerson, Joel; Freeman, Kevin B

2015-06-01

Research on delay discounting has focused largely on nondrug reinforcers in an isomorphic context in which choice is between alternatives that involve the same type of reinforcer. Less often, delay discounting has been studied with drug reinforcers in a more ecologically valid allomorphic context where choice is between alternatives involving different types of reinforcers. The present experiment is the first to examine discounting of drug and nondrug reinforcers in both isomorphic and allomorphic situations using a theoretical model (i.e., the hyperbolic discounting function) that allows for comparisons of discounting rates between reinforcer types and amounts. The goal of the current experiment was to examine discounting of a delayed, nondrug reinforcer (food) by male rhesus monkeys when the immediate alternative was either food (isomorphic situation) or cocaine (allomorphic situation). In addition, we sought to determine whether there was a magnitude effect with delayed food in the allomorphic situation. Choice of immediate food and immediate cocaine increased with amount and dose, respectively. Choice functions for immediate food and cocaine generally shifted leftward as delay increased. Compared to isomorphic situations in which food was the immediate alternative, delayed food was discounted more steeply in allomorphic situations where cocaine was the immediate alternative. Notably, discounting was not affected by the magnitude of the delayed reinforcer. These data indicate that how steeply a delayed nondrug reinforcer is discounted may depend more on the qualitative characteristics of the immediate reinforcer and less on the magnitude of the delayed one. (c) 2015 APA, all rights reserved).

Modeling of dislocation dynamics in germanium Czochralski growth

NASA Astrophysics Data System (ADS)

Artemyev, V. V.; Smirnov, A. D.; Kalaev, V. V.; Mamedov, V. M.; Sidko, A. P.; Podkopaev, O. I.; Kravtsova, E. D.; Shimansky, A. F.

2017-06-01

Obtaining very high-purity germanium crystals with low dislocation density is a practically difficult problem, which requires knowledge and experience in growth processes. Dislocation density is one of the most important parameters defining the quality of germanium crystal. In this paper, we have performed experimental study of dislocation density during 4-in. germanium crystal growth using the Czochralski method and comprehensive unsteady modeling of the same crystal growth processes, taking into account global heat transfer, melt flow and melt/crystal interface shape evolution. Thermal stresses in the crystal and their relaxation with generation of dislocations within the Alexander-Haasen model have been calculated simultaneously with crystallization dynamics. Comparison to experimental data showed reasonable agreement for the temperature, interface shape and dislocation density in the crystal between calculation and experiment.

Crucible-free pulling of germanium crystals

NASA Astrophysics Data System (ADS)

Wünscher, Michael; Lüdge, Anke; Riemann, Helge

2011-03-01

Commonly, germanium crystals are grown after the Czochralski (CZ) method. The crucible-free pedestal and floating zone (FZ) methods, which are widely used for silicon growth, are hardly known to be investigated for germanium. The germanium melt is more than twice as dense as liquid silicon, which could destabilize a floating zone. Additionally, the lower melting point and the related lower radiative heat loss is shown to reduce the stability especially of the FZ process with the consequence of a screw-like crystal growth. We found that the lower heat radiation of Ge can be compensated by the increased convective cooling of a helium atmosphere instead of the argon ambient. Under these conditions, the screw-like growth could be avoided. Unfortunately, the helium cooling deteriorates the melting behavior of the feed rod. Spikes appear along the open melt front, which touch on the induction coil. In order to improve the melting behavior, we used a lamp as a second energy source as well as a mixture of Ar and He. With this, we found a final solution for growing stable crystals from germanium by using both gases in different parts of the furnace. The experimental work is accompanied by the simulation of the stationary temperature field. The commercially available software FEMAG-FZ is used for axisymmetric calculations. Another tool for process development is the lateral photo-voltage scanning (LPS), which can determine the shape of the solid-liquid phase boundary by analyzing the growth striations in a lateral cut of a grown crystal. In addition to improvements of the process, these measurements can be compared with the calculated results and, hence, conduce to validate the calculation.

An Improved Heuristic Method for Subgraph Isomorphism Problem

NASA Astrophysics Data System (ADS)

Xiang, Yingzhuo; Han, Jiesi; Xu, Haijiang; Guo, Xin

2017-09-01

This paper focus on the subgraph isomorphism (SI) problem. We present an improved genetic algorithm, a heuristic method to search the optimal solution. The contribution of this paper is that we design a dedicated crossover algorithm and a new fitness function to measure the evolution process. Experiments show our improved genetic algorithm performs better than other heuristic methods. For a large graph, such as a subgraph of 40 nodes, our algorithm outperforms the traditional tree search algorithms. We find that the performance of our improved genetic algorithm does not decrease as the number of nodes in prototype graphs.

Experimental quantum annealing: case study involving the graph isomorphism problem.

PubMed

Zick, Kenneth M; Shehab, Omar; French, Matthew

2015-06-08

Quantum annealing is a proposed combinatorial optimization technique meant to exploit quantum mechanical effects such as tunneling and entanglement. Real-world quantum annealing-based solvers require a combination of annealing and classical pre- and post-processing; at this early stage, little is known about how to partition and optimize the processing. This article presents an experimental case study of quantum annealing and some of the factors involved in real-world solvers, using a 504-qubit D-Wave Two machine and the graph isomorphism problem. To illustrate the role of classical pre-processing, a compact Hamiltonian is presented that enables a reduced Ising model for each problem instance. On random N-vertex graphs, the median number of variables is reduced from N(2) to fewer than N log2 N and solvable graph sizes increase from N = 5 to N = 13. Additionally, error correction via classical post-processing majority voting is evaluated. While the solution times are not competitive with classical approaches to graph isomorphism, the enhanced solver ultimately classified correctly every problem that was mapped to the processor and demonstrated clear advantages over the baseline approach. The results shed some light on the nature of real-world quantum annealing and the associated hybrid classical-quantum solvers.

Experimental quantum annealing: case study involving the graph isomorphism problem

PubMed Central

Zick, Kenneth M.; Shehab, Omar; French, Matthew

2015-01-01

Quantum annealing is a proposed combinatorial optimization technique meant to exploit quantum mechanical effects such as tunneling and entanglement. Real-world quantum annealing-based solvers require a combination of annealing and classical pre- and post-processing; at this early stage, little is known about how to partition and optimize the processing. This article presents an experimental case study of quantum annealing and some of the factors involved in real-world solvers, using a 504-qubit D-Wave Two machine and the graph isomorphism problem. To illustrate the role of classical pre-processing, a compact Hamiltonian is presented that enables a reduced Ising model for each problem instance. On random N-vertex graphs, the median number of variables is reduced from N2 to fewer than N log2 N and solvable graph sizes increase from N = 5 to N = 13. Additionally, error correction via classical post-processing majority voting is evaluated. While the solution times are not competitive with classical approaches to graph isomorphism, the enhanced solver ultimately classified correctly every problem that was mapped to the processor and demonstrated clear advantages over the baseline approach. The results shed some light on the nature of real-world quantum annealing and the associated hybrid classical-quantum solvers. PMID:26053973

Low-temperature irradiation-induced defects in germanium: In situ analysis

NASA Astrophysics Data System (ADS)

Mesli, A.; Dobaczewski, L.; Nielsen, K. Bonde; Kolkovsky, Vl.; Petersen, M. Christian; Larsen, A. Nylandsted

2008-10-01

The electronic properties of defects resulting from electron irradiation of germanium at low temperatures have been investigated. The recent success in preparing n+p junctions on germanium has opened a new opportunity to address fundamental questions regarding point defects and their related energy levels by allowing an access to the lower half of the band gap. In this work we apply various space-charge capacitance-transient spectroscopy techniques connected on line with the electron-beam facility. In n -type germanium we identify a level at about 0.14 eV below the conduction band whose properties resemble in many respects those of a defect assigned previously to the close vacancy-interstitial or Frenkel pair. This pair seems to annihilate over a small barrier at about 70 K, and its stability is particularly sensitive to the irradiation temperature and energy. We also observe two coupled levels at 0.08 and 0.24 eV below the conduction band stable up to 160 K. Recent independent theoretical work has predicted the existence of the single and double donor of the germanium interstitial with energy levels matching exactly these two values. Given these identifications hold, they mark a major difference with silicon where both the Frenkel pair and self-interstitial have never been caught. In p -type germanium, two levels were found. The shallower one, located at about 0.14 eV above the valence band, is tentatively assigned to the vacancy. It exhibits a field-driven instability at about 80 K making its analysis quite difficult. The application of a reverse bias, required by the space-charge spectroscopy, leads to a strong drift process sweeping this defect out of the observation area without necessarily provoking its annealing. Unlike silicon, in which the vacancy has four charge states, only one vacancy-related level seems to exist in germanium and this level is very likely a double acceptor. Finally, a very peculiar observation is made on a hole midgap trap, which, in

Scattering theory for graphs isomorphic to a regular tree at infinity

NASA Astrophysics Data System (ADS)

Colin de Verdière, Yves; Truc, Françoise

2013-06-01

We describe the spectral theory of the adjacency operator of a graph which is isomorphic to a regular tree at infinity. Using some combinatorics, we reduce the problem to a scattering problem for a finite rank perturbation of the adjacency operator on a regular tree. We develop this scattering theory using the classical recipes for Schrödinger operators in Euclidian spaces.

Effect of Inoculant Alloy Selection and Particle Size on Efficiency of Isomorphic Inoculation of Ti-Al

PubMed Central

Rouat, Bernard; Daloz, Dominique; Bouzy, Emmanuel

2018-01-01

The process of isomorphic inoculation relies on precise selection of inoculant alloys for a given system. Three alloys, Ti-10Al-25Nb, Ti-25Al-10Ta, and Ti-47Ta (at %) were selected as potential isomorphic inoculants for a Ti-46Al alloy. The binary Ti-Ta alloy selected was found to be ineffective as an inoculant due to its large density difference with the melt, causing the particles to settle. Both ternary alloys were successfully implemented as isomorphic inoculants that decreased the equiaxed grain size and increased the equiaxed fraction in their ingots. The degree of grain refinement obtained was found to be dependent on the number of particles introduced to the melt. Also, more new grains were formed than particles added to the melt. The grains/particle efficiency varied from greater than one to nearly twenty as the size of the particle increased. This is attributed to the breaking up of particles into smaller particles by dissolution in the melt. For a given particle size, Ti-Al-Ta and Ti-Al-Nb particles were found to have a roughly similar grain/particle efficiency. PMID:29693591

A square-plate piezoelectric linear motor operating in two orthogonal and isomorphic face-diagonal-bending modes.

PubMed

Ci, Penghong; Chen, Zhijiang; Liu, Guoxi; Dong, Shuxiang

2014-01-01

We report a piezoelectric linear motor made of a single Pb(Zr,Ti)O3 square-plate, which operates in two orthogonal and isomorphic face-diagonal-bending modes to produce precision linear motion. A 15 × 15 × 2 mm prototype was fabricated, and the motor generated a driving force of up to 1.8 N and a speed of 170 mm/s under an applied voltage of 100 Vpp at the resonance frequency of 136.5 kHz. The motor shows such advantages as large driving force under relatively low driving voltage, simple structure, and stable motion because of its isomorphic face-diagonal-bending mode.

Bandgap-customizable germanium using lithographically determined biaxial tensile strain for silicon-compatible optoelectronics.

PubMed

Sukhdeo, David S; Nam, Donguk; Kang, Ju-Hyung; Brongersma, Mark L; Saraswat, Krishna C

2015-06-29

Strain engineering has proven to be vital for germanium-based photonics, in particular light emission. However, applying a large permanent biaxial tensile strain to germanium has been a challenge. We present a simple, CMOS-compatible technique to conveniently induce a large, spatially homogenous strain in circular structures patterned within germanium nanomembranes. Our technique works by concentrating and amplifying a pre-existing small strain into a circular region. Biaxial tensile strains as large as 1.11% are observed by Raman spectroscopy and are further confirmed by photoluminescence measurements, which show enhanced and redshifted light emission from the strained germanium. Our technique allows the amount of biaxial strain to be customized lithographically, allowing the bandgaps of different germanium structures to be independently customized in a single mask process.

Advances in fractal germanium micro/nanoclusters induced by gold: microstructures and properties.

PubMed

Chen, Zhiwen; Shek, Chan-Hung; Wu, C M Lawrence; Lai, Joseph K L

2014-02-01

Germanium materials are a class of unique semiconductor materials with widespread technological applications because of their valuable semiconducting, electrical, optical, and thermoelectric power properties in the fields of macro/mesoscopic materials and micro/nanodevices. In this review, we describe the efforts toward understanding the microstructures and various properties of the fractal germanium micro/nanoclusters induced by gold prepared by high vacuum thermal evaporation techniques, highlighting contributions from our laboratory. First, we present the integer and non-integer dimensional germanium micro/nanoclusters such as nanoparticles, nanorings, and nanofractals induced by gold and annealing. In particular, the nonlinear electrical behavior of a gold/germanium bilayer film with the interesting nanofractal is discussed in detail. In addition, the third-order optical nonlinearities of the fractal germanium nanocrystals embedded in gold matrix will be summarized by using the sensitive and reliable Z-scan techniques aimed to determine the nonlinear absorption coefficient and nonlinear refractive index. Finally, we emphasize the thermoelectric power properties of the gold/germanium bilayer films. The thermoelectric power measurement is considered to be a more effective method than the conductivity for investigating superlocalization in a percolating system. This research may provide a novel insight to modulate their competent performance and promote rational design of micro/nanodevices. Once mastered, germanium thin films with a variety of fascinating micro/nanoclusters will offer vast and unforeseen opportunities in the semiconductor industry as well as in other fields of science and technology.

Hydrothermal germanium over the southern East pacific rise.

PubMed

Mortlock, R A; Froelich, P N

1986-01-03

Germanium enrichment in the oceanic water column above the southern axis of the East Pacific Rise results from hydrothermal solutions emanating from hot springs along the rise crest. This plume signature provides a new oceanic tracer of reactions between seawater and sea floor basalts during hydrothermal alteration. In contrast to the sharp plumes of (3)He and manganese, the germanium plume is broad and diffuse, suggesting the existence of pervasive venting of low-temperature solutions off the ridge axis.

Adhesion and friction behavior of group 4 elements germanium, silicon, tin, and lead

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1975-01-01

Adhesion and friction studies were conducted with thin films of the group IV elements silicon, germanium, tin, and lead ion plated on the nickel (011) substrate. The mating surface was gold (111). Contacts were made for the elements in the clean state and with oxygen present. Adhesion and friction experiments were conducted at very light loads of 1 to 10 g. Sliding was at a speed of 0.7 mm/min. Friction results indicate that the more covalently bonded elements silicon and germanium exhibit lower adhesion and friction than the more metallic bonded tin and lead. The adhesion of gold to germanium was observed, and recrystallization of the transferred gold occurred. Plastic flow of germanium was seen with sliding. Oxygen reduced, but did not eliminate, the adhesion observed with germanium and silicon.

Parallel Process and Isomorphism: A Model for Decision Making in the Supervisory Triad

ERIC Educational Resources Information Center

Koltz, Rebecca L.; Odegard, Melissa A.; Feit, Stephen S.; Provost, Kent; Smith, Travis

2012-01-01

Parallel process and isomorphism are two supervisory concepts that are often discussed independently but rarely discussed in connection with each other. These two concepts, philosophically, have different historical roots, as well as different implications for interventions with regard to the supervisory triad. The authors examine the difference…

Influence of Containment on the Growth of Germanium-Silicon in Microgravity

NASA Technical Reports Server (NTRS)

Volz, M. P.; Mazuruk, K.; Croll, A.; Sorgenfrei, T.

2017-01-01

This investigation involves the comparison of results achieved from three types of crystal growth of germanium and germanium-silicon alloys: Float zone growth, Bridgman growth, and Detached Bridgman growth. The fundamental goal of the proposed research is to determine the influence of containment on the processing-induced defects and impurity incorporation in germanium-silicon (GeSi) crystals (silicon concentration in the solid up to 5%) for three different growth configurations in order to quantitatively assess the improvements of crystal quality possible by detached growth.

Variable-Temperature Cryostat For Radiation-Damage Testing Of Germanium Detectors

NASA Technical Reports Server (NTRS)

Floyd, Samuel R.; Puc, Bernard P.

1992-01-01

Variable-temperature cryostats developed to study radiation damage to, and annealing of, germanium gamma-ray detectors. Two styles: one accommodates large single detector and one accommodates two medium-sized detectors. New cryostats allow complete testing of large-volume germanium gamma-ray detectors without breaking cryostat vacuum and removing detectors for annealing.

Causality in Statistical Power: Isomorphic Properties of Measurement, Research Design, Effect Size, and Sample Size.

PubMed

Heidel, R Eric

2016-01-01

Statistical power is the ability to detect a significant effect, given that the effect actually exists in a population. Like most statistical concepts, statistical power tends to induce cognitive dissonance in hepatology researchers. However, planning for statistical power by an a priori sample size calculation is of paramount importance when designing a research study. There are five specific empirical components that make up an a priori sample size calculation: the scale of measurement of the outcome, the research design, the magnitude of the effect size, the variance of the effect size, and the sample size. A framework grounded in the phenomenon of isomorphism, or interdependencies amongst different constructs with similar forms, will be presented to understand the isomorphic effects of decisions made on each of the five aforementioned components of statistical power.

Multidimensional Germanium-Based Materials as Anodes for Lithium-Ion Batteries.

PubMed

Qin, Jinwen; Cao, Minhua

2016-04-20

Metallic germanium is an ideal anode for lithium-ion batteries (LIBs), owing to its high theoretical capacity (1624 mA h g(-1) ) and low operating voltage. Herein, we highlight recent advances in the development of Ge-based anodes in LIBs, although improvements in their coulombic efficiency (CE), capacity retention, and rate performance are still required. One of the major concerns facing the development of Ge anodes is the controlled formation of microstructures. In this Focus Review, we summarize Ge-based materials with different structural dimensions, that is, zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), three-dimensional (3D), and even monolithic and macroscale structures. Moreover, the design of Ge-based oxide materials, as an effective route for achieving higher Li-storage capacities and cycling performance, is also discussed. Finally, we briefly summarize new types of Ge-based materials, such as ternary germanium oxides, germanium sulfides, and germanium phosphides, and predict that they will bring about a reformation in the field of LIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Time integrated optical emission studies of the laser produced germanium plasma

NASA Astrophysics Data System (ADS)

Iqbal, Javed; Ahmed, R.; Baig, M. A.

2017-04-01

We present new time integrated data on the optical emission spectra of laser produced germanium plasma using a Q-switched Nd:YAG laser (1064 nm), power density up to about 5  ×  109 W cm-2 in conjunction with a set of five spectrometers covering a spectral range from 200 nm to 720 nm. Well resolved structure due to the 4p5s  →  4p2 transition array of neutral germanium and a few multiplets of singly ionized germanium have been observed. Plasma temperature has been determined in the range (9000-11 000) K using four different techniques; two line ratio method, Boltzmann plot, Saha-Boltzmann plot and Marotta’s technique whereas electron density has been deduced from the Stark broadened line profiles in the range (0.5-5.0)  ×  1017 cm-3, depending on the laser pulse energy to produce the germanium plasma. Full width at half maximum (FWHM) of a number of neutral and singly ionized germanium lines have been extracted by the Lorentzian fit to the experimentally observed line profiles. In addition, we have compared the experimentally measured relative line strengths for the 4p5s 3P0,1,2  →  4p2 3P0,1,2 multiplet with that calculated in the LS-coupling scheme revealing that the intermediate coupling scheme is more appropriate for the level designations in germanium.

Reinventing the Concepts of Group and Isomorphism: The Case of Jessica and Sandra

ERIC Educational Resources Information Center

Larsen, Sean

2009-01-01

The purpose of this paper is to describe the process by which a pair of undergraduate students, participating in a teaching experiment, reinvented (with guidance) the concepts of group and isomorphism beginning with an exploration of the symmetries of an equilateral triangle. The intent of this description is to highlight some important insights…

A Case of Mimetic Isomorphism: A Short-Cut to Increasing Loyalty to Academia

ERIC Educational Resources Information Center

Orkodashvili, Mariam

2008-01-01

The paper discusses the process of shortening career path to leadership positions in academia that could serve as an example of mimetic isomorphism, where university tries to apply business-like quick result-oriented strategies. This strategy incentivizes young faculty to stay in universities and keep loyalty to academia. This process could also…

Bridgman Growth of Germanium

NASA Technical Reports Server (NTRS)

Szofran, F. R.; Volz, M. P.; Cobb, S. D.; Motakef, S.

1997-01-01

The high-magnetic-field crystal growth facility at the Marshall Space Flight Center will be briefly described. This facility has been used to grow bulk germanium by the Bridgman technique in magnetic fields up to 5 Tesla. The results of investigations of ampoule material on the interface shape and thermal field applied to the melt on stability against convection will be discussed.

High-resolution imaging gamma-ray spectroscopy with externally segmented germanium detectors

NASA Technical Reports Server (NTRS)

Callas, J. L.; Mahoney, W. A.; Varnell, L. S.; Wheaton, W. A.

1993-01-01

Externally segmented germanium detectors promise a breakthrough in gamma-ray imaging capabilities while retaining the superb energy resolution of germanium spectrometers. An angular resolution of 0.2 deg becomes practical by combining position-sensitive germanium detectors having a segment thickness of a few millimeters with a one-dimensional coded aperture located about a meter from the detectors. Correspondingly higher angular resolutions are possible with larger separations between the detectors and the coded aperture. Two-dimensional images can be obtained by rotating the instrument. Although the basic concept is similar to optical or X-ray coded-aperture imaging techniques, several complicating effects arise because of the penetrating nature of gamma rays. The complications include partial transmission through the coded aperture elements, Compton scattering in the germanium detectors, and high background count rates. Extensive electron-photon Monte Carlo modeling of a realistic detector/coded-aperture/collimator system has been performed. Results show that these complicating effects can be characterized and accounted for with no significant loss in instrument sensitivity.

Silicon and germanium nanowire electronics: physics of conventional and unconventional transistors

NASA Astrophysics Data System (ADS)

Weber, Walter M.; Mikolajick, Thomas

2017-06-01

Research in the field of electronics of 1D group-IV semiconductor structures has attracted increasing attention over the past 15 years. The exceptional combination of the unique 1D electronic transport properties with the mature material know-how of highly integrated silicon and germanium technology holds the promise of enhancing state-of-the-art electronics. In addition of providing conduction channels that can bring conventional field effect transistors to the uttermost scaling limits, the physics of 1D group IV nanowires endows new device principles. Such unconventional silicon and germanium nanowire devices are contenders for beyond complementary metal oxide semiconductor (CMOS) computing by virtue of their distinct switching behavior and higher expressive value. This review conveys to the reader a systematic recapitulation and analysis of the physics of silicon and germanium nanowires and the most relevant CMOS and CMOS-like devices built from silicon and germanium nanowires, including inversion mode, junctionless, steep-slope, quantum well and reconfigurable transistors.

Oriented bottom-up growth of armchair graphene nanoribbons on germanium

DOEpatents

Arnold, Michael Scott; Jacobberger, Robert Michael

2016-03-15

Graphene nanoribbon arrays, methods of growing graphene nanoribbon arrays and electronic and photonic devices incorporating the graphene nanoribbon arrays are provided. The graphene nanoribbons in the arrays are formed using a scalable, bottom-up, chemical vapor deposition (CVD) technique in which the (001) facet of the germanium is used to orient the graphene nanoribbon crystals along the [110] directions of the germanium.

Germanium: giving microelectronics an efficiency boost

USGS Publications Warehouse

Mercer, Celestine N.

2015-07-30

Germanium is an essentially nontoxic element, with the exception of only a few compounds. However, if dissolved concentrations in drinking water are as high as one or more parts per million chronic diseases may occur.

40 CFR 421.180 - Applicability: Description of the primary and secondary germanium and gallium subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... primary and secondary germanium and gallium subcategory. 421.180 Section 421.180 Protection of Environment... POINT SOURCE CATEGORY Primary and Secondary Germanium and Gallium Subcategory § 421.180 Applicability: Description of the primary and secondary germanium and gallium subcategory. The provisions of this subpart are...

40 CFR 421.180 - Applicability: Description of the primary and secondary germanium and gallium subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... primary and secondary germanium and gallium subcategory. 421.180 Section 421.180 Protection of Environment... POINT SOURCE CATEGORY Primary and Secondary Germanium and Gallium Subcategory § 421.180 Applicability: Description of the primary and secondary germanium and gallium subcategory. The provisions of this subpart are...

40 CFR 421.180 - Applicability: Description of the primary and secondary germanium and gallium subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... primary and secondary germanium and gallium subcategory. 421.180 Section 421.180 Protection of Environment... POINT SOURCE CATEGORY Primary and Secondary Germanium and Gallium Subcategory § 421.180 Applicability: Description of the primary and secondary germanium and gallium subcategory. The provisions of this subpart are...

40 CFR 421.180 - Applicability: Description of the primary and secondary germanium and gallium subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... primary and secondary germanium and gallium subcategory. 421.180 Section 421.180 Protection of Environment... POINT SOURCE CATEGORY Primary and Secondary Germanium and Gallium Subcategory § 421.180 Applicability: Description of the primary and secondary germanium and gallium subcategory. The provisions of this subpart are...

40 CFR 421.180 - Applicability: Description of the primary and secondary germanium and gallium subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... primary and secondary germanium and gallium subcategory. 421.180 Section 421.180 Protection of Environment... POINT SOURCE CATEGORY Primary and Secondary Germanium and Gallium Subcategory § 421.180 Applicability: Description of the primary and secondary germanium and gallium subcategory. The provisions of this subpart are...

Development of a new type of germanium detector for dark matter searches

NASA Astrophysics Data System (ADS)

Wei, Wenzhao

Monte Carlo simulation is an important tool used to develop a better understanding of important physical processes. This thesis describes three Monte Carlo simulations used to understand germanium detector response to low energy nuclear recoils and radiogenic backgrounds for direct dark matter searches. The first simulation is the verification of Barker-Mei model, a theoretical model for calculating the ionization efficiency for germanium detector for the energy range of 1 - 100 keV. Utilizing the shape analysis, a bin-to-bin comparison between simulation and experimental data was performed for verifying the accuracy of the Barker-Mei model. A percentage difference within 4% was achieved between data and simulation, which showed the validity of the Barker-Mei model. The second simulation is the study of a new type of germanium detector for n/gamma discrimination at 77 K with plasma time difference in pulse shape. Due to the poor time resolution, conventional P-type Point Contact (PPC) and coaxial germanium detectors are not capable of discriminating nuclear recoils from electron recoils. In this thesis, a new idea of using great detector granularity and plasma time difference in pulse shape to discriminate nuclear recoils from electron recoils with planar germanium detectors in strings was discussed. The anticipated sensitivity of this new detector array is shown for detecting dark matter. The last simulation is a study of a new type of germanium-detector array serving as a PMT screening facility for ultra-low background dark matter experiments using noble liquid xenon as detector material such LUX/LZ and XENON100/XENON1T. A well-shaped germanium detector array and a PMT were simulated to study the detector response to the signal and background for a better understanding of the radiogenic gamma rays from PMTs. The detector efficiency and other detector performance were presented in this work.

Determination of the Wetting Angle of Germanium and Germanium-Silicon Melts on Different Substrate Materials

NASA Technical Reports Server (NTRS)

Kaiser, Natalie; Croell, Arne; Szofran, F. R.; Cobb. S. D.; Dold, P.; Benz, K. W.

1999-01-01

During Bridgman growth of semiconductors detachment of the crystal and the melt meniscus has occasionally been observed, mainly under microgravity (microg) conditions. An important factor for detached growth is the wetting angle of the melt with the crucible material. High contact angles are more likely to result in detachment of the growing crystal from the ampoule wall. In order to achieve detached growth of germanium (Ge) and germanium-silicon (GeSi) crystals under 1g and microg conditions, sessile drop measurements were performed to determine the most suitable ampoule material as well as temperature dependence of the surface tension for GeSi. Sapphire, fused quartz, glassy carbon, graphite, SiC, pyrolytic Boron Nitride (pBN), AIN, and diamond were used as substrates. Furthermore, different cleaning procedures and surface treatments (etching, sandblasting, etc.) of the same substrate material and their effect on the wetting behavior were studied during these experiments. pBN and AIN substrates exhibited the highest contact angles with values around 170 deg.

Multiphysical simulation analysis of the dislocation structure in germanium single crystals

NASA Astrophysics Data System (ADS)

Podkopaev, O. I.; Artemyev, V. V.; Smirnov, A. D.; Mamedov, V. M.; Sid'ko, A. P.; Kalaev, V. V.; Kravtsova, E. D.; Shimanskii, A. F.

2016-09-01

To grow high-quality germanium crystals is one of the most important problems of growth industry. The dislocation density is an important parameter of the quality of single crystals. The dislocation densities in germanium crystals 100 mm in diameter, which have various shapes of the side surface and are grown by the Czochralski technique, are experimentally measured. The crystal growth is numerically simulated using heat-transfer and hydrodynamics models and the Alexander-Haasen dislocation model in terms of the CGSim software package. A comparison of the experimental and calculated dislocation densities shows that the dislocation model can be applied to study lattice defects in germanium crystals and to improve their quality.

Germanium geochemistry and mineralogy

USGS Publications Warehouse

Bernstein, L.R.

1985-01-01

Germanium is enriched in the following geologic environments: 1. (1) iron meteorites and terrestrial iron-nickel; 2. (2) sulfide ore deposits, particularly those hosted by sedimentary rocks; 3. (3) iron oxide deposits; 4. (4) oxidized zones of Ge-bearing sulfide deposits; 5. (5) pegmatites, greisens, and skarns; and 6. (6) coal and lignitized wood. In silicate melts, Ge is highly siderophile in the presence of native iron-nickel; otherwise, it is highly lithophile. Among silicate minerals, Ge is concentrated in those having less polymerized silicate tetrahedra such as olivine and topaz. In deposits formed from hydrothermal solutions, Ge tends to be enriched mostly in either sulfides or in fluorine-bearing phases; it is thus concentrated both in some hydrothermal sulfide deposits and in pegmatites, greisens, and skarns. In sulfide deposits that formed from solutions having low to moderate sulfur activity, Ge is concentrated in sphalerite in amounts up to 3000 ppm. Sulfide deposits that formed from solutions having higher sulfur activity allowed Ge to either form its own sulfides, particularly with Cu, or to substitute for As, Sn, or other metals in sulfosalts. The Ge in hydrothermal fluids probably derives from enrichment during the fractional crystallization of igneous fluids, or is due to the incorporation of Ge from the country rocks, particularly from those containing organic material. Germanium bonds to lignin-derivative organic compounds that are found in peat and lignite, accounting for its common concentration in coals and related organic material. Germanium is precipitated from water together with iron hydroxide, accounting for its concentration in some sedimentary and supergene iron oxide deposits. It also is able to substitute for Fe in magnetite in a variety of geologic environments. In the oxidized zone of Ge-bearing sulfide deposits, Ge is concentrated in oxides, hydroxides, and hydroxy-sulfates, sometimes forming its own minerals. It is particularly

Quantum interference magnetoconductance of polycrystalline germanium films in the variable-range hopping regime

NASA Astrophysics Data System (ADS)

Li, Zhaoguo; Peng, Liping; Zhang, Jicheng; Li, Jia; Zeng, Yong; Zhan, Zhiqiang; Wu, Weidong

2018-06-01

Direct evidence of quantum interference magnetotransport in polycrystalline germanium films in the variable-range hopping (VRH) regime is reported. The temperature dependence of the conductivity of germanium films fulfilled the Mott VRH mechanism with the form of ? in the low-temperature regime (?). For the magnetotransport behaviour of our germanium films in the VRH regime, a crossover, from negative magnetoconductance at the low-field to positive magnetoconductance at the high-field, is observed while the zero-field conductivity is higher than the critical value (?). In the regime of ?, the magnetoconductance is positive and quadratic in the field for some germanium films. These features are in agreement with the VRH magnetotransport theory based on the quantum interference effect among random paths in the hopping process.

Interfacial Properties of Germanium Nitride Dielectric Layers on Germanium.

DTIC Science & Technology

1986-09-30

choice or a process for growing Ge N , layers on germa - nium. a number of workers have employed various de. mum. posited layers on germanium. While...N00014-84-K-0459 V6 Office of Naval Research (Mr. Max N . Yoder, Electronic Division) 4: 800 North Quincy Street Arlington, Virginia 22217 Interfacial...z4) 3 Co0 C14 CM- Lfl n X sj E 𔃺 01 N S) Li (m* m n1 Ln m CU OT X)-(, (L 0IX) D/13si E- 1 0n CtZ) 4-4C ~ IN I- I L L0tX Cd) JN N in - Growth of

Naturally occurring vapor-liquid-solid (VLS) Whisker growth of germanium sulfide

USGS Publications Warehouse

Finkelman, R.B.; Larson, R.R.; Dwornik, E.J.

1974-01-01

The first naturally occurring terrestrial example of vapor-liquid-solid (VLS) growth has been observed in condensates from gases released by burning coal in culm banks. Scanning electron microscopy, X-ray diffraction, and energy dispersive analysis indicate that the crystals consist of elongated rods (??? 100 ??m) of germanium sulfide capped by bulbs depleted in germanium. ?? 1974.

Detached Bridgman Growth of Germanium and Germanium-Silicon Alloy Crystals

NASA Technical Reports Server (NTRS)

Szofran, F. R.; Volz, M. P.; Schweizer, M.; Cobb, S. D.; Motakef, S.; Croell, A.; Dold, P.; Curreri, Peter A. (Technical Monitor)

2002-01-01

Earth based experiments on the science of detached crystal growth are being conducted on germanium and germanium-silicon alloys (2 at% Si average composition) in preparation for a series of experiments aboard the International Space Station (ISS). The purpose of the microgravity experiments includes differentiating among proposed mechanisms contributing to detachment, and confirming or refining our understanding of the detachment mechanism. Because large contact angle are critical to detachment, sessile drop measurements were used to determine the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. The contact angles were 173 deg (Ge) and 165 deg (GeSi) for pBN. For fused silica, the contact angle decreases from 150 deg to an equilibrium value of 117 deg (Ge) or from 129 deg to an equilibrium value of 100 deg (GeSi) over the duration of the experiment. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. Results in this presentation will show that we have established the effects on detachment of ampoule material, pressure difference above and below the melt, and silicon concentration; samples that are nearly completely detached can be grown repeatedly in pBN.

Replicator equations, maximal cliques, and graph isomorphism.

PubMed

Pelillo, M

1999-11-15

We present a new energy-minimization framework for the graph isomorphism problem that is based on an equivalent maximum clique formulation. The approach is centered around a fundamental result proved by Motzkin and Straus in the mid-1960s, and recently expanded in various ways, which allows us to formulate the maximum clique problem in terms of a standard quadratic program. The attractive feature of this formulation is that a clear one-to-one correspondence exists between the solutions of the quadratic program and those in the original, combinatorial problem. To solve the program we use the so-called replicator equations--a class of straightforward continuous- and discrete-time dynamical systems developed in various branches of theoretical biology. We show how, despite their inherent inability to escape from local solutions, they nevertheless provide experimental results that are competitive with those obtained using more elaborate mean-field annealing heuristics.

Filterability of the suspension from germanium precipitation with aqueous tannin extract solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikhailov, N.F.; Petropol'skii, V.M.; Semenenko, L.E.

1978-01-01

We have already described the use of a neutral aqueous solution of tannin extract to recover germanium from collecting-mains liquor in coking plants. Further pilot commercial trials have encountered problems with the poor filterability of the precipitate obtained when germanium is extracted with this reagent in alkaline media. There are published references to the colloidal nature of the precipitated tannin-germanium complex. It is also known that the alkalinity of the medium influences the degree of association in colloidal systems to a marked extent. Accordingly, special research was needed to establish the relationship between the pH of the precipitation medium andmore » the filterability of the germanium deposit. Samples of collecting-mains liquor were taken from one of the southern coking plants to determine the optimum filtration behavior. The collecting-mains liquor should first be purged of volatile ammonia and then adjusted to pH = 6.5 to 6.7 for precipitation.« less

Germanium precipitation from collecting-mains liquor with tannin extract in an alkaline medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Medvedev, K.P.; Mikhailov, N.F.; Petrapol'skaya, V.M.

1976-01-01

It is proposed to precipitate germanium in a slightly alkaline medium, with a neutral solution of tannin extract in aqueous alkali. The effects of various factors on germanium recovery from collecting-mains liquors have been studied.

Germanium, Arsenic, and Selenium Abundances in Metal-poor Stars

NASA Astrophysics Data System (ADS)

Roederer, Ian U.

2012-09-01

The elements germanium (Ge, Z = 32), arsenic (As, Z = 33), and selenium (Se, Z = 34) span the transition from charged-particle or explosive synthesis of the iron-group elements to neutron-capture synthesis of heavier elements. Among these three elements, only the chemical evolution of germanium has been studied previously. Here we use archive observations made with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and observations from several ground-based facilities to study the chemical enrichment histories of seven stars with metallicities -2.6 <= [Fe/H] <= -0.4. We perform a standard abundance analysis of germanium, arsenic, selenium, and several other elements produced by neutron-capture reactions. When combined with previous derivations of germanium abundances in metal-poor stars, our sample reveals an increase in the [Ge/Fe] ratios at higher metallicities. This could mark the onset of the weak s-process contribution to germanium. In contrast, the [As/Fe] and [Se/Fe] ratios remain roughly constant. These data do not directly indicate the origin of germanium, arsenic, and selenium at low metallicity, but they suggest that the weak and main components of the s-process are not likely sources. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This research made use of StarCAT, hosted by the Mikulski Archive at the Space Telescope Science Institute (MAST). These data are associated with Programs GO-7348, GO-7433, GO-8197, GO-9048, GO-9455, and GO-9804.Based on data obtained from the European Southern Observatory (ESO) Science Archive Facility. These data are associated with Programs 67.D-0439(A), 074.C-0364(A), 076.B-0055(A), and 080.D-0347(A).This research has made use of the Keck Observatory Archive (KOA), which is operated by

SiGe derivatization by spontaneous reduction of aryl diazonium salts

NASA Astrophysics Data System (ADS)

Girard, A.; Geneste, F.; Coulon, N.; Cardinaud, C.; Mohammed-Brahim, T.

2013-10-01

Germanium semiconductors have interesting properties for FET-based biosensor applications since they possess high surface roughness allowing the immobilization of a high amount of receptors on a small surface area. Since SiGe combined low cost of Si and intrinsic properties of Ge with high mobility carriers, we focused the study on this particularly interesting material. The comparison of the efficiency of a functionalization process involving the spontaneous reduction of diazonium salts is studied on Si(1 0 0), SiGe and Ge semiconductors. XPS analysis of the functionalized surfaces reveals the presence of a covalent grafted layer on all the substrates that was confirmed by AFM. Interestingly, the modified Ge derivatives have still higher surface roughness after derivatization. To support the estimated thickness by XPS, a step measurement of the organic layers is done by AFM or by profilometer technique after a O2 plasma etching of the functionalized layer. This original method is well-adapted to measure the thickness of thin organic films on rough substrates such as germanium. The analyses show a higher chemical grafting on SiGe substrates compared with Si and Ge semiconductors.

Effect of ion-plated films of germanium and silicon on friction, wear, and oxidation of 52100 bearing steel

NASA Technical Reports Server (NTRS)

Buckley, D. H.; Spalvins, T.

1977-01-01

Friction and wear experiments were conducted with ion plated films of germanium and silicon on the surface of 52100 bearing steel both dry and in the presence of mineral oil. Both silicon and germanium were found to reduce wear, with germanium being more effective than silicon. An optimum film thickness of germanium for minimum wear without surface crack formation was found to be approximately 400 nanometers (4000 A). The presence of silicon and germanium on the 52100 bearing steel surface improved resistance to oxidation.

The time and temperature dependence of the thermoelectric properties of silicon-germanium alloy

NASA Technical Reports Server (NTRS)

Raag, V.

1975-01-01

Experimental data on the electrical resistivity and Seebeck coefficient of n-type and p-type silicon-germanium alloys are analyzed in terms of a solid-state dopant precipitation model proposed by Lifshitz and Slyozov (1961). Experimental findings on the time and temperature dependence of the thermal conductivity of these two types of alloy indicate that the thermal conductivity of silicon-germanium alloys changes with time, contrary to previous hypothesis. A preliminary model is presented which stipulates that the observed thermal conductivity decrease in silicon-germanium alloys is due partly to dopant precipitation underlying the electrical property changes and partly to enhanced alloying of the material. It is significant that all three properties asymptotically approach equilibrium values with time. Total characterization of these properties will enable the time change to be fully compensated in the design of a thermoelectric device employing silicon-germanium alloys.

Germanium layers grown by zone thermal crystallization from a discrete liquid source

NASA Astrophysics Data System (ADS)

Yatsenko, A. N.; Chebotarev, S. N.; Lozovskii, V. N.; Mohamed, A. A. A.; Erimeev, G. A.; Goncharova, L. M.; Varnavskaya, A. A.

2017-11-01

It is proposed and investigated a method for growing thin uniform germanium layers onto large silicon substrates. The technique uses the hexagonally arranged local sources filled with liquid germanium. Germanium evaporates on very close substrate and in these conditions the residual gases vapor pressure highly reduces. It is shown that to achieve uniformity of the deposited layer better than 97% the critical thickness of the vacuum zone must be equal to l cr = 1.2 mm for a hexagonal arranged system of round local sources with the radius of r = 0.75 mm and the distance between the sources of h = 0.5 mm.

Phase diagram of germanium telluride encapsulated in carbon nanotubes from first-principles searches

NASA Astrophysics Data System (ADS)

Wynn, Jamie M.; Medeiros, Paulo V. C.; Vasylenko, Andrij; Sloan, Jeremy; Quigley, David; Morris, Andrew J.

2017-12-01

Germanium telluride has attracted great research interest, primarily because of its phase-change properties. We have developed a general scheme, based on the ab initio random structure searching (AIRSS) method, for predicting the structures of encapsulated nanowires, and using this we predict a number of thermodynamically stable structures of GeTe nanowires encapsulated inside carbon nanotubes of radii under 9 Å . We construct the phase diagram of encapsulated GeTe, which provides quantitative predictions about the energetic favorability of different filling structures as a function of the nanotube radius, such as the formation of a quasi-one-dimensional rock-salt-like phase inside nanotubes of radii between 5.4 and 7.9 Å . Simulated TEM images of our structures show excellent agreement between our results and experimental TEM imagery. We show that, for some nanotubes, the nanowires undergo temperature-induced phase transitions from one crystalline structure to another due to vibrational contributions to the free energy, which is a first step toward nano-phase-change memory devices.

Germanium and Tin Based Anode Materials for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Ji, Dongsheng

The discovery of safe anode materials with high energy density for lithium-ion batteries has always been a significant topic. Group IV elements have been under intensive study for their high capability of alloying with lithium. Batteries with graphite and tin based anode material have already been applied in cell phones and vehicles. In order to apply group IV elements, their dramatic volume change during lithiation and delithiation processes is the key point to work on. Reducing the particle size is the most common method to buffer the volume expansion. This strategy has been applied on both germanium and tin based materials. Germanium based anode material has been made by two different synthesis methods. The amorphous Ge-C-Ti composite material was made by ball milling method and performed much better than other germanium alloy including Ge-Mg, Ge-Fe and Ge-Fe.Germanium sphere nano particles with diameter of around 50 nm have been made by solution method. After ball milled with graphite, the resulted product performed stable capacity over 500 mAh˙g-1 for more than 20 cycles. Ball milled graphite in the composite plays an important role of buffering volume change and stabilizing germanium. Sn-Fe alloy is one of the feasible solutions to stabilize tin. Sn 2Fe-C composite has been made by ball milling method. After optimizations of the ratio of precursors, reaction time, milling balls and electrolyte additives, the electrochemistry performance was improved. The anode performed 420 mAh˙ -1 at 1.0 mA/cm2 and maintained its structure after cycling at 2.0 mA/cm2. At 0.3 mA/cm2 cycling rate, the anode performed 978 mAh/cm3 after 500 cycles, which still exceeds the theoretical capacity of graphite.

Germanium detector vacuum encapsulation

NASA Technical Reports Server (NTRS)

Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

1991-01-01

This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

Children's Construction of Mathematical Knowledge in Solving Novel Isomorphic Problems in Concrete and Written Form.

ERIC Educational Resources Information Center

English, Lyn D.

1996-01-01

Presents case study data of low- and high-achieving nine-year olds focusing on construction and analogical transfer of mathematical knowledge during novel problem solving, as reflected in strategies for dealing with isomorphic combinatorial problems presented in hands-on and written form. Results showed that achievement level does not predict…

Synthesis and photoluminescence of ultra-pure germanium nanoparticles

NASA Astrophysics Data System (ADS)

Chivas, R.; Yerci, S.; Li, R.; Dal Negro, L.; Morse, T. F.

2011-09-01

We have used aerosol deposition to synthesize defect and micro-strain free, ultra-pure germanium nanoparticles. Transmission electron microscopy images show a core-shell configuration with highly crystalline core material. Powder X-ray diffraction measurements verify the presence of highly pure, nano-scale germanium with average crystallite size of 30 nm and micro-strain of 0.058%. X-ray photoelectron spectroscopy demonstrates that GeO x ( x ⩽ 2) shells cover the surfaces of the nanoparticles. Under optical excitation, these nanoparticles exhibit two separate emission bands at room temperature: a visible emission at 500 nm with 0.5-1 ns decay times and an intense near-infrared emission at 1575 nm with up to ˜20 μs lifetime.

Organotrichlorogermane synthesis by the reaction of elemental germanium, tetrachlorogermane and organic chloride via dichlorogermylene intermediate.

PubMed

Okamoto, Masaki; Asano, Takuya; Suzuki, Eiichi

2004-08-07

Organotrichlorogermanes were synthesized by the reaction of elemental germanium, tetrachlorogermane and organic chlorides, methyl, propyl, isopropyl and allyl chlorides. Dichlorogermylene formed by the reaction of elemental germanium with tetrachlorogermane was the reaction intermediate, which was inserted into the carbon-chlorine bond of the organic chloride to give organotrichlorogermane. When isopropyl or allyl chloride was used as an organic chloride, organotrichlorogermane was formed also in the absence of tetrachlorogermane. These chlorides were converted to hydrogen chloride, which subsequently reacted with elemental germanium to give the dichlorogermylene intermediate. The reaction of elemental germanium, tetrachlorogermane and organic chlorides provides a simple and easy method for synthesizing organotrichlorogermanes, and all the raw materials are easily available.

Explaining the accreditation process from the institutional isomorphism perspective: a case study of Jordanian primary healthcare centers.

PubMed

Alyahya, Mohammad; Hijazi, Heba; Harvey, Heather

2018-01-01

While the main focus of accreditation initiatives has been on hospitals, the implementation of these programs is a relatively new notion among other types of healthcare facilities. Correspondingly, this study aims to understand how accreditation is perceived among primary public healthcare centers using an isomorphic institutional theory. Semi-structured, in-depth interviews were conducted with 56 healthcare professionals and administrative staff from seven non-profit healthcare centers in Jordan using an explanatory case-study approach. The informants' narratives revealed that all three components of institutional theory: coercive, mimetic, and normative pressure, were drivers for institutional change in seeking accreditation. There was an overlapping and blending between the three various types of pressure. While participants perceived that healthcare centers faced formal and informal pressures to achieve accreditation, health centers were reluctant about the time, amount of effort, and their ability to achieve the accreditation. Ambiguity and fear of failure forced them to model successful ones. Moreover, the findings revealed that normative values of health professionals enhanced institutional isomorphism and influenced the accreditation process. Identifying these isomorphic changes may help key stakeholders to develop plans, policies, and procedures that could improve the quality of healthcare and enhance accreditation as an organizational strategic plan. Moreover, the study provided explanations of why and how organizations move to adopt new interventions and grow over time. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Germanium Requirements for National Defense,

DTIC Science & Technology

1991-07-01

work in this area involves development of hard exterior coating materials that will protect Ge windows but not adversely affect their optical...advanced electronic materials, is used in semiconductor devices, fiber optic systems, and infrared sensors for ships, aircraft, missiles, tanks and anti -tank...infrared sensors for ships, aircraft, missiles, tanks and anti -tank units. Because of its importance in these applications, germanium was added to the

Influence of Containment on the Growth of Silicon-Germanium: A Materials Science Flight Project

NASA Technical Reports Server (NTRS)

Volz, M. P.; Mazuruk, K.; Croell, A.

2012-01-01

This investigation involves the comparison of results achieved from three types of crystal growth of germanium and germanium-silicon alloys: (1) Float zone growth (2) Bridgman growth (3) Detached Bridgman growth crystal The fundamental goal of the proposed research is to determine the influence of containment on the processing-induced defects and impurity incorporation in germanium-silicon (GeSi) crystals (silicon concentration in the solid up to 5 at%) for three different growth configurations in order to quantitatively assess the improvements of crystal quality possible by detached growth.

Dramatic Changes in Thermoelectric Power of Germanium under Pressure: Printing n–p Junctions by Applied Stress

PubMed Central

Korobeinikov, Igor V.; Morozova, Natalia V.; Shchennikov, Vladimir V.; Ovsyannikov, Sergey V.

2017-01-01

Controlled tuning the electrical, optical, magnetic, mechanical and other characteristics of the leading semiconducting materials is one of the primary technological challenges. Here, we demonstrate that the electronic transport properties of conventional single-crystalline wafers of germanium may be dramatically tuned by application of moderate pressures. We investigated the thermoelectric power (Seebeck coefficient) of p– and n–type germanium under high pressure to 20 GPa. We established that an applied pressure of several GPa drastically shifts the electrical conduction to p–type. The p–type conduction is conserved across the semiconductor-metal phase transition at near 10 GPa. Upon pressure releasing, germanium transformed to a metastable st12 phase (Ge-III) with n–type semiconducting conductivity. We proposed that the unusual electronic properties of germanium in the original cubic-diamond-structured phase could result from a splitting of the “heavy” and “light” holes bands, and a related charge transfer between them. We suggested new innovative applications of germanium, e.g., in technologies of printing of n–p and n–p–n junctions by applied stress. Thus, our work has uncovered a new face of germanium as a ‘smart’ material. PMID:28290495

Structure of human thymidylate synthase under low-salt conditions.

PubMed

Lovelace, Leslie L; Minor, Wladek; Lebioda, Lukasz

2005-05-01

Human thymidylate synthase, a target in cancer chemotherapy, was crystallized from PEG 3350 with 30 mM ammonium sulfate (AS) in the crystallization medium. The crystals are isomorphous with the high-salt crystals ( approximately 2.0 M AS) and the structure has been solved and refined (R = 22.6%, R(free) = 24.3%) at 1.8 A resolution. The high- and low-AS-concentration structures are quite similar, with loop 181-197 is in the inactive conformation. Also, residues 95-106 and 129-135 (eukaryotic inserts region) show high mobility as assessed by poor electron density and high values of crystallographic temperature factors (residues 1-25 and 108-129 are disordered in both structures). The high mobility of this region may reflect the situation at physiological ionic strength. Of the four sulfate ions observed bound at 2.0 M AS, only two are present at 30 mM AS. The inactive conformation appears to be stabilized by the side chain of Val3 or a leucine residue from the disordered regions. The low-salt conditions of these crystals should be much more suitable for the study of thymidylate synthase inhibitors, especially those that utilize sulfate-binding sites to stabilize the inactive conformation of loop 181-197.

Electron tunnelling into amorphous germanium and silicon.

NASA Technical Reports Server (NTRS)

Smith, C. W.; Clark, A. H.

1972-01-01

Measurements of tunnel conductance versus bias, capacitance versus bias, and internal photoemission were made in the systems aluminum-oxide-amorphous germanium and aluminium-oxide-amorphous silicon. A function was extracted which expresses the deviation of these systems from the aluminium-oxide-aluminium system.

Single-Crystal Germanium Core Optoelectronic Fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Xiaoyu; Page, Ryan L.; Chaudhuri, Subhasis

Synthesis and fabrication of high-quality, small-core single-crystal germanium fibers that are photosensitive at the near-infrared and have low optical losses ≈1 dB cm-1 at 2 μm are reported. These fibers have potential applications in fiber-based spectroscopic imaging, nonlinear optical devices, and photodetection at the telecommunication wavelengths.

Self-assembled asymmetric membrane containing micron-size germanium for high capacity lithium ion batteries

DOE PAGES

Byrd, Ian; Chen, Hao; Webber, Theron; ...

2015-10-23

We report the formation of novel asymmetric membrane electrode containing micron-size (~5 μm) germanium powders through a self-assembly phase inversion method for high capacity lithium ion battery anode. 850 mA h g -1 capacity (70%) can be retained at a current density of 600 mA g -1 after 100 cycles with excellent rate performance. Such a high retention rate has rarely been seen for pristine micron-size germanium anodes. Moreover, scanning electron microscope studies reveal that germanium powders are uniformly embedded in a networking porous structure consisting of both nanopores and macropores. It is believed that such a unique porous structuremore » can efficiently accommodate the ~260% volume change during germanium alloying and de-alloying process, resulting in an enhanced cycling performance. Finally, these porous membrane electrodes can be manufactured in large scale using a roll-to-roll processing method.« less

Isomorphic semantic mapping of variant call format (VCF2RDF).

PubMed

Penha, Emanuel Diego S; Iriabho, Egiebade; Dussaq, Alex; de Oliveira, Diana Magalhães; Almeida, Jonas S

2017-02-15

The move of computational genomics workflows to Cloud Computing platforms is associated with a new level of integration and interoperability that challenges existing data representation formats. The Variant Calling Format (VCF) is in a particularly sensitive position in that regard, with both clinical and consumer-facing analysis tools relying on this self-contained description of genomic variation in Next Generation Sequencing (NGS) results. In this report we identify an isomorphic map between VCF and the reference Resource Description Framework. RDF is advanced by the World Wide Web Consortium (W3C) to enable representations of linked data that are both distributed and discoverable. The resulting ability to decompose VCF reports of genomic variation without loss of context addresses the need to modularize and govern NGS pipelines for Precision Medicine. Specifically, it provides the flexibility (i.e. the indexing) needed to support the wide variety of clinical scenarios and patient-facing governance where only part of the VCF data is fitting. Software libraries with a claim to be both domain-facing and consumer-facing have to pass the test of portability across the variety of devices that those consumers in fact adopt. That is, ideally the implementation should itself take place within the space defined by web technologies. Consequently, the isomorphic mapping function was implemented in JavaScript, and was tested in a variety of environments and devices, client and server side alike. These range from web browsers in mobile phones to the most popular micro service platform, NodeJS. The code is publicly available at https://github.com/ibl/VCFr , with a live deployment at: http://ibl.github.io/VCFr/ . jonas.almeida@stonybrookmedicine.edu. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Are Phonological Representations of Printed and Spoken Language Isomorphic? Evidence from the Restrictions on Unattested Onsets

ERIC Educational Resources Information Center

Berent, Iris

2008-01-01

Are the phonological representations of printed and spoken words isomorphic? This question is addressed by investigating the restrictions on onsets. Cross-linguistic research suggests that onsets of rising sonority are preferred to sonority plateaus, which, in turn, are preferred to sonority falls (e.g., bnif, bdif, lbif). Of interest is whether…

Cosmogenic activation of germanium used for tonne-scale rare event search experiments

NASA Astrophysics Data System (ADS)

Wei, W.-Z.; Mei, D.-M.; Zhang, C.

2017-11-01

We report a comprehensive study of cosmogenic activation of germanium used for tonne-scale rare event search experiments. The germanium exposure to cosmic rays on the Earth's surface are simulated with and without a shielding container using Geant4 for a given cosmic muon, neutron, and proton energy spectrum. The production rates of various radioactive isotopes are obtained for different sources separately. We find that fast neutron induced interactions dominate the production rate of cosmogenic activation. Geant4-based simulation results are compared with the calculation of ACTIVIA and the available experimental data. A reasonable agreement between Geant4 simulations and several experimental data sets is presented. We predict that cosmogenic activation of germanium can set limits to the sensitivity of the next generation of tonne-scale experiments.

Crystal Orientation Effect on the Subsurface Deformation of Monocrystalline Germanium in Nanometric Cutting.

PubMed

Lai, Min; Zhang, Xiaodong; Fang, Fengzhou

2017-12-01

Molecular dynamics simulations of nanometric cutting on monocrystalline germanium are conducted to investigate the subsurface deformation during and after nanometric cutting. The continuous random network model of amorphous germanium is established by molecular dynamics simulation, and its characteristic parameters are extracted to compare with those of the machined deformed layer. The coordination number distribution and radial distribution function (RDF) show that the machined surface presents the similar amorphous state. The anisotropic subsurface deformation is studied by nanometric cutting on the (010), (101), and (111) crystal planes of germanium, respectively. The deformed structures are prone to extend along the 110 slip system, which leads to the difference in the shape and thickness of the deformed layer on various directions and crystal planes. On machined surface, the greater thickness of subsurface deformed layer induces the greater surface recovery height. In order to get the critical thickness limit of deformed layer on machined surface of germanium, the optimized cutting direction on each crystal plane is suggested according to the relevance of the nanometric cutting to the nanoindentation.

Growth Behavior and Electronic Structure of Noble Metal-Doped Germanium Clusters.

PubMed

Mahtout, Sofiane; Siouani, Chaouki; Rabilloud, Franck

2018-01-18

Structures, energetics, and electronic properties of noble metal-doped germanium (MGe n with M = Cu, Ag, Au; n = 1-19) clusters are systematically investigated by using the density functional theory (DFT) approach. The endohedral structures in which the metal atom is encapsulated inside of a germanium cage appear at n = 10 when the dopant is Cu and n = 12 for M = Ag and Au. While Cu doping enhances the stability of the corresponding germanium frame, the binding energies of AgGe n and AuGe n are always lower than those of pure germanium clusters. Our results highlight the great stability of the CuGe 10 cluster in a D 4d structure and, to a lesser extent, that of AgGe 15 and AuGe 15 , which exhibits a hollow cage-like geometry. The sphere-type geometries obtained for n = 10-15 present a peculiar electronic structure in which the valence electrons of the noble metal and Ge atoms are delocalized and exhibit a shell structure associated with the quasi-spherical geometry. It is found that the coinage metal is able to give both s- and d-type electrons to be reorganized together with the valence electrons of Ge atoms through a pooling of electrons. The cluster size dependence of the stability, the frontier orbital energy gap, the vertical ionization potentials, and electron affinities are given.

Application of vacuum reduction and chlorinated distillation to enrich and prepare pure germanium from coal fly ash.

PubMed

Zhang, Lingen; Xu, Zhenming

2017-01-05

Germanium, as strategic reserve metal, plays critical role in high-tech industry. However, a contradiction of increasing consumption and scarcity of germanium resource is becoming more and more prominent. This paper proposed an integrated process to recycle germanium from coal fly ash. This technological process mainly consisted of two procedures: vacuum reduction with the purposes of enriching germanium and chlorinated distillation with the purposes of purifying germanium. Several highlights are summarized as follows: (i) Separation principle and reaction mechanism were discussed to understand this integrated process. (ii) Optimum designs and product analysis were developed to guide industrial recycling. The appropriate parameters for vacuum reduction process on the basis of response surface methodology (RSM) were 920.53°C and 259.63Pa, with 16.64wt.% reductant, and for the chlorinated distillation process, adding 8mol/l HCl and L/S 7, 8wt.% MnO 2 . The global recovery rate of germanium was 83.48±0.36% for the integrated process. (iii) This process overcomes the shortages of traditional process and shows its efficiency and environmental performance. It is significant in accordance with the "Reduce, Reuse and Recycle Principle" for solid waste and further provides a new opportunity for germanium recovery from waste by environment-friendly way. Copyright © 2016. Published by Elsevier B.V.

Crystal structure of the heptamolybdate(VI) (paramolybdate) ion, [Mo7O24]6-, in the ammonium and potassium tetrahydrate salts

USGS Publications Warehouse

Evans, H.T.; Gatehouse, B.M.; Leverett, P.

1975-01-01

The crystal structures of the isomorphous salts MI6 [Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods. Unit cell dimensions of these monoclinic compounds, space group P21/C with Z = 4, are, ammonium salt: a = 8.3934 ?? 0.0008, b = 36.1703 ?? 0.0045, c = 10.4715 ?? 0.0011 A??, ?? = 115.958?? ?? 0.008??; and potassium salt: a = 8.15 ?? 0.02, b = 35.68 ?? 0.1, c = 10.30 ?? 0.02 A??, ?? = 115.2?? ?? 02??. By use of multiple Weissenberg patterns, 8197 intensity data (Mo-K?? radiation) for the ammonium compound and 2178 (Cu-K?? radiation) for the potassium compound were estimated visually and used to test and refine Lindqvist's proposed structure in the space group P21/c. Lindqvist's structure was confirmed and the full matrix least-squares isotropic refinement led to R 0.076 (ammonium) 0.120 (potassium), with direct unambiguous location of the cations and water molecules in the potassium compound.

Evidence That Calls-Based and Mobility Networks Are Isomorphic

PubMed Central

Coscia, Michele; Hausmann, Ricardo

2015-01-01

Social relations involve both face-to-face interaction as well as telecommunications. We can observe the geography of phone calls and of the mobility of cell phones in space. These two phenomena can be described as networks of connections between different points in space. We use a dataset that includes billions of phone calls made in Colombia during a six-month period. We draw the two networks and find that the call-based network resembles a higher order aggregation of the mobility network and that both are isomorphic except for a higher spatial decay coefficient of the mobility network relative to the call-based network: when we discount distance effects on the call connections with the same decay observed for mobility connections, the two networks are virtually indistinguishable. PMID:26713730

Study of the possibility of growing germanium single crystals under low temperature gradients

NASA Astrophysics Data System (ADS)

Moskovskih, V. A.; Kasimkin, P. V.; Shlegel, V. N.; Vasiliev, Y. V.; Gridchin, V. A.; Podkopaev, O. I.; Zhdankov, V. N.

2014-03-01

The possibility of growing germanium single crystals under low temperature gradients in order to produce a dislocation-free material has been studied. Germanium crystals with a dislocation density of about 100-200 cm-2 have been grown in a system with a weight control of crystal growth at maximum axial gradients of about 1.5 K/cm.

Hydrometallurgical recovery of germanium from coal gasification fly ash: pilot plant scale evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arroyo, F.; Fernandez-Pereira, C.; Olivares, J.

2009-04-15

In this article, a hydrometallurgical method for the selective recovery of germanium from fly ash (FA) has been tested at pilot plant scale. The pilot plant flowsheet comprised a first stage of water leaching of FA, and a subsequent selective recovery of the germanium from the leachate by solvent extraction method. The solvent extraction method was based on Ge complexation with catechol in an aqueous solution followed by the extraction of the Ge-catechol complex (Ge(C{sub 6}H{sub 4}O{sub 2}){sub 3}{sup 2-}) with an extracting organic reagent (trioctylamine) diluted in an organic solvent (kerosene), followed by the subsequent stripping of the organicmore » extract. The process has been tested on a FA generated in an integrated gasification with combined cycle (IGCC) process. The paper describes the designed 5 kg/h pilot plant and the tests performed on it. Under the operational conditions tested, approximately 50% of germanium could be recovered from FA after a water extraction at room temperature. Regarding the solvent extraction method, the best operational conditions for obtaining a concentrated germanium-bearing solution practically free of impurities were as follows: extraction time equal to 20 min; aqueous phase/organic phase volumetric ratio equal to 5; stripping with 1 M NaOH, stripping time equal to 30 min, and stripping phase/organic phase volumetric ratio equal to 5. 95% of germanium were recovered from water leachates using those conditions.« less

Functionalization of Mechanochemically Passivated Germanium Nanoparticles via "Click" Chemistry

NASA Astrophysics Data System (ADS)

Purkait, Tapas Kumar

Germanium nanoparticles (Ge NPs) may be fascinating for their electronic and optoelectronic properties, as the band gap of Ge NPs can be tuned from the infrared into the visible range of solar spectru. Further functionalization of those nanoparticles may potentially lead to numerous applications ranging from surface attachment, bioimaging, drug delivery and nanoparticles based devices. Blue luminescent germanium nanoparticles were synthesized from a novel top-down mechanochemical process using high energy ball milling (HEBM) of bulk germanium. Various reactive organic molecules (such as, alkynes, nitriles, azides) were used in this process to react with fresh surface and passivate the surface through Ge-C or Ge-N bond. Various purification process, such as gel permeation chromatography (GPC), Soxhlet dailysis etc. were introduced to purify nanoparticles from molecular impurities. A size separation technique was developed using GPC. The size separated Ge NPs were characterize by TEM, small angle X-ray scattering (SAXS), UV-vis absorption and photoluminescence (PL) emission spectroscopy to investigate their size selective properties. Germanium nanoparticles with alkyne termini group were prepared by HEBM of germanium with a mixture of n-alkynes and alpha, o-diynes. Additional functionalization of those nanoparticles was achieved by copper(I) catalyzed azide-alkyne "click" reaction. A variety of organic and organometallic azides including biologically important glucals have been reacted in this manner resulting in nanopartilces adorned with ferrocenyl, trimethylsilyl, and glucal groups. Additional functionalization of those nanoparticles was achieved by reactions with various azides via a Cu(I) catalyzed azide-alkyne "click" reaction. Various azides, including PEG derivatives and cylcodextrin moiety, were grafted to the initially formed surface. Globular nanoparticle arrays were formed through interparticle linking via "click" chemistry or "host-guest" chemistry

Electrodeposition at room temperature of amorphous silicon and germanium nanowires in ionic liquid

NASA Astrophysics Data System (ADS)

Martineau, F.; Namur, K.; Mallet, J.; Delavoie, F.; Endres, F.; Troyon, M.; Molinari, M.

2009-11-01

The electrodeposition at room temperature of silicon and germanium nanowires from the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P1,4) containing SiCl4 as Si source or GeCl4 as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germanium nanowires of different diameters. The nanowires are composed of pure amorphous silicon or germanium. The nanowires have homogeneous cylindrical shape with a roughness of a few nanometres on the wire surfaces. The nanowires' diameters and lengths well match with the initial membrane characteristics. Preliminary photoluminescence experiments exhibit strong emission in the near infrared for the amorphous silicon nanowires.

Germanium films by polymer-assisted deposition

DOEpatents

Jia, Quanxi; Burrell, Anthony K.; Bauer, Eve; Ronning, Filip; McCleskey, Thomas Mark; Zou, Guifu

2013-01-15

Highly ordered Ge films are prepared directly on single crystal Si substrates by applying an aqueous coating solution having Ge-bound polymer onto the substrate and then heating in a hydrogen-containing atmosphere. A coating solution was prepared by mixing water, a germanium compound, ethylenediaminetetraacetic acid, and polyethyleneimine to form a first aqueous solution and then subjecting the first aqueous solution to ultrafiltration.

Confined in-fiber solidification and structural control of silicon and silicon-germanium microparticles.

PubMed

Gumennik, Alexander; Levy, Etgar C; Grena, Benjamin; Hou, Chong; Rein, Michael; Abouraddy, Ayman F; Joannopoulos, John D; Fink, Yoel

2017-07-11

Crystallization of microdroplets of molten alloys could, in principle, present a number of possible morphological outcomes, depending on the symmetry of the propagating solidification front and its velocity, such as axial or spherically symmetric species segregation. However, because of thermal or constitutional supercooling, resulting droplets often only display dendritic morphologies. Here we report on the crystallization of alloyed droplets of controlled micrometer dimensions comprising silicon and germanium, leading to a number of surprising outcomes. We first produce an array of silicon-germanium particles embedded in silica, through capillary breakup of an alloy-core silica-cladding fiber. Heating and subsequent controlled cooling of individual particles with a two-wavelength laser setup allows us to realize two different morphologies, the first being a silicon-germanium compositionally segregated Janus particle oriented with respect to the illumination axis and the second being a sphere made of dendrites of germanium in silicon. Gigapascal-level compressive stresses are measured within pure silicon solidified in silica as a direct consequence of volume-constrained solidification of a material undergoing anomalous expansion. The ability to generate microspheres with controlled morphology and unusual stresses could pave the way toward advanced integrated in-fiber electronic or optoelectronic devices.

Confined in-fiber solidification and structural control of silicon and silicon−germanium microparticles

PubMed Central

Gumennik, Alexander; Levy, Etgar C.; Grena, Benjamin; Hou, Chong; Rein, Michael; Abouraddy, Ayman F.; Joannopoulos, John D.; Fink, Yoel

2017-01-01

Crystallization of microdroplets of molten alloys could, in principle, present a number of possible morphological outcomes, depending on the symmetry of the propagating solidification front and its velocity, such as axial or spherically symmetric species segregation. However, because of thermal or constitutional supercooling, resulting droplets often only display dendritic morphologies. Here we report on the crystallization of alloyed droplets of controlled micrometer dimensions comprising silicon and germanium, leading to a number of surprising outcomes. We first produce an array of silicon−germanium particles embedded in silica, through capillary breakup of an alloy-core silica-cladding fiber. Heating and subsequent controlled cooling of individual particles with a two-wavelength laser setup allows us to realize two different morphologies, the first being a silicon−germanium compositionally segregated Janus particle oriented with respect to the illumination axis and the second being a sphere made of dendrites of germanium in silicon. Gigapascal-level compressive stresses are measured within pure silicon solidified in silica as a direct consequence of volume-constrained solidification of a material undergoing anomalous expansion. The ability to generate microspheres with controlled morphology and unusual stresses could pave the way toward advanced integrated in-fiber electronic or optoelectronic devices. PMID:28642348

Germanium and InGaAs/InP SPADs for single-photon detection in the near-infrared

NASA Astrophysics Data System (ADS)

Tosi, Alberto; Dalla Mora, Alberto; Zappa, Franco; Cova, Sergio

2007-09-01

Single-Photon Avalanche Diodes (SPADs) for near-infrared (800-1700 nm) wavelengths can be manufactured both in InGaAs/InP and in germanium. Recently, new InGaAs/InP SPADs became commercially available with good overall performances, but with the intrinsic bottleneck of strong afterpulsing effect, originated in the InP multiplication layer. At present, germanium technology is not exploited for single-photon detectors, but previous devices demonstrate lower afterpulsing even at very low temperatures and promising dark count rate when employing pure manufacturing process. In this work, we compare germanium and InGaAs/InP SPADs in terms of dark counts, afterpulsing, timing jitter, and quantum efficiency. Eventually, we highlight the motivations for considering germanium as a key material for single-photon counting in the NIR.

Ultrafast All-Optical Switching of Germanium-Based Flexible Metaphotonic Devices.

PubMed

Lim, Wen Xiang; Manjappa, Manukumara; Srivastava, Yogesh Kumar; Cong, Longqing; Kumar, Abhishek; MacDonald, Kevin F; Singh, Ranjan

2018-03-01

Incorporating semiconductors as active media into metamaterials offers opportunities for a wide range of dynamically switchable/tunable, technologically relevant optical functionalities enabled by strong, resonant light-matter interactions within the semiconductor. Here, a germanium-thin-film-based flexible metaphotonic device for ultrafast optical switching of terahertz radiation is experimentally demonstrated. A resonant transmission modulation depth of 90% is achieved, with an ultrafast full recovery time of 17 ps. An observed sub-picosecond decay constant of 670 fs is attributed to the presence of trap-assisted recombination sites in the thermally evaporated germanium film. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reduced graphene oxide-germanium quantum dot nanocomposite: electronic, optical and magnetic properties

NASA Astrophysics Data System (ADS)

Amollo, Tabitha A.; Mola, Genene T.; Nyamori, Vincent O.

2017-12-01

Graphene provides numerous possibilities for structural modification and functionalization of its carbon backbone. Localized magnetic moments can, as well, be induced in graphene by the formation of structural defects which include vacancies, edges, and adatoms. In this work, graphene was functionalized using germanium atoms, we report the effect of the Ge ad atoms on the structural, electrical, optical and magnetic properties of graphene. Reduced graphene oxide (rGO)-germanium quantum dot nanocomposites of high crystalline quality were synthesized by the microwave-assisted solvothermal reaction. Highly crystalline spherical shaped germanium quantum dots, of diameter ranging between 1.6-9.0 nm, are anchored on the basal planes of rGO. The nanocomposites exhibit high electrical conductivity with a sheet resistance of up to 16 Ω sq-1. The electrical conductivity is observed to increase with the increase in Ge content in the nanocomposites. High defect-induced magnetization is attained in the composites via germanium adatoms. The evolution of the magnetic moments in the nanocomposites and the coercivity showed marked dependence on the Ge quantum dots size and concentration. Quantum confinement effects is evidenced in the UV-vis absorbance spectra and photoluminescence emission spectra of the nanocomposites which show marked size-dependence. The composites manifest strong absorption in the UV region, strong luminescence in the near UV region, and a moderate luminescence in the visible region.

Removal and deposition efficiencies of the long-lived 222Rn daughters during etching of germanium surfaces

NASA Astrophysics Data System (ADS)

Zuzel, G.; Wójcik, M.; Majorovits, B.; Lampert, M. O.; Wendling, P.

2012-06-01

Removal and deposition efficiencies of the long-lived 222Rn daughters during etching from and onto surfaces of standard and high purity germanium were investigated. The standard etching procedure of Canberra-France used during production of high purity n-type germanium diodes was applied to germanium discs, which have been exposed earlier to a strong radon source for deposition of its progenies. An uncontaminated sample was etched in a solution containing 210Pb, 210Bi and 210Po. All isotopes were measured before and after etching with appropriate detectors. In contrast to copper and stainless steel, they were removed from germanium very efficiently. However, the reverse process was also observed. Considerable amounts of radioactive lead, bismuth and polonium isotopes present initially in the artificially polluted etchant were transferred to the clean high purity surface during processing of the sample.

Temperature-dependent Refractive Index of Silicon and Germanium

NASA Technical Reports Server (NTRS)

Frey, Bradley J.; Leviton, Douglas B.; Madison, Timothy J.

2006-01-01

Silicon and germanium are perhaps the two most well-understood semiconductor materials in the context of solid state device technologies and more recently micromachining and nanotechnology. Meanwhile, these two materials are also important in the field of infrared lens design. Optical instruments designed for the wavelength range where these two materials are transmissive achieve best performance when cooled to cryogenic temperatures to enhance signal from the scene over instrument background radiation. In order to enable high quality lens designs using silicon and germanium at cryogenic temperatures, we have measured the absolute refractive index of multiple prisms of these two materials using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, as a function of both wavelength and temperature. For silicon, we report absolute refractive index and thermo-optic coefficient (dn/dT) at temperatures ranging from 20 to 300 K at wavelengths from 1.1 to 5.6 pin, while for germanium, we cover temperatures ranging from 20 to 300 K and wavelengths from 1.9 to 5.5 microns. We compare our measurements with others in the literature and provide temperature-dependent Sellmeier coefficients based on our data to allow accurate interpolation of index to other wavelengths and temperatures. Citing the wide variety of values for the refractive indices of these two materials found in the literature, we reiterate the importance of measuring the refractive index of a sample from the same batch of raw material from which final optical components are cut when absolute accuracy greater than k5 x 10" is desired.

Experience from operating germanium detectors in GERDA

NASA Astrophysics Data System (ADS)

Palioselitis, Dimitrios; GERDA Collaboration

2015-05-01

Phase I of the Germanium Detector Array (GERDA) experiment, searching for the neutrinoless double beta (0νββ) decay of 76Ge, was completed in September 2013. The most competitive half-life lower limit for the 0νββ decay of 76Ge was set (T-0ν1/2 > 2.1 · 1025 yr at 90% C.L.). GERDA operates bare Ge diodes immersed in liquid argon. During Phase I, mainly refurbished semi-coaxial high purity Ge detectors from previous experiments were used. The experience gained with handling and operating bare Ge diodes in liquid argon, as well as the stability and performance of the detectors during GERDA Phase I are presented. Thirty additional new enriched BEGe-type detectors were produced and will be used in Phase II. A subgroup of these detectors has already been used successfully in GERDA Phase I. The present paper gives an overview of the production chain of the new germanium detectors, the steps taken to minimise the exposure to cosmic radiation during manufacturing, and the first results of characterisation measurements in vacuum cryostats.

Multiple-step preparation and physicochemical characterization of crystalline α-germanium hydrogenphosphate

NASA Astrophysics Data System (ADS)

Romano, Ricardo; Ruiz, Ana I.; Alves, Oswaldo L.

2004-04-01

The reaction between germanium oxide and phosphoric acid has previously been described and led to impure germanium hydrogenphosphate samples with low crystallinity. A new multiple-step route involving the same reaction under refluxing and soft hydrothermal conditions is described for the preparation of pure and crystalline α-GeP. The physicochemical characterization of the samples allows accompaniment of the reaction evolution as well as determining short- and long-range structural organization. The phase purity of the α-GeP sample was confirmed by applying Rietveld's profile analysis, which also determined the cell parameters of its crystals.

Quantum field theory and the linguistic Minimalist Program: a remarkable isomorphism

NASA Astrophysics Data System (ADS)

Piattelli-Palmarini, M.; Vitiello, G.

2017-08-01

By resorting to recent results, we show that an isomorphism exist between linguistic features of the Minimalist Program and the quantum field theory formalism of condensed matter physics. Specific linguistic features which admit a representation in terms of the many-body algebraic formalism are the unconstrained nature of recursive Merge, the operation of the Labeling Algorithm, the difference between pronounced and un-pronounced copies of elements in a sentence and the build-up of the Fibonacci sequence in the syntactic derivation of sentence structures. The collective dynamical nature of the formation process of Logical Forms leading to the individuation of the manifold of concepts and the computational self-consistency of languages are also discussed.

High temperature material interactions of thermoelectric systems using silicon germanium.

NASA Technical Reports Server (NTRS)

Stapfer, G.; Truscello, V. C.

1973-01-01

The efficient use of silicon germanium thermoelectric material for radioisotope thermoelectric generators (RTG) is achieved by operation at relatively high temperatures. The insulation technique which is most appropriate for this application uses multiple layers of molybdenum foil and astroquartz. Even so, the long term operation of these materials at elevated temperatures can cause material interaction to occur within the system. To investigate these material interactions, the Jet Propulsion Laboratory is currently testing a number of thermoelectric modules which use four silicon germanium thermoelectric couples in conjunction with the multifoil thermal insulation. The paper discusses the results of the ongoing four-couple module test program and correlates test results with those of a basic material test program.

Germanium recovery from gasification fly ash: evaluation of end-products obtained by precipitation methods.

PubMed

Arroyo, Fátima; Font, Oriol; Fernández-Pereira, Constantino; Querol, Xavier; Juan, Roberto; Ruiz, Carmen; Coca, Pilar

2009-08-15

In this study the purity of the germanium end-products obtained by two different precipitation methods carried out on germanium-bearing solutions was evaluated as a last step of a hydrometallurgy process for the recovery of this valuable element from the Puertollano Integrated Gasification Combined Cycle (IGCC) fly ash. Since H(2)S is produced as a by-product in the gas cleaning system of the Puertollano IGCC plant, precipitation of germanium as GeS(2) was tested by sulfiding the Ge-bearing solutions. The technological and hazardous issues that surround H(2)S handling conducted to investigate a novel precipitation procedure: precipitation as an organic complex by adding 1,2-dihydroxy benzene pyrocatechol (CAT) and cetyltrimethylammonium bromide (CTAB) to the Ge-bearing solutions. Relatively high purity Ge end-products (90 and 93% hexagonal-GeO(2) purity, respectively) were obtained by precipitating Ge from enriched solutions, as GeS(2) sulfiding the solutions with H(2)S, or as organic complex with CAT/CTAB mixtures and subsequent roasting of the precipitates. Both methods showed high efficiency (>99%) to precipitate selectively Ge using a single precipitation stage from germanium-bearing solutions.

Enabling Energy Efficiency and Polarity Control in Germanium Nanowire Transistors by Individually Gated Nanojunctions.

PubMed

Trommer, Jens; Heinzig, André; Mühle, Uwe; Löffler, Markus; Winzer, Annett; Jordan, Paul M; Beister, Jürgen; Baldauf, Tim; Geidel, Marion; Adolphi, Barbara; Zschech, Ehrenfried; Mikolajick, Thomas; Weber, Walter M

2017-02-28

Germanium is a promising material for future very large scale integration transistors, due to its superior hole mobility. However, germanium-based devices typically suffer from high reverse junction leakage due to the low band-gap energy of 0.66 eV and therefore are characterized by high static power dissipation. In this paper, we experimentally demonstrate a solution to suppress the off-state leakage in germanium nanowire Schottky barrier transistors. Thereto, a device layout with two independent gates is used to induce an additional energy barrier to the channel that blocks the undesired carrier type. In addition, the polarity of the same doping-free device can be dynamically switched between p- and n-type. The shown germanium nanowire approach is able to outperform previous polarity-controllable device concepts on other material systems in terms of threshold voltages and normalized on-currents. The dielectric and Schottky barrier interface properties of the device are analyzed in detail. Finite-element drift-diffusion simulations reveal that both leakage current suppression and polarity control can also be achieved at highly scaled geometries, providing solutions for future energy-efficient systems.

Fabricating Germanium Interfaces for Battery Applications

NASA Astrophysics Data System (ADS)

Serino, Andrew Clark

The experimental results presented herein detail the importance of material surfaces in device performance. We have demonstrated this importance by furthering and applying our understanding of germanium surfaces to a number of real-world applications. Pure and stable dispersions of germanane, an "all-surface" form of germanium, were created through solid-state synthesis followed by ultrasonication and centrifugation. These dispersions were used to fabricate germanane-based, high-performance, Li-ion anodes with capacities of ˜1100 mA-h/g, capacity retention over 100 cycles, and Coulombic efficiency of 99%. Additionally, carborane monolayers were self-assembled on Ge(100) and Ge(111) surfaces through carboxylic acid tethers, and found to be capable of tuning the surface work function by ˜0.4 eV without significantly affecting surface wettability. These capabilities are important for increasing device efficiency while minimizing complications associated with processing. Lastly, we introduce the concept of the molecular battery, a possible design using a layer-by-layer deposition approach, and our steps toward its realization. In this pursuit, we explored the assembly of metal-organic coordination of carborane-based linkers, as well as the capabilities of a film of benzene-based linkers (<50 nm) as a Li-ion battery separator using a Ge anode as a tool for analyzing performance.

Electrical Manipulation of Donor Spin Qubits in Silicon and Germanium

NASA Astrophysics Data System (ADS)

Sigillito, Anthony James

Many proposals for quantum information devices rely on electronic or nuclear spins in semiconductors because of their long coherence times and compatibility with industrial fabrication processes. One of the most notable qubits is the electron spin bound to phosphorus donors in silicon, which offers coherence times exceeding seconds at low temperatures. These donors are naturally isolated from their environments to the extent that silicon has been coined a "semiconductor vacuum". While this makes for ultra-coherent qubits, it is difficult to couple two remote donors so quantum information proposals rely on high density arrays of qubits. Here, single qubit addressability becomes an issue. Ideally one would address individual qubits using electric fields which can be easily confined. Typically these schemes rely on tuning a donor spin qubit onto and off of resonance with a magnetic driving field. In this thesis, we measure the electrical tunability of phosphorus donors in silicon and use the extracted parameters to estimate the effects of electric-field noise on qubit coherence times. Our measurements show that donor ionization may set in before electron spins can be sufficiently tuned. We therefore explore two alternative options for qubit addressability. First, we demonstrate that nuclear spin qubits can be directly driven using electric fields instead of magnetic fields and show that this approach offers several advantages over magnetically driven spin resonance. In particular, spin transitions can occur at half the spin resonance frequency and double quantum transitions (magnetic-dipole forbidden) can occur. In a second approach to realizing tunable qubits in semiconductors, we explore the option of replacing silicon with germanium. We first measure the coherence and relaxation times for shallow donor spin qubits in natural and isotopically enriched germanium. We find that in isotopically enriched material, coherence times can exceed 1 ms and are limited by a

From Planck Constant to Isomorphicity Through Justice Paradox

NASA Astrophysics Data System (ADS)

Hidajatullah-Maksoed, Widastra

2015-05-01

Robert E. Scott in his ``Chaos theory and the Justice Paradox'', William & Mary Law Review, v 35, I 1, 329 (1993) wrotes''...As we approach the 21-st Century, the signs of social disarray are everywhere. Social critics observe the breakdown of core structure - the nuclear family, schools, neighborhoods & political groups''. For completions for ``soliton'' first coined by Morikazu TODA, comparing the ``Soliton on Scott-Russell aqueduct on the Union Canal near Heriot-WATT University, July 12, 1995 to Michael Stock works: ``a Fine WATT-Balance: Determination of Planck constant & Redefinition of Kilogram'', January 2011, we can concludes the inherencies between `chaos' & `soliton'. Further through ``string theory'' from Michio KAKU sought statements from Peter Mayr: Stringy world brane & Exponential hierarchy'', JHEP 11 (2000): ``if the 5-brane is embedded in flat 10-D space time, the 6-D Planck mass on the brane is infinite'' who also describes the relation of isomorphicity & ``string theory'', from whom denotes the smart city. Replace this text with your abstract body. Incredible acknowledgments to HE. Mr. Drs. P. SWANTORO & HE. Mr. Dr-HC Jakob OETAMA.

Silicon Germanium Cryogenic Low Noise Amplifiers

NASA Astrophysics Data System (ADS)

Bardin, J. C.; Montazeri, S.; Chang, Su-Wei

2017-05-01

Silicon germanium heterojunction bipolar transistors have emerged in the last decade as an excellent option for use in cryogenic low noise amplifiers. This paper begins with a review of the critical developments that have led to today’s cryogenic low noise amplifiers. Next, recent work focused on minimizing the power consumption of SiGe cryogenic amplifiers is presented. Finally, open issues related to the cryogenic noise properties of SiGe HBTs are discussed.

High-speed recovery of germanium in a convection-aided mode using functional porous hollow-fiber membranes.

PubMed

Ozawa, I; Saito, K; Sugita, K; Sato, K; Akiba, M; Sugo, T

2000-08-04

A porous hollow-fiber membrane capable of recovery of germanium from a liquid stream was prepared by radiation-induced graft polymerization of an epoxy-group-containing vinyl monomer, glycidyl methacrylate, and subsequent functionalization with 2,2'-iminodiethanol, di-2-propanolamine, N-methylglucamine, and 3-amino-1,2-propanediol. The functional group density was as high as 1.4 mol per kg of the resultant hollow fiber. The polymer chains containing functional groups surrounding the pores enabled a high-speed recovery of germanium during permeation of a germanium oxide (GeO2) solution through the pores of the hollow fiber. Because of a negligible diffusional mass-transfer resistance, germanium concentration changes with the effluent volume, i.e., breakthrough curves, overlapped irrespective of the residence time of the solution, which ranged from 0.37 to 3.7 s across the hollow fiber. After repeated use of adsorption and elution, the adsorption capacity did not deteriorate.

Enhanced light trapping by focused ion beam (FIB) induced self-organized nanoripples on germanium (100) surface

NASA Astrophysics Data System (ADS)

Kamaliya, Bhaveshkumar; Mote, Rakesh G.; Aslam, Mohammed; Fu, Jing

2018-03-01

In this paper, we demonstrate enhanced light trapping by self-organized nanoripples on the germanium surface. The enhanced light trapping leading to high absorption of light is confirmed by the experimental studies as well as the numerical simulations using the finite-difference time-domain method. We used gallium ion (Ga+) focused ion beam to enable the formation of the self-organized nanoripples on the germanium (100) surface. During the fabrication, the overlap of the scanning beam is varied from zero to negative value and found to influence the orientation of the nanoripples. Evolution of nanostructures with the variation of beam overlap is investigated. Parallel, perpendicular, and randomly aligned nanoripples with respect to the scanning direction are obtained via manipulation of the scanning beam overlap. 95% broadband absorptance is measured in the visible electromagnetic region for the nanorippled germanium surface. The reported light absorption enhancement can significantly improve the efficiency of germanium-silicon based photovoltaic systems.

Germanium multiphase equation of state

DOE PAGES

Crockett, Scott D.; Lorenzi-Venneri, Giulia De; Kress, Joel D.; ...

2014-05-07

A new SESAME multiphase germanium equation of state (EOS) has been developed using the best available experimental data and density functional theory (DFT) calculations. The equilibrium EOS includes the Ge I (diamond), the Ge II (β-Sn) and the liquid phases. The foundation of the EOS is based on density functional theory calculations which are used to determine the cold curve and the Debye temperature. Results are compared to Hugoniot data through the solid-solid and solid-liquid transitions. We propose some experiments to better understand the dynamics of this element

Force, Velocity, and Work: The Effects of Different Contexts on Students' Understanding of Vector Concepts Using Isomorphic Problems

ERIC Educational Resources Information Center

Barniol, Pablo; Zavala, Genaro

2014-01-01

In this article we compare students' understanding of vector concepts in problems with no physical context, and with three mechanics contexts: force, velocity, and work. Based on our "Test of Understanding of Vectors," a multiple-choice test presented elsewhere, we designed two isomorphic shorter versions of 12 items each: a test with no…

Super-elite plasma rings and the orbits of planets and satellites isomorphic to the orbits of electrons in the Bohr's model of the hydrogen atom

NASA Astrophysics Data System (ADS)

Rabinovich, B. I.

2007-10-01

This paper continues the series of papers [1 5] and generalizes the previous results to a proto-ring of magnetized plasma whose density decreases in the radial direction. The problem of quantization of the sector and orbital velocities, and of the radii and periods of revolution of elite plasma rings is considered. A new concept of super-elite rings is introduced. Their isomorphism with the orbits of the planets and planetary satellites in the Solar System is proved. This isomorphism also extends to the orbits of electrons in the Bohr’s model of the hydrogen atom.

Detached Bridgman Growth of Germanium and Germanium-Silicon Alloy Crystals

NASA Technical Reports Server (NTRS)

Szofran, F. R.; Volz, M. P.; Schweizer, M.; Kaiser, N.; Cobb, S. D.; Motakef, S.; Vujisic, L. J.; Croell, A.; Dold, P.; Rose, M. Franklin (Technical Monitor)

2001-01-01

Earth based experiments on the science of detached crystal growth are being conducted on germanium and germanium-silicon alloys (2at% Si average composition) in preparation for a series of experiments aboard the International Space Station (ISS) to differentiate among proposed mechanisms contributing to detachment. Sessile drop measurements were first carried out for a large number of substrates made of potential ampoule materials to determine the contact angles and the surface tension as a function of temperature and composition. The process atmosphere and duration of the experiment (for some cases) were also found to have significant influence on the wetting angle. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. The contact angles were 173 deg (Ge) and 165 deg (GeSi) for pBN. For fused silica, the contact angle decreases to an equilibrium value with duration of measurement ranging from 150 to 117 deg (Ge), 129 to 100 deg (GeSi). Forming gas (Ar + 2% H2) and vacuum have been used in the growth ampoules. With gas in the ampoule, a variation of the temperature profile during growth has been used to control the pressure difference between the top of the melt and the volume below the melt caused by detachment of the growing crystal. The stability of detachment has been modeled and substantial insight has been gained into the reasons that detachment has most often been observed in reduced gravity but nonetheless has occurred randomly even there. An empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed and will be presented. Methods for determining the nature and extent of detachment include profilometry and optical and electron microscopy. This surface study is the subject of another presentation at this Congress. Results in this presentation will show that we have

Purification of Germanium Crystals by Zone Refining

NASA Astrophysics Data System (ADS)

Kooi, Kyler; Yang, Gang; Mei, Dongming

2016-09-01

Germanium zone refining is one of the most important techniques used to produce high purity germanium (HPGe) single crystals for the fabrication of nuclear radiation detectors. During zone refining the impurities are isolated to different parts of the ingot. In practice, the effective isolation of an impurity is dependent on many parameters, including molten zone travel speed, the ratio of ingot length to molten zone width, and number of passes. By studying the theory of these influential factors, perfecting our cleaning and preparation procedures, and analyzing the origin and distribution of our impurities (aluminum, boron, gallium, and phosphorous) identified using photothermal ionization spectroscopy (PTIS), we have optimized these parameters to produce HPGe. We have achieved a net impurity level of 1010 /cm3 for our zone-refined ingots, measured with van der Pauw and Hall-effect methods. Zone-refined ingots of this purity can be processed into a detector grade HPGe single crystal, which can be used to fabricate detectors for dark matter and neutrinoless double beta decay detection. This project was financially supported by DOE Grant (DE-FG02-10ER46709) and the State Governor's Research Center.

Two-Dimensional Spatial Imaging of Charge Transport in Germanium Crystals at Cryogenic Temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moffatt, Robert

2016-03-01

In this dissertation, I describe a novel apparatus for studying the transport of charge in semiconductors at cryogenic temperatures. The motivation to conduct this experiment originated from an asymmetry observed between the behavior of electrons and holes in the germanium detector crystals used by the Cryogenic Dark Matter Search (CDMS). This asymmetry is a consequence of the anisotropic propagation of electrons in germanium at cryogenic temperatures. To better model our detectors, we incorporated this effect into our Monte Carlo simulations of charge transport. The purpose of the experiment described in this dissertation is to test those models in detail. Ourmore » measurements have allowed us to discover a shortcoming in our most recent Monte Carlo simulations of electrons in germanium. This discovery would not have been possible without the measurement of the full, two-dimensional charge distribution, which our experimental apparatus has allowed for the first time at cryogenic temperatures.« less

Geometrical and band-structure effects on phonon-limited hole mobility in rectangular cross-sectional germanium nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, H., E-mail: tanaka@semicon.kuee.kyoto-u.ac.jp; Mori, S.; Morioka, N.

2014-12-21

We calculated the phonon-limited hole mobility in rectangular cross-sectional [001], [110], [111], and [112]-oriented germanium nanowires, and the hole transport characteristics were investigated. A tight-binding approximation was used for holes, and phonons were described by a valence force field model. Then, scattering probability of holes by phonons was calculated taking account of hole-phonon interaction atomistically, and the linearized Boltzmann's transport equation was solved to calculate the hole mobility at low longitudinal field. The dependence of the hole mobility on nanowire geometry was analyzed in terms of the valence band structure of germanium nanowires, and it was found that the dependencemore » was qualitatively reproduced by considering an average effective mass and the density of states of holes. The calculation revealed that [110] germanium nanowires with large height along the [001] direction show high hole mobility. Germanium nanowires with this geometry are also expected to exhibit high electron mobility in our previous work, and thus they are promising for complementary metal-oxide-semiconductor (CMOS) applications.« less

Analysis of high-purity germanium dioxide by ETV-ICP-AES with preliminary concentration of trace elements.

PubMed

Medvedev, Nickolay S; Shaverina, Anastasiya V; Tsygankova, Alphiya R; Saprykin, Anatoly I

2016-08-01

The paper presents a combined technique of germanium dioxide analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) with preconcentration of trace elements by distilling off matrix and electrothermal (ETV) introduction of the trace elements concentrate into the ICP. Evaluation of metrological characteristics of the developed technique of high-purity germanium dioxide analysis was performed. The limits of detection (LODs) for 25 trace elements ranged from 0.05 to 20ng/g. The accuracy of proposed technique is confirmed by "added-found" («or spiking») experiment and comparing the results of ETV-ICP-AES and ICP-AES analysis of high purity germanium dioxide samples. Copyright © 2016 Elsevier B.V. All rights reserved.

SiGe-on-insulator fabricated via germanium condensation following high-fluence Ge+ ion implantation

NASA Astrophysics Data System (ADS)

Anthony, R.; Haddara, Y. M.; Crowe, I. F.; Knights, A. P.

2017-08-01

Germanium condensation is demonstrated using a two-step wet oxidation of germanium implanted Silicon-On-Insulator (SOI). Samples of 220 nm thick SOI are implanted with a nominal fluence of 5 × 1016 cm-2 Ge+ at an energy of 33 keV. Primary post-implantation wet oxidation is performed initially at 870 °C for 70 min, with the aim of capping the sample without causing significant dose loss via Ge evaporation through the sample surface. This is followed by a secondary higher temperature wet oxidation at either 900 °C, 1000 °C, or 1080 °C. The germanium retained dose and concentration profile, and the oxide thickness is examined after primary oxidation, and various secondary oxidation times, using Rutherford backscattering analysis. A mixed SiGe oxide is observed to form during the primary oxidation followed by a pure silicon oxide after higher temperature secondary oxidation. The peak germanium concentration, which varies with secondary oxidation condition, is found to range from 43 at. % to 95 at. %, while the FWHM of the Ge profile varies from 13 to 5 nm, respectively. It is also observed that both the diffusion of germanium and the rate of oxidation are enhanced at 870 and 900 °C compared to equilibrium expectations. Transmission electron microscopy of a representative sample with secondary oxidation at 1080 °C for 20 min shows that the SiGe layer is crystalline in nature and seeded from the underlying silicon. Raman spectroscopy is used to determine residual strain in the SiGe region following secondary oxidation. The strain is compressive in nature and increases with Ge concentration to a maximum of approximately 1% in the samples probed. In order to elucidate the physical mechanisms, which govern the implantation-condensation process, we fit the experimental profiles of the samples with a model that uses a modified segregation boundary condition; a modified linear rate constant for the oxidation; and an enhanced diffusion coefficient of germanium where the

Germanium and uranium in coalified wood bom upper Devonian black shale

USGS Publications Warehouse

Breger, I.A.; Schopf, J.M.

1955-01-01

Microscopic study of black, vitreous, carbonaceous material occurring in the Chattanooga shale in Tennessee and in the Cleveland member of the Ohio shale in Ohio has revealed coalified woody plant tissue. Some samples have shown sufficient detail to be identified with the genus Cauixylon. Similar material has been reported in the literature as "bituminous" or "asphaltic" stringers. Spectrographic analyses of the ash from the coalified wood have shown unusually high percentages of germanium, uranium, vanadium, and nickel. The inverse relationship between uranium and germanium in the ash and the ash content of various samples shows an association of these elements with the organic constituents of the coal. On the basis of geochemical considerations, it seems most probable that the wood or coalified wood was germanium-bearing at the time logs or woody fragmenta were floated into the basins of deposition of the Chattanooga shale and the Cleveland member of the Ohio shale. Once within the marine environment, the material probably absorbed uranium with the formation of organo-uranium compounds such as exist in coals. It is suggested that a more systematic search for germaniferous coals in the vicinity of the Chattanooga shale and the Cleveland member of the Ohio shale might be rewarding. ?? 1955.

Germanium and uranium in coalified wood from Upper Devonian black shale

USGS Publications Warehouse

Breger, Irving A.; Schopf, James M.

1954-01-01

Microscopic study of black, vitreous, carbonaceous material occurring in the Chattanooga shale in Tennessee and in the Cleveland member of the Ohio shale in Ohio has revealed coalified woody plant tissue. Some samples have shown sufficient detail to be identified with the genus Callixylon. Similar material has been reported in the literature as "bituminous" or "asphaltic" stringers. Spectrographic analyses of the ash from the coalified wood have shown unusually high percentages of germanium, uranium, vanadium, and nickel. The inverse relationship between uranium and germanium in the ash and the ash content of various samples shows an association of these elements with the organic constituents of the coal. On the basis of geochemical considerations, it seems most probable that the wood or coalified wood was germanium-bearing at the time logs or woody fragments were floated into the basins of deposition of the Chattanooga shale and the Cleveland member of the Ohio shale. Once within the marine environment, the material probably absorbed uranium with the formation of organo-uranium compounds such as have been found to exist in coals. It is suggested that a more systematic search for germaniferous coals in the vicinity of the Chattanooga shale and the Cleveland member of the Ohio shale might be rewarding.

A Categorification of the Crystal Isomorphism B 1,1 B + B(Lambda i) = B(Lambdasigma (i) and a Graphical Calculus for the Shifted Symmetric Functions

NASA Astrophysics Data System (ADS)

Kvinge, Henry

We prove two results at the intersection of Lie theory and the representation theory of symmetric groups, Hecke algebras, and their generalizations. The first is a categorification of the crystal isomorphism B. (1,1) tensor B1,1 ⊕ B(Lambdai ) ≅ B(Lambdasigma (i)). Here B(Lambdai and B(Lambda sigma(i)) are two affine type highest weight crystals of weight Lambdai and Lambdasigma (i) respectively, sigma is a specific map from the Dynkin indexing set I to itself, and B1,1 is a Kirillov-Reshetikhin crystal. We show that this crystal isomorphism is in fact the shadow of a richer module-theoretic phenomenon in the representation theory of Khovanov-Lauda-Rouquier algebras of classical affine type. Our second result identifies the center EndH'( 1) of Khovanov's Heisenberg category H', as the algebra of shifted symmetric functions Lambda* of Okounkov and Olshanski, i.e. End H'(1) ≅ Lambda*. This isomorphism provides us with a graphical calculus for Lambda*. It also allows us to describe EndH'(1) in terms of the transition and co-transition measure of Kerov and the noncommutative probability spaces of Biane.

The low thermal gradient CZ technique as a way of growing of dislocation-free germanium crystals

NASA Astrophysics Data System (ADS)

Moskovskih, V. A.; Kasimkin, P. V.; Shlegel, V. N.; Vasiliev, Y. V.; Gridchin, V. A.; Podkopaev, O. I.

2014-09-01

This paper considers the possibility of growth of dislocation-free germanium single crystals. This is achieved by reducing the temperature gradients at the level of 1 K/cm and lower. Single germanium crystals 45-48 mm in diameter with a dislocation density of 102 cm-2 were grown by a Low Thermal Gradient Czochralski technique (LTG CZ).

Far-Infrared Magneto-Optical Studies in Germanium and Indium-Antimonide at High Intensities

NASA Astrophysics Data System (ADS)

Leung, Michael

Observations of nonlinear magneto-optical phenomena occurring in p-type Germanium and n-type Indium Antimonide are reported. These include multi-photon ionization of impurity states, and a new observation, the magneto-photon ionization of impurity states, and a new observation, the magneto-photon drag effect. A novel source of far-infrared radiation has been used. This source uses a pulsed CO(,2) LASER to optically pump a super-radiant cell, generating light with intensities up to 100 KW/cm('2) and wavelengths from 66 (mu)m to 496 (mu)m in a pulse of 150 nanoseconds duration. The Germanium samples were doped with Gallium, which is a shallow acceptor with an ionization potential of 11 meV. At liquid Helium temperature virtually all charge carriers are bound to acceptor sites. However, the high intensity radiation unexpectedly ionizes the acceptors. This is demonstrated through measurements of photoconductivity, transmission and the photo-Hall Effect. This observation is unexpected because the photon energy is one-fourth the ionization potential. Rate equations describing sequential multiphoton excitations are in agreement with the experimental results. The intermediate states are postulated to be acceptor exciton band states. Studies of the photoexcited mobility at 496 (mu)m suggest that at non-saturating levels of photoexcitation, the primary scattering mechanism of hot holes in Germanium is by neutral impurities. A new magneto-optical effect, the magneto-photon drag effect, has been studied in both Germanium and Indium Antimonide. This is simply the absorption of momentum by free carriers, from an incident photon field. It has been found that the mechanism for this effect is different in the two materials. In Germanium, the effect occurs when carriers make optical transitions from the heavy hole band to the light hole band. Thus, the magneto-optical behavior depends heavily upon the band structure. On the other hand, a modified Drude model (independent electron

Non-local electrical spin injection and detection in germanium at room temperature

NASA Astrophysics Data System (ADS)

Rortais, F.; Vergnaud, C.; Marty, A.; Vila, L.; Attané, J.-P.; Widiez, J.; Zucchetti, C.; Bottegoni, F.; Jaffrès, H.; George, J.-M.; Jamet, M.

2017-10-01

Non-local carrier injection/detection schemes lie at the very foundation of information manipulation in integrated systems. This paradigm consists in controlling with an external signal the channel where charge carriers flow between a "source" and a well separated "drain." The next generation electronics may operate on the spin of carriers in addition to their charge and germanium appears as the best hosting material to develop such a platform for its compatibility with mainstream silicon technology and the predicted long electron spin lifetime at room temperature. In this letter, we demonstrate injection of pure spin currents (i.e., with no associated transport of electric charges) in germanium, combined with non-local spin detection at 10 K and room temperature. For this purpose, we used a lateral spin valve with epitaxially grown magnetic tunnel junctions as spin injector and spin detector. The non-local magnetoresistance signal is clearly visible and reaches ≈15 mΩ at room temperature. The electron spin lifetime and diffusion length are 500 ps and 1 μm, respectively, the spin injection efficiency being as high as 27%. This result paves the way for the realization of full germanium spintronic devices at room temperature.

Determination of germanium by AAS in chloride-containing matrices.

PubMed

Anwari, M A; Abbasi, H U; Volkan, M; Ataman, O Y

1996-06-01

Interference effects of NaCl on the ET-AAS determination of Ge have been studied. The use of several matrix modifiers to alleviate this problem such as Ni and Zn perchlorates and nitrates, nitric acid, ammonium nitrate are reported. The stabilizing effect of Zn and Ni perchlorates allows the use of high pretreatment temperatures. NaCl is thus thermally volatilized from the atomizer by employing pretreatment temperatures higher than 1500 degrees C resulting in an improved sensitivity. Germanium levels in zinc plant slag samples, have been determined and compared to those obtained for the same samples spiked with NaCl with platform and wall atomization using nickel perchlorate as a matrix modifier. The results were compared with those from a hydride generation system equipped with a liquid nitrogen trap. The recoveries for germanium have been almost complete and amount to 99% for the original slag samples and 80% for 15% (w/w) NaCl containing spiked samples.

The microsomal metabolism of the organometallic derivatives of the group-IV elements, germanium, tin and lead.

PubMed Central

Prough, R A; Stalmach, M A; Wiebkin, P; Bridges, J W

1981-01-01

The NADPH- and oxygen-dependent microsomal metabolism of the di-, tri- and tetra-ethyl-substituted derivatives of germanium, tin and lead was shown to give rise to ethylene as a major product and ethane as a minor product. These reactions were shown to be catalysed by the liver microsomal cytochrome P-450-dependent mono-oxygenase. Since formation of ethane and ethylene was differentially inhibited by anaerobiosis, the results suggest that at least a large portion of the ethane produced may be derived by a reductive mechanism. Triethyltin bromide in both the absence and presence of NADPH was shown to convert cytochrome P-450 into cytochrome P-420 and to affect the function of the mono-oxygenase in vitro. Tetraethyltin caused the NADPH- and time-dependent formation of cytochrome P-420, suggesting that tetraethyltin is converted into triethyltin salts in significant concentrations. The order of potency in formation of cytochrome P-420 was closely paralleled by the ability of the tin derivatives to induce microsomal lipid peroxidation in vitro. PMID:7317015

Regimes of laser-induced periodic surface structure on germanium: radiation remnants and surface plasmons.

PubMed

Young, J F; Sipe, J E; van Driel, H M

1983-08-01

We present experimental evidence showing that the period of the rippled surface structure induced on germanium by 1.06-microm laser pulses undergoes a discontinuous shift above a certain threshold intensity. The measured shift, as a angle of incidence of the damaging beam, is quantitatively interpreted as a transition between a regime of inhomogeneous melting controlled by radiation-remnant field structures and a regime of ripple formation surface plasmons in an optically thick layer of liquid, metallic germanium formed at the surface.

Doping of germanium and silicon crystals with non-hydrogenic acceptors for far infrared lasers

DOEpatents

Haller, Eugene E.; Brundermann, Erik

2000-01-01

A method for doping semiconductors used for far infrared lasers with non-hydrogenic acceptors having binding energies larger than the energy of the laser photons. Doping of germanium or silicon crystals with beryllium, zinc or copper. A far infrared laser comprising germanium crystals doped with double or triple acceptor dopants permitting the doped laser to be tuned continuously from 1 to 4 terahertz and to operate in continuous mode. A method for operating semiconductor hole population inversion lasers with a closed cycle refrigerator.

Generating gradient germanium nanostructures by shock-induced amorphization and crystallization

DOE PAGES

Zhao, Shiteng; Kad, Bimal; Wehrenberg, Christopher E.; ...

2017-08-28

Gradient nanostructures are attracting considerable interest due to their potential to obtain superior structural and functional properties of materials. Applying powerful laser-driven shocks (stresses of up to one-third million atmospheres, or 33 gigapascals) to germanium, we report a complex gradient nanostructure consisting of, near the surface, nanocrystals with high density of nanotwins. Beyond there, the structure exhibits arrays of amorphous bands which are preceded by planar defects such as stacking faults generated by partial dislocations. At a lower shock stress, the surface region of the recovered target is completely amorphous. Here, we propose that germanium undergoes amorphization above a thresholdmore » stress and that the deformation-generated heat leads to nanocrystallization. These experiments are corroborated by molecular dynamics simulations which show that supersonic partial dislocation bursts play a role in triggering the crystalline-to-amorphous transition.« less

Generating gradient germanium nanostructures by shock-induced amorphization and crystallization

PubMed Central

Zhao, Shiteng; Kad, Bimal; Wehrenberg, Christopher E.; Remington, Bruce A.; Hahn, Eric N.; More, Karren L.; Meyers, Marc A.

2017-01-01

Gradient nanostructures are attracting considerable interest due to their potential to obtain superior structural and functional properties of materials. Applying powerful laser-driven shocks (stresses of up to one-third million atmospheres, or 33 gigapascals) to germanium, we report here a complex gradient nanostructure consisting of, near the surface, nanocrystals with high density of nanotwins. Beyond there, the structure exhibits arrays of amorphous bands which are preceded by planar defects such as stacking faults generated by partial dislocations. At a lower shock stress, the surface region of the recovered target is completely amorphous. We propose that germanium undergoes amorphization above a threshold stress and that the deformation-generated heat leads to nanocrystallization. These experiments are corroborated by molecular dynamics simulations which show that supersonic partial dislocation bursts play a role in triggering the crystalline-to-amorphous transition. PMID:28847926

Generating gradient germanium nanostructures by shock-induced amorphization and crystallization.

PubMed

Zhao, Shiteng; Kad, Bimal; Wehrenberg, Christopher E; Remington, Bruce A; Hahn, Eric N; More, Karren L; Meyers, Marc A

2017-09-12

Gradient nanostructures are attracting considerable interest due to their potential to obtain superior structural and functional properties of materials. Applying powerful laser-driven shocks (stresses of up to one-third million atmospheres, or 33 gigapascals) to germanium, we report here a complex gradient nanostructure consisting of, near the surface, nanocrystals with high density of nanotwins. Beyond there, the structure exhibits arrays of amorphous bands which are preceded by planar defects such as stacking faults generated by partial dislocations. At a lower shock stress, the surface region of the recovered target is completely amorphous. We propose that germanium undergoes amorphization above a threshold stress and that the deformation-generated heat leads to nanocrystallization. These experiments are corroborated by molecular dynamics simulations which show that supersonic partial dislocation bursts play a role in triggering the crystalline-to-amorphous transition.

Generating gradient germanium nanostructures by shock-induced amorphization and crystallization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Shiteng; Kad, Bimal; Wehrenberg, Christopher E.

Gradient nanostructures are attracting considerable interest due to their potential to obtain superior structural and functional properties of materials. Applying powerful laser-driven shocks (stresses of up to one-third million atmospheres, or 33 gigapascals) to germanium, we report a complex gradient nanostructure consisting of, near the surface, nanocrystals with high density of nanotwins. Beyond there, the structure exhibits arrays of amorphous bands which are preceded by planar defects such as stacking faults generated by partial dislocations. At a lower shock stress, the surface region of the recovered target is completely amorphous. Here, we propose that germanium undergoes amorphization above a thresholdmore » stress and that the deformation-generated heat leads to nanocrystallization. These experiments are corroborated by molecular dynamics simulations which show that supersonic partial dislocation bursts play a role in triggering the crystalline-to-amorphous transition.« less

Position resolution simulations for the inverted-coaxial germanium detector, SIGMA

NASA Astrophysics Data System (ADS)

Wright, J. P.; Harkness-Brennan, L. J.; Boston, A. J.; Judson, D. S.; Labiche, M.; Nolan, P. J.; Page, R. D.; Pearce, F.; Radford, D. C.; Simpson, J.; Unsworth, C.

2018-06-01

The SIGMA Germanium detector has the potential to revolutionise γ-ray spectroscopy, providing superior energy and position resolving capabilities compared with current large volume state-of-the-art Germanium detectors. The theoretical position resolution of the detector as a function of γ-ray interaction position has been studied using simulated detector signals. A study of the effects of RMS noise at various energies has been presented with the position resolution ranging from 0.33 mm FWHM at Eγ = 1 MeV, to 0.41 mm at Eγ = 150 keV. An additional investigation into the effects pulse alignment have on pulse shape analysis and in turn, position resolution has been performed. The theoretical performance of SIGMA operating in an experimental setting is presented for use as a standalone detector and as part of an ancillary system.

The MAJORANA DEMONSTRATOR: A search for neutrinoless double-beta decay of germanium-76

NASA Astrophysics Data System (ADS)

Schubert, Alexis; Majorana Collaboration

2011-04-01

Observation of neutrinoless double-beta decay (0 νββ) could determine whether the neutrino is a Majorana particle and may provide information on neutrino mass. The MAJORANA Collaboration will search for 0 νββ of 76Ge in an array of germanium detectors enriched to 86% in 76Ge. Germanium detectors are a well-understood technology and have the benefits of excellent energy resolution, a high Q-value, and the ability to act as source and detector. The p-type point contact germanium detectors chosen by the MAJORANA Collaboration provide low noise, low energy threshold, and some ability to distinguish between the signal and background events. MAJORANA is constructing the DEMONSTRATOR, which will be used to conduct research and development toward a tonne-scale Ge experiment. The DEMONSTRATOR will be installed deep underground and will contain 40 kg of Ge deployed in an ultra-low-background shielded environment. Research supported by DOE under contracts DE-AC05-00OR22725 and DE-FG02-97ER41020.

Ultrafast carrier thermalization and trapping in silicon-germanium alloy probed by extreme ultraviolet transient absorption spectroscopy

PubMed Central

Zürch, Michael; Chang, Hung-Tzu; Kraus, Peter M.; Cushing, Scott K.; Borja, Lauren J.; Gandman, Andrey; Kaplan, Christopher J.; Oh, Myoung Hwan; Prell, James S.; Prendergast, David; Pemmaraju, Chaitanya D.; Neumark, Daniel M.; Leone, Stephen R.

2017-01-01

Semiconductor alloys containing silicon and germanium are of growing importance for compact and highly efficient photonic devices due to their favorable properties for direct integration into silicon platforms and wide tunability of optical parameters. Here, we report the simultaneous direct and energy-resolved probing of ultrafast electron and hole dynamics in a silicon-germanium alloy with the stoichiometry Si0.25Ge0.75 by extreme ultraviolet transient absorption spectroscopy. Probing the photoinduced dynamics of charge carriers at the germanium M4,5-edge (∼30 eV) allows the germanium atoms to be used as reporter atoms for carrier dynamics in the alloy. The photoexcitation of electrons across the direct and indirect band gap into conduction band (CB) valleys and their subsequent hot carrier relaxation are observed and compared to pure germanium, where the Ge direct (ΔEgap,Ge,direct=0.8 eV) and Si0.25Ge0.75 indirect gaps (ΔEgap,Si0.25Ge0.75,indirect=0.95 eV) are comparable in energy. In the alloy, comparable carrier lifetimes are observed for the X, L, and Γ valleys in the conduction band. A midgap feature associated with electrons accumulating in trap states near the CB edge following intraband thermalization is observed in the Si0.25Ge0.75 alloy. The successful implementation of the reporter atom concept for capturing the dynamics of the electronic bands by site-specific probing in solids opens a route to study carrier dynamics in more complex materials with femtosecond and sub-femtosecond temporal resolution. PMID:28653020

Study of the effect of doping on the temperature stability of the optical properties of germanium single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podkopaev, O. I.; Shimanskiy, A. F., E-mail: shimanaf@mail.ru; Kopytkova, S. A.

2016-10-15

The effect of doping on the optical transmittance of germanium single crystals is studied by infrared Fourier spectroscopy. It is established that the introduction of silicon and tellurium additives into germanium doped with antimony provides a means for improving the temperature stability of the optical properties of the crystals.

A Low-Noise Germanium Ionization Spectrometer for Low-Background Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aalseth, Craig E.; Colaresi, Jim; Collar, Juan I.

2016-12-01

Recent progress on the development of very low energy threshold high purity germanium ionization spectrometers has produced an instrument of 1.2 kg mass and excellent noise performance. The detector was installed in a low-background cryostat intended for use in a low mass, WIMP dark matter direct detection search. The integrated detector and low background cryostat achieved noise performance of 98 eV full-width half-maximum of an input electronic pulse generator peak and gamma-ray energy resolution of 1.9 keV full-width half-maximum at the 60Co gamma-ray energy of 1332 keV. This Transaction reports the thermal characterization of the low-background cryostat, specifications of themore » newly prepared 1.2 kg p-type point contact germanium detector, and the ionization spectroscopy – energy resolution and energy threshold – performance of the integrated system.« less

Improved retention of phosphorus donors in germanium using a non-amorphizing fluorine co-implantation technique

NASA Astrophysics Data System (ADS)

Monmeyran, Corentin; Crowe, Iain F.; Gwilliam, Russell M.; Heidelberger, Christopher; Napolitani, Enrico; Pastor, David; Gandhi, Hemi H.; Mazur, Eric; Michel, Jürgen; Agarwal, Anuradha M.; Kimerling, Lionel C.

2018-04-01

Co-doping with fluorine is a potentially promising method for defect passivation to increase the donor electrical activation in highly doped n-type germanium. However, regular high dose donor-fluorine co-implants, followed by conventional thermal treatment of the germanium, typically result in a dramatic loss of the fluorine, as a result of the extremely large diffusivity at elevated temperatures, partly mediated by the solid phase epitaxial regrowth. To circumvent this problem, we propose and experimentally demonstrate two non-amorphizing co-implantation methods; one involving consecutive, low dose fluorine implants, intertwined with rapid thermal annealing and the second, involving heating of the target wafer during implantation. Our study confirms that the fluorine solubility in germanium is defect-mediated and we reveal the extent to which both of these strategies can be effective in retaining large fractions of both the implanted fluorine and, critically, phosphorus donors.

Comparison of ultrasonic-assisted and regular leaching of germanium from by-product of zinc metallurgy.

PubMed

Zhang, Libo; Guo, Wenqian; Peng, Jinhui; Li, Jing; Lin, Guo; Yu, Xia

2016-07-01

A major source of germanium recovery and also the source of this research is the by-product of lead and zinc metallurgical process. The primary purpose of the research is to investigate the effects of ultrasonic assisted and regular methods on the leaching yield of germanium from roasted slag containing germanium. In the study, the HCl-CaCl2 mixed solution is adopted as the reacting system and the Ca(ClO)2 used as the oxidant. Through six single factor (leaching time, temperature, amount of Ca(ClO)2, acid concentration, concentration of CaCl2 solution, ultrasonic power) experiments and the comparison of the two methods, it is found the optimum collective of germanium for ultrasonic-assisted method is obtained at temperature 80 °C for a leaching duration of 40 min. The optimum concentration for hydrochloric acid, CaCl2 and oxidizing agent are identified to be 3.5 mol/L, 150 g/L and 58.33 g/L, respectively. In addition, 700 W is the best ultrasonic power and an over-high power is adverse in the leaching process. Under the optimum condition, the recovery of germanium could reach up to 92.7%. While, the optimum leaching condition for regular leaching method is same to ultrasonic-assisted method, except regular method consume 100 min and the leaching rate of Ge 88.35% is lower about 4.35%. All in all, the experiment manifests that the leaching time can be reduced by as much as 60% and the leaching rate of Ge can be increased by 3-5% with the application of ultrasonic tool, which is mainly thanks to the mechanical action of ultrasonic. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of a high-purity germanium detector for small-animal SPECT

PubMed Central

Johnson, Lindsay C; Campbell, Desmond L; Hull, Ethan L; Peterson, Todd E

2011-01-01

We present an initial evaluation of a mechanically-cooled, high-purity germanium double-sided strip detector as a potential gamma camera for small-animal SPECT. It is 90 mm in diameter and 10 mm thick with two sets of 16 orthogonal strips that have a 4.5 mm width with a 5 mm pitch. We found an energy resolution of 0.96% at 140 keV, an intrinsic efficiency of 43.3% at 122 keV and a FWHM spatial resolution of approximately 1.5 mm. We demonstrated depth-of-interaction estimation capability through comparison of pinhole acquisitions with a point source on and off axis. Finally, a flood-corrected-flood image exhibited a strip-level uniformity of less than 1%. This high-purity germanium offers many desirable properties for small-animal SPECT. PMID:21852723

Characterization of a high-purity germanium detector for small-animal SPECT.

PubMed

Johnson, Lindsay C; Campbell, Desmond L; Hull, Ethan L; Peterson, Todd E

2011-09-21

We present an initial evaluation of a mechanically cooled, high-purity germanium double-sided strip detector as a potential gamma camera for small-animal SPECT. It is 90 mm in diameter and 10 mm thick with two sets of 16 orthogonal strips that have a 4.5 mm width with a 5 mm pitch. We found an energy resolution of 0.96% at 140 keV, an intrinsic efficiency of 43.3% at 122 keV and a FWHM spatial resolution of approximately 1.5 mm. We demonstrated depth-of-interaction estimation capability through comparison of pinhole acquisitions with a point source on and off axes. Finally, a flood-corrected flood image exhibited a strip-level uniformity of less than 1%. This high-purity germanium offers many desirable properties for small-animal SPECT.

Germanium Lift-Off Masks for Thin Metal Film Patterning

NASA Technical Reports Server (NTRS)

Brown, Ari

2012-01-01

A technique has been developed for patterning thin metallic films that are, in turn, used to fabricate microelectronics circuitry and thin-film sensors. The technique uses germanium thin films as lift-off masks. This requires development of a technique to strip or undercut the germanium chemically without affecting the deposited metal. Unlike in the case of conventional polymeric lift-off masks, the substrate can be exposed to very high temperatures during processing (sputter deposition). The reason why polymeric liftoff masks cannot be exposed to very high temperatures (greater than 100 C) is because (a) they can become cross linked, making lift-off very difficult if not impossible, and (b) they can outgas nitrogen and oxygen, which then can react with the metal being deposited. Consequently, this innovation is expected to find use in the fabrication of transition edge sensors and microwave kinetic inductance detectors, which use thin superconducting films deposited at high temperature as their sensing elements. Transition edge sensors, microwave kinetic inductance detectors, and their circuitry are comprised of superconducting thin films, for example Nb and TiN. Reactive ion etching can be used to pattern these films; however, reactive ion etching also damages the underlying substrate, which is unwanted in many instances. Polymeric lift-off techniques permit thin-film patterning without any substrate damage, but they are difficult to remove and the polymer can outgas during thin-film deposition. The outgassed material can then react with the film with the consequence of altered and non-reproducible materials properties, which, in turn, is deleterious for sensors and their circuitry. The purpose of this innovation was to fabricate a germanium lift-off mask to be used for patterning thin metal films.

Formation of Porous Germanium Layers by Silver-Ion Implantation

NASA Astrophysics Data System (ADS)

Stepanov, A. L.; Vorob'ev, V. V.; Nuzhdin, V. I.; Valeev, V. F.; Osin, Yu. N.

2018-04-01

We propose a method for the formation of porous germanium ( P-Ge) layers containing silver nanoparticles by means of high-dose implantation of low-energy Ag+ ions into single-crystalline germanium ( c-Ge). This is demonstrated by implantation of 30-keV Ag+ ions into a polished c-Ge plate to a dose of 1.5 × 1017 ion/cm2 at an ion beam-current density of 5 μA/cm2. Examination by high-resolution scanning electron microscopy (SEM), atomic-force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) microanalysis, and reflection high-energy electron diffraction (RHEED) showed that the implantation of silver ions into c-Ge surface led to the formation of a P-Ge layer with spongy structure comprising a network of interwoven nanofibers with an average diameter of ˜10-20 nm Ag nanoparticles on the ends of fibers. It is also established that the formation of pores during Ag+ ion implantation is accompanied by effective sputtering of the Ge surface.

Ultrafast carrier thermalization and trapping in silicon-germanium alloy probed by extreme ultraviolet transient absorption spectroscopy

DOE PAGES

Zürch, Michael; Chang, Hung-Tzu; Kraus, Peter M.; ...

2017-06-06

Semiconductor alloys containing silicon and germanium are of growing importance for compact and highly efficient photonic devices due to their favorable properties for direct integration into silicon platforms and wide tunability of optical parameters. Here, we report the simultaneous direct and energy-resolved probing of ultrafast electron and hole dynamics in a silicon-germanium alloy with the stoichiometry Si 0.25Ge 0.75 by extreme ultraviolet transient absorption spectroscopy. Probing the photoinduced dynamics of charge carriers at the germanium M 4,5-edge (~30 eV) allows the germanium atoms to be used as reporter atoms for carrier dynamics in the alloy. The photoexcitation of electrons acrossmore » the direct and indirect band gap into conduction band (CB) valleys and their subsequent hot carrier relaxation are observed and compared to pure germanium, where the Ge direct (ΔE gap,Ge,direct = 0.8 eV) and Si 0.25Ge 0.75 indirect gaps (ΔE gap,Si0.25Ge0.75,indirect = 0.95 eV) are comparable in energy. In the alloy, comparable carrier lifetimes are observed for the X, L, and Γ valleys in the conduction band. A midgap feature associated with electrons accumulating in trap states near the CB edge following intraband thermalization is observed in the Si 0.25Ge 0.75 alloy. The successful implementation of the reporter atom concept for capturing the dynamics of the electronic bands by site-specific probing in solids opens a route to study carrier dynamics in more complex materials with femtosecond and sub-femtosecond temporal resolution.« less

Ultrafast carrier thermalization and trapping in silicon-germanium alloy probed by extreme ultraviolet transient absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zürch, Michael; Chang, Hung-Tzu; Kraus, Peter M.

Semiconductor alloys containing silicon and germanium are of growing importance for compact and highly efficient photonic devices due to their favorable properties for direct integration into silicon platforms and wide tunability of optical parameters. Here, we report the simultaneous direct and energy-resolved probing of ultrafast electron and hole dynamics in a silicon-germanium alloy with the stoichiometry Si 0.25Ge 0.75 by extreme ultraviolet transient absorption spectroscopy. Probing the photoinduced dynamics of charge carriers at the germanium M 4,5-edge (~30 eV) allows the germanium atoms to be used as reporter atoms for carrier dynamics in the alloy. The photoexcitation of electrons acrossmore » the direct and indirect band gap into conduction band (CB) valleys and their subsequent hot carrier relaxation are observed and compared to pure germanium, where the Ge direct (ΔE gap,Ge,direct = 0.8 eV) and Si 0.25Ge 0.75 indirect gaps (ΔE gap,Si0.25Ge0.75,indirect = 0.95 eV) are comparable in energy. In the alloy, comparable carrier lifetimes are observed for the X, L, and Γ valleys in the conduction band. A midgap feature associated with electrons accumulating in trap states near the CB edge following intraband thermalization is observed in the Si 0.25Ge 0.75 alloy. The successful implementation of the reporter atom concept for capturing the dynamics of the electronic bands by site-specific probing in solids opens a route to study carrier dynamics in more complex materials with femtosecond and sub-femtosecond temporal resolution.« less

Using an isomorphic problem pair to learn introductory physics: Transferring from a two-step problem to a three-step problem

NASA Astrophysics Data System (ADS)

Lin, Shih-Yin; Singh, Chandralekha

2013-12-01

In this study, we examine introductory physics students’ ability to perform analogical reasoning between two isomorphic problems which employ the same underlying physics principles but have different surface features. 382 students from a calculus-based and an algebra-based introductory physics course were administered a quiz in the recitation in which they had to learn from a solved problem provided and take advantage of what they learned from it to solve another isomorphic problem (which we call the quiz problem). The solved problem provided has two subproblems while the quiz problem has three subproblems, which is known from previous research to be challenging for introductory students. In addition to the solved problem, students also received extra scaffolding supports that were intended to help them discern and exploit the underlying similarities of the isomorphic solved and quiz problems. The data analysis suggests that students had great difficulty in transferring what they learned from a two-step problem to a three-step problem. Although most students were able to learn from the solved problem to some extent with the scaffolding provided and invoke the relevant principles in the quiz problem, they were not necessarily able to apply the principles correctly. We also conducted think-aloud interviews with six introductory students in order to understand in depth the difficulties they had and explore strategies to provide better scaffolding. The interviews suggest that students often superficially mapped the principles employed in the solved problem to the quiz problem without necessarily understanding the governing conditions underlying each principle and examining the applicability of the principle in the new situation in an in-depth manner. Findings suggest that more scaffolding is needed to help students in transferring from a two-step problem to a three-step problem and applying the physics principles appropriately. We outline a few possible strategies

Probing the structural evolution of ruthenium doped germanium clusters: Photoelectron spectroscopy and density functional theory calculations

PubMed Central

Jin, Yuanyuan; Lu, Shengjie; Hermann, Andreas; Kuang, Xiaoyu; Zhang, Chuanzhao; Lu, Cheng; Xu, Hongguang; Zheng, Weijun

2016-01-01

We present a combined experimental and theoretical study of ruthenium doped germanium clusters, RuGen− (n = 3–12), and their corresponding neutral species. Photoelectron spectra of RuGen− clusters are measured at 266 nm. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) are obtained. Unbiased CALYPSO structure searches confirm the low-lying structures of anionic and neutral ruthenium doped germanium clusters in the size range of 3 ≤ n ≤ 12. Subsequent geometry optimizations using density functional theory (DFT) at PW91/LANL2DZ level are carried out to determine the relative stability and electronic properties of ruthenium doped germanium clusters. It is found that most of the anionic and neutral clusters have very similar global features. Although the global minimum structures of the anionic and neutral clusters are different, their respective geometries are observed as the low-lying isomers in either case. In addition, for n > 8, the Ru atom in RuGen−/0 clusters is absorbed endohedrally in the Ge cage. The theoretically predicted vertical and adiabatic detachment energies are in good agreement with the experimental measurements. The excellent agreement between DFT calculations and experiment enables a comprehensive evaluation of the geometrical and electronic structures of ruthenium doped germanium clusters. PMID:27439955

Dissolution chemistry and biocompatibility of silicon- and germanium-based semiconductors for transient electronics.

PubMed

Kang, Seung-Kyun; Park, Gayoung; Kim, Kyungmin; Hwang, Suk-Won; Cheng, Huanyu; Shin, Jiho; Chung, Sangjin; Kim, Minjin; Yin, Lan; Lee, Jeong Chul; Lee, Kyung-Mi; Rogers, John A

2015-05-06

Semiconducting materials are central to the development of high-performance electronics that are capable of dissolving completely when immersed in aqueous solutions, groundwater, or biofluids, for applications in temporary biomedical implants, environmentally degradable sensors, and other systems. The results reported here include comprehensive studies of the dissolution by hydrolysis of polycrystalline silicon, amorphous silicon, silicon-germanium, and germanium in aqueous solutions of various pH values and temperatures. In vitro cellular toxicity evaluations demonstrate the biocompatibility of the materials and end products of dissolution, thereby supporting their potential for use in biodegradable electronics. A fully dissolvable thin-film solar cell illustrates the ability to integrate these semiconductors into functional systems.

Shallow V-Shape Nanostructured Pit Arrays in Germanium Using Aqua Regia Electroless Chemical Etching

PubMed Central

Chaabane, Ibtihel; Banerjee, Debika; Touayar, Oualid; Cloutier, Sylvain G.

2017-01-01

Due to its high refractive index, reflectance is often a problem when using Germanium for optoelectronic devices integration. In this work, we propose an effective and low-cost nano-texturing method for considerably reducing the reflectance of bulk Germanium. To do so, uniform V-shape pit arrays are produced by wet electroless chemical etching in a 3:1 volume ratio of highly-concentrated hydrochloridric and nitric acids or so-called aqua regia bath using immersion times ranging from 5 to 60 min. The resulting pit morphology, the crystalline structure of the surface and the changes in surface chemistry after nano-patterning are all investigated. Finally, broadband near-infrared reflectance measurements confirm a significant reduction using this simple wet etching protocol, while maintaining a crystalline, dioxide-free, and hydrogen-passivated surface. It is important to mention that reflectance could be further reduced using deeper pits. However, most optoelectronic applications such as photodetectors and solar cells require relatively shallow patterning of the Germanium to allow formation of a pn-junction close to the surface. PMID:28773215

A Modified Monte Carlo Method for Carrier Transport in Germanium, Free of Isotropic Rates

NASA Astrophysics Data System (ADS)

Sundqvist, Kyle

2010-03-01

We present a new method for carrier transport simulation, relevant for high-purity germanium < 100 > at a temperature of 40 mK. In this system, the scattering of electrons and holes is dominated by spontaneous phonon emission. Free carriers are always out of equilibrium with the lattice. We must also properly account for directional effects due to band structure, but there are many cautions in the literature about treating germanium in particular. These objections arise because the germanium electron system is anisotropic to an extreme degree, while standard Monte Carlo algorithms maintain a reliance on isotropic, integrated rates. We re-examine Fermi's Golden Rule to produce a Monte Carlo method free of isotropic rates. Traditional Monte Carlo codes implement particle scattering based on an isotropically averaged rate, followed by a separate selection of the particle's final state via a momentum-dependent probability. In our method, the kernel of Fermi's Golden Rule produces analytical, bivariate rates which allow for the simultaneous choice of scatter and final state selection. Energy and momentum are automatically conserved. We compare our results to experimental data.

Cryogenic readout techniques for germanium detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benato, G.; Cattadori, C.; Di Vacri, A.

High Purity Germanium detectors are used in many applications, from nuclear and astro-particle physics, to homeland security or environment protection. Although quite standard configurations are often used, with cryostats, charge sensitive amplifiers and analog or digital acquisition systems all commercially available, it might be the case that a few specific applications, e.g. satellites, portable devices, cryogenic physics experiments, etc. also require the development of a few additional or complementary techniques. An interesting case is for sure GERDA, the Germanium Detector Array experiment, searching for neutrino-less double beta decay of {sup 76}Ge at the Gran Sasso National Laboratory of INFN -more » Italy. In GERDA the entire detector array, composed of semi-coaxial and BEGe naked crystals, is operated suspended inside a cryostat filled with liquid argon, that acts not only as cooling medium and but also as an active shield, thanks to its scintillation properties. These peculiar circumstances, together with the additional requirement of a very low radioactive background from all the materials adjacent to the detectors, clearly introduce significant constraints on the design of the Ge front-end readout electronics. All the Ge readout solutions developed within the framework of the GERDA collaboration, for both Phase I and Phase II, will be briefly reviewed, with their relative strength and weakness compared together and with respect to ideal Ge readout. Finally, the digital processing techniques developed by the GERDA collaboration for energy estimation of Ge detector signals will be recalled. (authors)« less

Thermodynamics of Alloys: Studies of Nickel-Gallium, Nickel-Germanium and Nickel-Rhodium Alloys.

DTIC Science & Technology

NICKEL ALLOYS, *GALLIUM ALLOYS, *GERMANIUM ALLOYS, * RHODIUM ALLOYS, *PHASE STUDIES, THERMODYNAMICS, INTERMETALLIC COMPOUNDS, FREE ENERGY, ENTROPY, HEAT OF FORMATION, CRYSTAL STRUCTURE, UNITED KINGDOM.

Research and Development Supporting a Next Generation Germanium Double Beta Decay Experiment

NASA Astrophysics Data System (ADS)

Rielage, Keith; Elliott, Steve; Chu, Pinghan; Goett, Johnny; Massarczyk, Ralph; Xu, Wenqin

2015-10-01

To improve the search for neutrinoless double beta decay, the next-generation experiments will increase in source mass and continue to reduce backgrounds in the region of interest. A promising technology for the next generation experiment is large arrays of Germanium p-type point contact detectors enriched in 76-Ge. The experience, expertise and lessons learned from the MAJORANA DEMONSTRATOR and GERDA experiments naturally lead to a number of research and development activities that will be useful in guiding a future experiment utilizing Germanium. We will discuss some R&D activities including a hybrid cryostat design, background reduction in cabling, connectors and electronics, and modifications to reduce assembly time. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

Rotational response of superconductors: Magnetorotational isomorphism and rotation-induced vortex lattice

NASA Astrophysics Data System (ADS)

Babaev, Egor; Svistunov, Boris

2014-03-01

The analysis of nonclassical rotational response of superfluids and superconductors was performed by Onsager [Onsager, Nuovo Cimento, Suppl. 6, 279 (1949), 10.1007/BF02780991] and London [Superfluids (Wiley, New York, 1950)] and crucially advanced by Feynman [Prog. Low Temp. Phys. 1, 17 (1955), 10.1016/S0079-6417(08)60077-3]. It was established that, in the thermodynamic limit, neutral superfluids rotate by forming—without any threshold—a vortex lattice. In contrast, the rotation of superconductors at angular frequency Ω—supported by uniform magnetic field BL∝Ω due to surface currents—is of the rigid-body type (London law). Here we show that, neglecting the centrifugal effects, the behavior of a rotating superconductor is identical to that of a superconductor placed in a uniform fictitious external magnetic field H ˜=-BL. In particular, the isomorphism immediately implies the existence of two critical rotational frequencies in type-2 superconductors.

Melting point of high-purity germanium stable isotopes

NASA Astrophysics Data System (ADS)

Gavva, V. A.; Bulanov, A. D.; Kut'in, A. M.; Plekhovich, A. D.; Churbanov, M. F.

2018-05-01

The melting point (Tm) of germanium stable isotopes 72Ge, 73Ge, 74Ge, 76Ge was determined by differential scanning calorimetry. With the increase in atomic mass of isotope the decrease in Tm is observed. The decrease was equal to 0.15 °C per the unit of atomic mass which qualitatively agrees with the value calculated by Lindemann formula accounting for the effect of "isotopic compression" of elementary cell.

Regulation of the demographic structure in isomorphic biphasic life cycles at the spatial fine scale.

PubMed

Vieira, Vasco Manuel Nobre de Carvalho da Silva; Mateus, Marcos Duarte

2014-01-01

Isomorphic biphasic algal life cycles often occur in the environment at ploidy abundance ratios (Haploid:Diploid) different from 1. Its spatial variability occurs within populations related to intertidal height and hydrodynamic stress, possibly reflecting the niche partitioning driven by their diverging adaptation to the environment argued necessary for their prevalence (evolutionary stability). Demographic models based in matrix algebra were developed to investigate which vital rates may efficiently generate an H:D variability at a fine spatial resolution. It was also taken into account time variation and type of life strategy. Ploidy dissimilarities in fecundity rates set an H:D spatial structure miss-fitting the ploidy fitness ratio. The same happened with ploidy dissimilarities in ramet growth whenever reproductive output dominated the population demography. Only through ploidy dissimilarities in looping rates (stasis, breakage and clonal growth) did the life cycle respond to a spatially heterogeneous environment efficiently creating a niche partition. Marginal locations were more sensitive than central locations. Related results have been obtained experimentally and numerically for widely different life cycles from the plant and animal kingdoms. Spore dispersal smoothed the effects of ploidy dissimilarities in fertility and enhanced the effects of ploidy dissimilarities looping rates. Ploidy dissimilarities in spore dispersal could also create the necessary niche partition, both over the space and time dimensions, even in spatial homogeneous environments and without the need for conditional differentiation of the ramets. Fine scale spatial variability may be the key for the prevalence of isomorphic biphasic life cycles, which has been neglected so far.

Regulation of the Demographic Structure in Isomorphic Biphasic Life Cycles at the Spatial Fine Scale

PubMed Central

Vieira, Vasco Manuel Nobre de Carvalho da Silva; Mateus, Marcos Duarte

2014-01-01

Isomorphic biphasic algal life cycles often occur in the environment at ploidy abundance ratios (Haploid:Diploid) different from 1. Its spatial variability occurs within populations related to intertidal height and hydrodynamic stress, possibly reflecting the niche partitioning driven by their diverging adaptation to the environment argued necessary for their prevalence (evolutionary stability). Demographic models based in matrix algebra were developed to investigate which vital rates may efficiently generate an H:D variability at a fine spatial resolution. It was also taken into account time variation and type of life strategy. Ploidy dissimilarities in fecundity rates set an H:D spatial structure miss-fitting the ploidy fitness ratio. The same happened with ploidy dissimilarities in ramet growth whenever reproductive output dominated the population demography. Only through ploidy dissimilarities in looping rates (stasis, breakage and clonal growth) did the life cycle respond to a spatially heterogeneous environment efficiently creating a niche partition. Marginal locations were more sensitive than central locations. Related results have been obtained experimentally and numerically for widely different life cycles from the plant and animal kingdoms. Spore dispersal smoothed the effects of ploidy dissimilarities in fertility and enhanced the effects of ploidy dissimilarities looping rates. Ploidy dissimilarities in spore dispersal could also create the necessary niche partition, both over the space and time dimensions, even in spatial homogeneous environments and without the need for conditional differentiation of the ramets. Fine scale spatial variability may be the key for the prevalence of isomorphic biphasic life cycles, which has been neglected so far. PMID:24658603

Active noise canceling system for mechanically cooled germanium radiation detectors

DOEpatents

Nelson, Karl Einar; Burks, Morgan T

2014-04-22

A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

Effect of the microstructure on electrical properties of high-purity germanium

NASA Astrophysics Data System (ADS)

Podkopaev, O. I.; Shimanskii, A. F.; Molotkovskaya, N. O.; Kulakovskaya, T. V.

2013-05-01

The interrelation between the electrical properties and the microstructure of high-purity germanium crystals has been revealed. The electrical conductivity of polycrystalline samples increases and the life-time of nonequilibrium charge carriers in them decreases with a decrease in the crystallite sizes.

Highly efficient periodically poled KTP-isomorphs with large apertures and extreme domain aspect-ratios

NASA Astrophysics Data System (ADS)

Canalias, Carlota; Zukauskas, Andrius; Tjörnhamman, Staffan; Viotti, Anne-Lise; Pasiskevicius, Valdas; Laurell, Fredrik

2018-02-01

Since the early 1990's, a substantial effort has been devoted to the development of quasi-phased-matched (QPM) nonlinear devices, not only in ferroelectric oxides like LiNbO3, LiTaO3 and KTiOPO4 (KTP), but also in semiconductors as GaAs, and GaP. The technology to implement QPM structures in ferroelectric oxides has by now matured enough to satisfy the most basic frequency-conversion schemes without substantial modification of the poling procedures. Here, we present a qualitative leap in periodic poling techniques that allows us to demonstrate devices and frequency conversion schemes that were deemed unfeasible just a few years ago. Thanks to our short-pulse poling and coercive-field engineering techniques, we are able to demonstrate large aperture (5 mm) periodically poled Rb-doped KTP devices with a highly-uniform conversion efficiency over the whole aperture. These devices allow parametric conversion with energies larger than 60 mJ. Moreover, by employing our coercive-field engineering technique we fabricate highlyefficient sub-µm periodically poled devices, with periodicities as short as 500 nm, uniform over 1 mm-thick crystals, which allow us to realize mirrorless optical parametric oscillators with counter-propagating signal and idler waves. These novel devices present unique spectral and tuning properties, superior to those of conventional OPOs. Furthermore, our techniques are compatible with KTA, a KTP isomorph with extended transparency in the mid-IR range. We demonstrate that our highly-efficient PPKTA is superior both for mid-IR and for green light generation - as a result of improved transmission properties in the visible range. Our KTP-isomorph poling techniques leading to highly-efficient QPM devices will be presented. Their optical performance and attractive damage thresholds will be discussed.

Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors

DOE PAGES

Aguayo, E.; Amman, M.; Avignone, F. T.; ...

2012-11-09

A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Furthermore, experiments that operate germanium detectors with a verymore » low energy threshold may benefit from the methods presented herein.« less

A crystalline germanium flexible thin-film transistor

NASA Astrophysics Data System (ADS)

Higashi, H.; Nakano, M.; Kudo, K.; Fujita, Y.; Yamada, S.; Kanashima, T.; Tsunoda, I.; Nakashima, H.; Hamaya, K.

2017-11-01

We experimentally demonstrate a flexible thin-film transistor (TFT) with (111)-oriented crystalline germanium (Ge) layers grown by a gold-induced crystallization method. Accumulation-mode metal source/drain p-channel Ge TFTs are fabricated on a polyimide film at ≤ 400 ° C . A field-effect mobility (μFE) of 10.7 cm2/Vs is obtained, meaning the highest μFE in the p-TFTs fabricated at ≤ 400 ° C on flexible plastic substrates. This study will lead to high-performance flexible electronics based on an inorganic-semiconductor channel.

Removal of the long-lived {sup 222}Rn daughters from steel and germanium surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wojcik, Marcin; Zuzel, Grzegorz; Majorovits, Bela

Removal of the long-lived {sup 222}Rn daughters ({sup 210}Pb, {sup 210}Bi and {sup 210}Po) from stainless steel and germanium surfaces was investigated. As cleaning technique etching was applied to samples in a form of discs exposed earlier to a strong radon source. Reduction of the {sup 210}Pb activity was tested using a HPGe spectrometer, for {sup 210}Bi a beta spectrometer and for {sup 210}Po an alpha spectrometer was used. According to the conducted measurements all the isotopes were removed very efficiently from germanium. Results obtained for stainless steel were worse but still better than those achieved for copper.

Intrinsic germanium detector used in borehole sonde for uranium exploration

USGS Publications Warehouse

Senftle, F.E.; Moxham, R.M.; Tanner, A.B.; Boynton, G.R.; Philbin, P.W.; Baicker, J.A.

1976-01-01

A borehole sonde (~1.7 m long; 7.3 cm diameter) using a 200 mm2 planar intrinsic germanium detector, mounted in a cryostat cooled by removable canisters of frozen propane, has been constructed and tested. The sonde is especially useful in measuring X- and low-energy gamma-ray spectra (40–400 keV). Laboratory tests in an artificial borehole facility indicate its potential for in-situ uranium analyses in boreholes irrespective of the state of equilibrium in the uranium series. Both natural gamma-ray and neutron-activation gamma-ray spectra have been measured with the sonde. Although the neutron-activation technique yields greater sensitivity, improvements being made in the resolution and efficiency of intrinsic germanium detectors suggest that it will soon be possible to use a similar sonde in the passive mode for measurement of uranium in a borehole down to about 0.1% with acceptable accuracy. Using a similar detector and neutron activation, the sonde can be used to measure uranium down to 0.01%.

Passivation of micro-strip gas chambers with an interstitial germanium coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyamoto, J.; Knoll, G.F.; Amos, N.

1996-12-31

Micro-strip gas chambers (MSGCs) were constructed in the Solid-State Electronics Laboratory of the University of Michigan and their performance was studied. Many efforts have been made in the past to construct MSGCs that yield high absolute gas gain and stable gas gain. Introducing a thin germanium layer has been effective for passivation but difficulties associated with the poor adhesiveness of the thin layer have been a serious obstacle. This paper reports on a new method used to overcome these difficulties. Unlike the conventional coating method the thin germanium layer was successfully deposited between the strip lines. This technique requires amore » careful geometric alignment of a second photomask with the original micro-strip structure. The resulting detector performance was noteworthy and an absolute gas gain of 2 {center_dot} 10{sup 4} was easily achieved by the new chamber. The chamber`s gain instability was also reduced significantly compared with those without interstitial coating.« less

MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection

DTIC Science & Technology

2012-09-01

MSM) photodectors fabricated using black silicon-germanium on silicon substrate (Si1–xGex//Si) for I-V, optical response, external quantum ...material for Si for many applications in low-power and high-speed semiconductor device technologies (4, 5). It is a promising material for quantum well ...MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection by Fred

Solution synthesis of germanium nanocrystals

DOEpatents

Gerung, Henry [Albuquerque, NM; Boyle, Timothy J [Kensington, MD; Bunge, Scott D [Cuyahoga Falls, OH

2009-09-22

A method for providing a route for the synthesis of a Ge(0) nanometer-sized material from. A Ge(II) precursor is dissolved in a ligand heated to a temperature, generally between approximately 100.degree. C. and 400.degree. C., sufficient to thermally reduce the Ge(II) to Ge(0), where the ligand is a compound that can bond to the surface of the germanium nanomaterials to subsequently prevent agglomeration of the nanomaterials. The ligand encapsulates the surface of the Ge(0) material to prevent agglomeration. The resulting solution is cooled for handling, with the cooling characteristics useful in controlling the size and size distribution of the Ge(0) materials. The characteristics of the Ge(II) precursor determine whether the Ge(0) materials that result will be nanocrystals or nanowires.

Gallium-doped germanium, evaluation of photoconductors, part 1

NASA Technical Reports Server (NTRS)

Moore, W. J.

1979-01-01

Gallium-doped germanium far infrared detectors were evaluated at low temperatures and low background simulating the space environment. Signal and noise characteristics were determined for detector temperatures in the 2K to 4K range. Optimum performance occurs at about 2.5K for all devices tested. The minimum average NEP in the 40-130 micron region was found to be approximately 4 x 10 to the minus 17th power watt Hz(-1/2) at a frequency of 1 Hz.

Induced Radioactivity Measured in a Germanium Detector After a Long Duration Balloon Flight

NASA Technical Reports Server (NTRS)

Starr, R.; Evans, L. G.; Floyed, S. R.; Drake, D. M.; Feldman, W. C.; Squyres, S. W.; Rester, A. C.

1997-01-01

A 13-day long duration balloon flight carrying a germanium detector was flown from Williams Field, Antartica in December 1992. After recovery of the payload the activity induced in the detector was measured.

Tunability of the dielectric function of heavily doped germanium thin films for mid-infrared plasmonics

NASA Astrophysics Data System (ADS)

Frigerio, Jacopo; Ballabio, Andrea; Isella, Giovanni; Sakat, Emilie; Pellegrini, Giovanni; Biagioni, Paolo; Bollani, Monica; Napolitani, Enrico; Manganelli, Costanza; Virgilio, Michele; Grupp, Alexander; Fischer, Marco P.; Brida, Daniele; Gallacher, Kevin; Paul, Douglas J.; Baldassarre, Leonetta; Calvani, Paolo; Giliberti, Valeria; Nucara, Alessandro; Ortolani, Michele

2016-08-01

Heavily doped semiconductor thin films are very promising for application in mid-infrared plasmonic devices because the real part of their dielectric function is negative and broadly tunable in the 5 to 50 μ m wavelength range at least. In this work, we investigate the electrodynamics of heavily n -type-doped germanium epilayers at infrared frequencies beyond the assumptions of the Drude model. The films are grown on silicon and germanium substrates, are in situ doped with phosphorous in the 1017 to 1019 cm-3 range, then screened plasma frequencies in the 100 to 1200 cm-1 range were observed. We employ infrared spectroscopy, pump-probe spectroscopy, and dc transport measurements to determine the tunability of the plasma frequency. Although no plasmonic structures have been realized in this work, we derive estimates of the decay time of mid-infrared plasmons and of their figures of merit for field confinement and for surface plasmon propagation. The average electron scattering rate increases almost linearly with excitation frequency, in agreement with quantum calculations based on a model of the ellipsoidal Fermi surface at the conduction band minimum of germanium accounting for electron scattering with optical phonons and charged impurities. Instead, we found weak dependence of plasmon losses on neutral impurity density. In films where a transient plasma was generated by optical pumping, we found significant dependence of the energy relaxation times in the few-picosecond range on the static doping level of the film, confirming the key but indirect role played by charged impurities in energy relaxation. Our results indicate that underdamped mid-infrared plasma oscillations are attained in n -type-doped germanium at room temperature.

Isomorphism and external support in conflicting institutional environments: a study of drug abuse treatment units.

PubMed

D'Aunno, T; Sutton, R I; Price, R H

1991-09-01

Using institutional theory, we developed predictions about organizational units that moved from an environment making consistent demands to one making conflicting demands. Many community mental health centers have diversified into drug abuse treatment. The units providing those services face conflicting demands from the traditional mental health sector and the new drug abuse treatment sector about which clients to serve, how to assess their problems, and who should provide treatment. We propose that in response to such demands these units will adopt apparently conflicting practices. Also, isomorphism with the traditional sector will be positively associated with external support from parent mental health centers and other actors in the mental health sector. Results generally support those predictions.

Salt

USGS Publications Warehouse

Franson, J.C.; Friend, M.

1999-01-01

Animals become victims of salt poisoning or toxicosis when toxic levels of sodium and chloride accumulate in the blood after they ingest large amounts of salt or, in some species, are deprived of water. For birds, salt sources may include saline water and road salt.Normally, the salt glands of birds (Fig. 47.1) excrete sodium and chloride to maintain the proper physiologic chemical balance. However, when there has been insufficient time for acclimation of the salt gland to the saline environment, or when salt gland function is compromised by exposure to certain pesticides or oil, the electrolyte balance of the blood may be upset by the excess sodium and chloride, resulting in toxicosis. Salt accumulation on the outside of the body, or salt encrustation, is a greater problem for waterbirds that use very saline waters than is salt toxicosis. Salt encrustation can lead to exertion, acute muscle degeneration, and eventual drowning during the struggle to escape entrapment.

Ge(14)[Ge(SiMe(3))(3)](5)Li(3)(THF)(6): the largest metalloid cluster compound of germanium: on the way to fullerene-like compounds?

PubMed

Schenk, Christian; Schnepf, Andreas

2008-10-14

The reaction of GeBr with LiGe(SiMe(3))(3) yields the largest metalloid cluster compound of germanium Ge(14)[Ge(SiMe(3))(3)](5)Li(3)(THF)(6), in which 14 germanium atoms are arranged as a hollow sphere in the cluster core, showing that in the case of germanium also fullerene-like compounds might be present in the borderland between the molecular and solid states.

The total switch time of silicon bipolar transistors with base doping gradients or with germanium gradients in the base

NASA Astrophysics Data System (ADS)

Karlsteen, M.; Willander, M.

1993-11-01

In this paper the total switch time for a transistor in a Direct Coupled Transistor Logic (DCTL) circuit is simulated by using Laplace transformations of the Ebers-Moll equations. The influence of doping gradients and germanium gradients in the base is investigated and their relative importance and their limitations are established. In a well designed bipolar transistor only a minor enhancement of the total switch time is obtained with the use of a doping gradient in the base. However, for bipolar transistors with base thickness over 500 Å, an improperly selected doping profile could be devastating for the total switch time. For a bipolar transistor the improvement of the total switch time due to a linear germanium gradient in the base could be up to about 30% compared with an ordinary silicon bipolar transistor. Still, a too high germanium gradient forces the normal transistor current gain (α N) to grow and the total switch time is thereby increased. Further enhancement could be achieved by the use of a second degree polynomial germanium profile in the base. Also in this case, care must be taken not to enlarge the germanium gradient too much as the total switch time then starts to increase. In all cases the betterment of the base transit time that is introduced by the electric field will not be directly used to reduce the base transit time. Instead the improvement is mostly used to lower the emitter transition charging time. However, the most important parameter to control is the normal transistor current gain (α N) that has to be kept within a narrow range to keep the total switch time low.

Regular Arrays of Germanium Nanoparticles Assisted by Thermoset Polymer Composites for High Capacity Lithium Ion Battery

NASA Astrophysics Data System (ADS)

Jo, Gyuha; Park, Moon Jeong

2012-02-01

In recent years Li-batteries have attracted significant interests for a variety of applications such as portable electronics and electric vehicle (EV) batteries due to their high energy densities. Key challenges in advancing the technology lie in specific energy density, the long term cycle properties, and durability at elevated temperature. In present study, we were motivated to prepare high capacity Li-battery by creating regular arrays of germanium nanoparticles (GeNPs, 1600 mAh/g) to replace commercial graphite anode (370 mAh/g). Thermoset polymers were employed to prepare GeNPs/polymer composites with tunable NP loadings and spacings, followed by carbonization process to prepare GeNPs/carbon composite anode material. Due to the large volume change of GeNPs with charge/discharge cycles, the regular arrays of GeNPs are turned out to be a crucial parameter in obtaining enhanced cyclability. The GeNPs/carbon anode materials were cycle tested in a half cell configuration using Lithium foil as a counter electrode and lithium salt doped PS-PEO block copolymers as electrolytes. High capacity and rate capability were achieved, which demonstrate the role of nano-sized and regularly-arrayed anode active materials in obtaining the improved battery performance.

Split Bull's eye shaped aluminum antenna for plasmon-enhanced nanometer scale germanium photodetector.

PubMed

Ren, Fang-Fang; Ang, Kah-Wee; Ye, Jiandong; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

2011-03-09

Bull's eye antennas are capable of efficiently collecting and concentrating optical signals into an ultrasmall area, offering an excellent solution to break the bottleneck between speed and photoresponse in subwavelength photodetectors. Here, we exploit the idea of split bull's eye antenna for a nanometer germanium photodetector operating at a standard communication wavelength of 1310 nm. The nontraditional plasmonic metal aluminum has been implemented in the resonant antenna structure fabricated by standard complementary metal-oxide-semiconductor (CMOS) processing. A significant enhancement in photoresponse could be achieved over the conventional bull's eye scheme due to an increased optical near-field in the active region. Moreover, with this novel antenna design the effective grating area could be significantly reduced without sacrificing device performance. This work paves the way for the future development of low-cost, high-density, and high-speed CMOS-compatible germanium-based optoelectronic devices.

Multiline phase conjugation at 4 microm in germanium.

PubMed

Depatie, D; Haueisen, D

1980-06-01

Phase conjugation by degenerate four-wave mixing in the 4-microm region in germanium has been observed for both single-line and multiline radiation. By using single-line output of a DF laser at 3.8 microm, X3 has been measured to be 4 X 10(-1) esu. Phase conjugation of multiline laser output has been achieved with an efficiency of 0.03%, a level that is consistent with the susceptibility found for single-line phase conjugation and the assumption of independent conjugation of each line of the multiline output.

Current experiments in germanium 0 ν β β search -- GERDA and MAJORANA

NASA Astrophysics Data System (ADS)

von Sturm, K.

2015-01-01

There are unanswered questions regarding neutrino physics that are of great interest for the scientific community. For example the absolute masses, the mass hierarchy and the nature of neutrinos are unknown up to now. The discovery of neutrinoless double beta decay (0νββ) would prove the existence of a Majorana mass, which would be linked to the half-life of the decay, and would in addition provide an elegant solution for the small mass of the neutrinos via the seesaw mechanism. Because of an existing discovery claim of 0νββ of 76Ge and the excellent energy resolution achievable, germanium is of special interest in the search for 0νββ . In this article the state of the art of germanium 0νββ search, namely the GERDA experiment and MAJORANA demonstrator, is presented. In particular, recent results of the GERDA collaboration, which strongly disfavour the above mentioned claim, are discussed.

Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium.

PubMed

Zürch, Michael; Chang, Hung-Tzu; Borja, Lauren J; Kraus, Peter M; Cushing, Scott K; Gandman, Andrey; Kaplan, Christopher J; Oh, Myoung Hwan; Prell, James S; Prendergast, David; Pemmaraju, Chaitanya D; Neumark, Daniel M; Leone, Stephen R

2017-06-01

Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and simultaneously observed by ultrafast transient absorption spectroscopy in the extreme ultraviolet at the germanium M 4,5 edge. We decompose the spectra into contributions of electronic state blocking and photo-induced band shifts at a carrier density of 8 × 10 20  cm -3 . Separate electron and hole relaxation times are observed as a function of hot carrier energies. A first-order electron and hole decay of ∼1 ps suggests a Shockley-Read-Hall recombination mechanism. The simultaneous observation of electrons and holes with extreme ultraviolet transient absorption spectroscopy paves the way for investigating few- to sub-femtosecond dynamics of both holes and electrons in complex semiconductor materials and across junctions.

Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium

PubMed Central

Zürch, Michael; Chang, Hung-Tzu; Borja, Lauren J.; Kraus, Peter M.; Cushing, Scott K.; Gandman, Andrey; Kaplan, Christopher J.; Oh, Myoung Hwan; Prell, James S.; Prendergast, David; Pemmaraju, Chaitanya D.; Neumark, Daniel M.; Leone, Stephen R.

2017-01-01

Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and simultaneously observed by ultrafast transient absorption spectroscopy in the extreme ultraviolet at the germanium M4,5 edge. We decompose the spectra into contributions of electronic state blocking and photo-induced band shifts at a carrier density of 8 × 1020 cm−3. Separate electron and hole relaxation times are observed as a function of hot carrier energies. A first-order electron and hole decay of ∼1 ps suggests a Shockley–Read–Hall recombination mechanism. The simultaneous observation of electrons and holes with extreme ultraviolet transient absorption spectroscopy paves the way for investigating few- to sub-femtosecond dynamics of both holes and electrons in complex semiconductor materials and across junctions. PMID:28569752

Detection of fallout 241Am in U.S. Atlantic salt marsh soils

NASA Astrophysics Data System (ADS)

Boyd, B. M.; Sommerfield, C. K.

2017-09-01

We report the presence of the fallout radionuclide 241Am (t1/2 = 433 years) in salt marsh soils from two U.S. Atlantic estuaries and discuss its utility as a particle tracer and geochronometer. This work is motivated by the knowledge that 137Cs, the most widely used geochronometer in environmental studies, will decay to extinction during the next century. At the same time, levels of 241Am, produced by radioactive decay of fallout 241Pu, will continue to increase on Earth's surface as they have since the height of atmospheric nuclear weapons testing in the 1960s. Measurements of 241Am in soils at eighteen salt marsh locations were made by non-destructive gamma spectrometry and compared to activities of 137Cs in the same samples. Results indicate that decay of fallout 241Pu can explain the presence of 241Am in the soils, and that the activities are sufficiently high to provide meaningful chronological information with acceptable confidence limits. We achieved a detection limit of 0.28-1.47 Bq kg-1 using low-energy, planar germanium detectors and 11-55 g powderized samples. Activities of 241Am (0.08-6.44 Bq kg-1) were similar in mineral- and organic-rich marsh soils indicating that soil composition does not appear to influence the initial capture of 241Pu and retention of its 241Am progeny. Given its high affinity for fine particles, long half-life, and ease of measurement by non-destructive gamma spectrometry, 241Am has potential to serve as an alternative to 137Cs geochronometry in salt marshes and perhaps other estuarine and coastal environments.

Multi-element germanium detectors for synchrotron applications

NASA Astrophysics Data System (ADS)

Rumaiz, A. K.; Kuczewski, A. J.; Mead, J.; Vernon, E.; Pinelli, D.; Dooryhee, E.; Ghose, S.; Caswell, T.; Siddons, D. P.; Miceli, A.; Baldwin, J.; Almer, J.; Okasinski, J.; Quaranta, O.; Woods, R.; Krings, T.; Stock, S.

2018-04-01

We have developed a series of monolithic multi-element germanium detectors, based on sensor arrays produced by the Forschungzentrum Julich, and on Application-specific integrated circuits (ASICs) developed at Brookhaven. Devices have been made with element counts ranging from 64 to 384. These detectors are being used at NSLS-II and APS for a range of diffraction experiments, both monochromatic and energy-dispersive. Compact and powerful readout systems have been developed, based on the new generation of FPGA system-on-chip devices, which provide closely coupled multi-core processors embedded in large gate arrays. We will discuss the technical details of the systems, and present some of the results from them.

Soft lithographic functionalization and patterning oxide-free silicon and germanium.

PubMed

Bowers, Carleen M; Toone, Eric J; Clark, Robert L; Shestopalov, Alexander A

2011-12-16

The development of hybrid electronic devices relies in large part on the integration of (bio)organic materials and inorganic semiconductors through a stable interface that permits efficient electron transport and protects underlying substrates from oxidative degradation. Group IV semiconductors can be effectively protected with highly-ordered self-assembled monolayers (SAMs) composed of simple alkyl chains that act as impervious barriers to both organic and aqueous solutions. Simple alkyl SAMs, however, are inert and not amenable to traditional patterning techniques. The motivation for immobilizing organic molecular systems on semiconductors is to impart new functionality to the surface that can provide optical, electronic, and mechanical function, as well as chemical and biological activity. Microcontact printing (μCP) is a soft-lithographic technique for patterning SAMs on myriad surfaces. Despite its simplicity and versatility, the approach has been largely limited to noble metal surfaces and has not been well developed for pattern transfer to technologically important substrates such as oxide-free silicon and germanium. Furthermore, because this technique relies on the ink diffusion to transfer pattern from the elastomer to substrate, the resolution of such traditional printing is essentially limited to near 1 μm. In contrast to traditional printing, inkless μCP patterning relies on a specific reaction between a surface-immobilized substrate and a stamp-bound catalyst. Because the technique does not rely on diffusive SAM formation, it significantly expands the diversity of patternable surfaces. In addition, the inkless technique obviates the feature size limitations imposed by molecular diffusion, facilitating replication of very small (<200 nm) features. However, up till now, inkless μCP has been mainly used for patterning relatively disordered molecular systems, which do not protect underlying surfaces from degradation. Here, we report a simple, reliable

Dosimetric properties of germanium doped calcium borate glass subjected to 6 MV and 10 MV X-ray irradiations

NASA Astrophysics Data System (ADS)

Tengku Kamarul Bahri, T. N. H.; Wagiran, H.; Hussin, R.; Saeed, M. A.; Hossain, I.; Ali, H.

2014-10-01

Germanium doped calcium borate glasses are investigated in term of thermoluminescence properties to seek their possibility to use as glass radiation dosimeter. The samples were exposed to 6 MV, and 10 MV photon beams in a dose range of 0.5-4.0 Gy. There is a single and broad thermoluminescence glow curve that exhibits its maximum intensity at about 300 °C. Linear dose response behavior has been found in this dose range for the both photon energies. Effective atomic number, TL sensitivity, and reproducibility have also been studied. It is found that the sensitivity of germanium doped sample at 6 MV is only 1.28% and it is superior to the sensitivity at 10 MV. The reproducibility of germanium doped sample is good with a percentage of relative error less than 10%. The results indicate that this glass has a potential to be used as a radiation dosimetry, especially for application in radiotherapy.

Temperature-Dependent Compensation and Optical Quenching by Thermal Oxygen Donors in Germanium

NASA Technical Reports Server (NTRS)

Watson, D.; Guptill, M.; Huffman, J.; Krabach, T.; Raines, S.

1994-01-01

Photothermal ionization spectroscopy of germanium, doped in the impurity-band conduction range with gallium acceptors and with thermal oxygen donors, reveals that the donors and acceptors compensate each other at temperatures higher than about 5K, but that the impurities coexist as neutral donors and acceptors at lower temperatures.

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100).

PubMed

Abidin, Mastura Shafinaz Zainal; Matsumura, Ryo; Anisuzzaman, Mohammad; Park, Jong-Hyeok; Muta, Shunpei; Mahmood, Mohamad Rusop; Sadoh, Taizoh; Hashim, Abdul Manaf

2013-11-06

We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm -1 corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm -1 corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.

Deformation potentials for band-to-band tunneling in silicon and germanium from first principles

NASA Astrophysics Data System (ADS)

Vandenberghe, William G.; Fischetti, Massimo V.

2015-01-01

The deformation potentials for phonon-assisted band-to-band tunneling (BTBT) in silicon and germanium are calculated using a plane-wave density functional theory code. Using hybrid functionals, we obtain: DTA = 4.1 × 108 eV/cm, DTO = 1.2 × 109 eV/cm, and DLO = 2.2 × 109 eV/cm for BTBT in silicon and DTA = 7.8 × 108 eV/cm and DLO = 1.3 × 109 eV/cm for BTBT in germanium. These values agree with experimentally measured values and we explain why in diodes, the TA/TO phonon-assisted BTBT dominates over LO phonon-assisted BTBT despite the larger deformation potential for the latter. We also explain why LO phonon-assisted BTBT can nevertheless dominate in many practical applications.

[Effects of germanium on cell growth, polysaccharide production and cellular redox status in suspension cultures of protocorm-like bodies of Dendrobium huoshanense].

PubMed

Wei, Ming; Yang, Chaoying; Jiang, Shaotong

2010-03-01

To solve the problem of low growth rate and metabolism level in suspension cultures of protocorm-like bodies (PLBs) of Dendrobium huoshanense. The effects of germanium on PLB proliferation and accumulation of polysaccharides together with nutrient utilization were investigated and the contents of reducing sugars, soluble proteins, the activities of antioxidant enzymes and redox status of the cells of PLB were analyzed. The results indicated that the optimum concentration of germanium dioxide (4.0 mg/L) significantly enhanced the cell growth and accumulation of polysaccharides, greatly improved contents of reducing sugars and soluble proteins, increased the activities of superoxide dismutase (SOD) and catalase (CAT) but decreased the activity of peroxidase(POD). The cell dry weight and production of polysaccharides were 32.6 g/L and 3.78 g/L, respectively. The analysis of cellular redox status showed that the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) in cells and the activity of glutathione reductase were significantly increased by the addition of germanium dioxide. The suitable concentration of germanium dioxide was beneficial to the cell growth and the accumulation of polysaccharides.

Low temperature solution synthesis of silicon, germanium and Si-Ge axial heterostructures in nanorod and nanowire form.

PubMed

Flynn, G; Stokes, K; Ryan, K M

2018-05-31

Herein, we report the formation of silicon, germanium and more complex Si-SixGe1-x and Si-Ge axial 1D heterostructures, at low temperatures in solution. These nanorods/nanowires are grown using phenylated compounds of silicon and germanium as reagents, with precursor decomposition achieved at substantially reduced temperatures (200 °C for single crystal nanostructures and 300 °C for heterostructures), through the addition of a reducing agent. This low energy route for the production of these functional nanostructures as a wet chemical in high yield is attractive to meet the processing needs for next generation photovoltaics, batteries and electronics.

Reduction of Defects in Germanium-Silicon

NASA Technical Reports Server (NTRS)

2003-01-01

Crystals grown without contact with a container have far superior quality to otherwise similar crystals grown in direct contact with a container. In addition to float-zone processing, detached- Bridgman growth is a promising tool to improve crystal quality, without the limitations of float zoning or the defects introduced by normal Bridgman growth. Goals of this project include the development of the detached Bridgman process to be reproducible and well understood and to quantitatively compare the defect and impurity levels in crystals grown by these three methods. Germanium (Ge) and germanium-silicon (Ge-Si) alloys are being used. At MSFC, we are responsible for the detached Bridgman experiments intended to differentiate among proposed mechanisms of detachment, and to confirm or refine our understanding of detachment. Because the contact angle is critical to determining the conditions for detachment, the sessile drop method was used to measure the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. Etch pit density (EPD) measurements of normal and detached Bridgman-grown Ge samples show a two order of magnitude improvement in the detached-grown samples. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. We have investigated the effects on detachment of ampoule material, pressure difference above and below the melt, and Si concentration; samples that are nearly completely detached can be grown repeatedly in pBN. Current work is concentrated on developing a

Silicon and Germanium (111) Surface Reconstruction

NASA Astrophysics Data System (ADS)

Hao, You Gong

Silicon (111) surface (7 x 7) reconstruction has been a long standing puzzle. For the last twenty years, various models were put forward to explain this reconstruction, but so far the problem still remains unsolved. Recent ion scattering and channeling (ISC), scanning tunneling microscopy (STM) and transmission electron diffraction (TED) experiments reveal some new results about the surface which greatly help investigators to establish better models. This work proposes a silicon (111) surface reconstruction mechanism, the raising and lowering mechanism which leads to benzene -like ring and flower (raised atom) building units. Based on these building units a (7 x 7) model is proposed, which is capable of explaining the STM and ISC experiment and several others. Furthermore the building units of the model can be used naturally to account for the germanium (111) surface c(2 x 8) reconstruction and other observed structures including (2 x 2), (5 x 5) and (7 x 7) for germanium as well as the (/3 x /3)R30 and (/19 x /19)R23.5 impurity induced structures for silicon, and the higher temperature disordered (1 x 1) structure for silicon. The model is closely related to the silicon (111) surface (2 x 1) reconstruction pi-bonded chain model, which is the most successful model for the reconstruction now. This provides an explanation for the rather low conversion temperature (560K) of the (2 x 1) to the (7 x 7). The model seems to meet some problems in the explanation of the TED result, which is explained very well by the dimer, adatom and stacking fault (DAS) model proposed by Takayanagi. In order to explain the TED result, a variation of the atomic scattering factor is proposed. Comparing the benzene-like ring model with the DAS model, the former needs more work to explain the TED result and the later has to find a way to explain the silicon (111) surface (1 x 1) disorder experiment.

Chiral nematic porous germania and germanium/carbon films

NASA Astrophysics Data System (ADS)

Xu, Jing; Nguyen, Thanh-Dinh; Xie, Kai; Hamad, Wadood Y.; MacLachlan, Mark J.

2015-07-01

We report our extensive attempts and, ultimately, success to produce crack-free, chiral nematic GeO2/cellulose nanocrystal (CNC) composite films with tunable photonic properties from the controlled assembly of germanium(iv) alkoxides with the lyotropic liquid-crystalline CNCs in a mixed solvent of water/DMF. With different pyrolysis conditions, the photonic GeO2/CNC composites can be converted into freestanding chiral nematic films of amorphous GeO2, and semiconducting mesoporous GeO2/C and Ge/C replicas. These new materials are promising for chiral separation, enantioselective adsorption, catalysis, sensing, optoelectronics, and lithium ion batteries. Furthermore, the new, reproducible synthesis strategies developed may be applicable for constructing other composites and porous materials with chiral nematic ordering.We report our extensive attempts and, ultimately, success to produce crack-free, chiral nematic GeO2/cellulose nanocrystal (CNC) composite films with tunable photonic properties from the controlled assembly of germanium(iv) alkoxides with the lyotropic liquid-crystalline CNCs in a mixed solvent of water/DMF. With different pyrolysis conditions, the photonic GeO2/CNC composites can be converted into freestanding chiral nematic films of amorphous GeO2, and semiconducting mesoporous GeO2/C and Ge/C replicas. These new materials are promising for chiral separation, enantioselective adsorption, catalysis, sensing, optoelectronics, and lithium ion batteries. Furthermore, the new, reproducible synthesis strategies developed may be applicable for constructing other composites and porous materials with chiral nematic ordering. Electronic supplementary information (ESI) available: TGA, IR, Raman, TEM, SEM, BET. See DOI: 10.1039/c5nr02520f

Optical properties of highly n-doped germanium obtained by in situ doping and laser annealing

NASA Astrophysics Data System (ADS)

Frigerio, J.; Ballabio, A.; Gallacher, K.; Giliberti, V.; Baldassarre, L.; Millar, R.; Milazzo, R.; Maiolo, L.; Minotti, A.; Bottegoni, F.; Biagioni, P.; Paul, D.; Ortolani, M.; Pecora, A.; Napolitani, E.; Isella, G.

2017-11-01

High n-type doping in germanium is essential for many electronic and optoelectronic applications especially for high performance Ohmic contacts, lasing and mid-infrared plasmonics. We report on the combination of in situ doping and excimer laser annealing to improve the activation of phosphorous in germanium. An activated n-doping concentration of 8.8  ×  1019 cm-3 has been achieved starting from an incorporated phosphorous concentration of 1.1  ×  1020 cm-3. Infrared reflectivity data fitted with a multi-layer Drude model indicate good uniformity over a 350 nm thick layer. Photoluminescence demonstrates clear bandgap narrowing and an increased ratio of direct to indirect bandgap emission confirming the high doping densities achieved.

Surface-enhanced infrared spectroscopic studies of the catalytic behavior of silver nanoparticles on a germanium substrate.

PubMed

Liou, Yen-Chen Maggie; Yang, Jyisy; Fasasi, Ayuba; Griffiths, Peter R

2011-05-01

The catalytic activity of silver nanoparticles (AgNPs) on a germanium substrate is reported. Para-nitrothiophenol (pNTP) that had been adsorbed on this substrate is converted to p-aminothiophenol (pATP) under very mild reaction conditions, such as simply soaking in water. The AgNPs may be formed either by physical vapor deposition or by electroless deposition from a solution of silver nitrate. Analogous reactions were not observed on copper nanoparticles on germanium or AgNPs on silicon or zinc selenide even though very slow conversion of pNTP to pATP was observed with Au nanoparticles (AuNPs) on Ge under controlled reaction conditions. The effects of factors that could influence the catalytic reaction were examined; these included the particle size of the AgNPs, reaction temperature, concentration and chemical nature of other ions present in the solution, the pH of the water, and the nature of the substrate. The reaction rate was approximately independent of the particle size for AgNPs between 50 and 150 nm in diameter. Increasing the temperature accelerates the reaction significantly; at temperatures above 40 °C, the adsorbed pNTP is completely converted by water within five minutes. Not surprisingly, the reaction rate was increased as the pH of the solution was decreased, as the reduction of each nitro group to an amino group requires six protons. The presence of Br(-) and I(-) ions accelerated the reaction to the point that even at 4 °C, the conversion of the nitro group was still observable, while solutions containing chloride ions had to be heated to 40 °C before their effect became apparent. Apparently, Br(-) and I(-) ions remove the oxide layer from the surface of the germanium substrate, facilitating transfer of electrons from the germanium to the nitro group of the pNTP.

Determining orbital particle parameters of impacts into germanium using morphology analysis and calibration data from hypervelocity impact experiments in the laboratory

NASA Technical Reports Server (NTRS)

Paul, Klaus G.

1995-01-01

This paper describes the work that is done at the Lehrstuhl fur Raumfahrttechnik (lrt) at the Technische Universitat Munchen to examine particle impacts into germanium surfaces which were flown on board the LDEF satellite. Besides the description of the processing of the samples, a brief overview of the particle launchers at our institute is given together with descriptions of impact morphology of high- and hypervelocity particles into germanium. Since germanium is a brittle, almost glass-like material, the impact morphology may also be interesting for anyone dealing with materials such as optics and solar cells. The main focus of our investigations is to learn about the impacting particle's properties, for example mass, velocity and direction. This is done by examining the morphology, various geometry parameters, crater obliqueness and crater volume.

Investigation of germanium quantum-well light sources.

PubMed

Fei, Edward T; Chen, Xiaochi; Zang, Kai; Huo, Yijie; Shambat, Gary; Miller, Gerald; Liu, Xi; Dutt, Raj; Kamins, Theodore I; Vuckovic, Jelena; Harris, James S

2015-08-24

In this paper, we report a broad investigation of the optical properties of germanium (Ge) quantum-well devices. Our simulations show a significant increase of carrier density in the Ge quantum wells. Photoluminescence (PL) measurements show the enhanced direct-bandgap radiative recombination rates due to the carrier density increase in the Ge quantum wells. Electroluminescence (EL) measurements show the temperature-dependent properties of our Ge quantum-well devices, which are in good agreement with our theoretical models. We also demonstrate the PL measurements of Ge quantum-well microdisks using tapered-fiber collection method and quantify the optical loss of the Ge quantum-well structure from the measured PL spectra for the first time.

Zero-bias 40Gbit/s germanium waveguide photodetector on silicon.

PubMed

Vivien, Laurent; Polzer, Andreas; Marris-Morini, Delphine; Osmond, Johann; Hartmann, Jean Michel; Crozat, Paul; Cassan, Eric; Kopp, Christophe; Zimmermann, Horst; Fédéli, Jean Marc

2012-01-16

We report on lateral pin germanium photodetectors selectively grown at the end of silicon waveguides. A very high optical bandwidth, estimated up to 120GHz, was evidenced in 10 µm long Ge photodetectors using three kinds of experimental set-ups. In addition, a responsivity of 0.8 A/W at 1550 nm was measured. An open eye diagrams at 40Gb/s were demonstrated under zero-bias at a wavelength of 1.55 µm.

Size-Tunable Photothermal Germanium Nanocrystals.

PubMed

Sun, Wei; Zhong, Grace; Kübel, Christian; Jelle, Abdinoor A; Qian, Chenxi; Wang, Lu; Ebrahimi, Manuchehr; Reyes, Laura M; Helmy, Amr S; Ozin, Geoffrey A

2017-05-22

Germanium nanocrystals (ncGe) have not received as much attention as silicon nanocrystals (ncSi). However, Ge has demonstrated superiority over Si nanomaterials in some applications. Examples include, high charge-discharge rate lithium-ion batteries, small band-gap opto-electronic devices, and photo-therapeutics. When stabilized in an oxide matrix (ncGe/GeO x ), its high charge-retention has enabled non-volatile memories. It has also found utility as a high-capacity anode material for Li-ion batteries with impressive stability. Herein, we report an organic-free synthesis of size-controlled ncGe in a GeO x matrix as well as freestanding ncGe, via the thermal disproportionation of GeO prepared from thermally induced dehydration of Ge(OH) 2 . The photothermal effect of ncGe, quantified by Raman spectroscopy, is found to be size dependent and superior to ncSi. This advance suggests applications of ncGe in photothermal therapy, desalination, and catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extreme ultraviolet probing of nonequilibrium dynamics in high energy density germanium

NASA Astrophysics Data System (ADS)

Principi, E.; Giangrisostomi, E.; Mincigrucci, R.; Beye, M.; Kurdi, G.; Cucini, R.; Gessini, A.; Bencivenga, F.; Masciovecchio, C.

2018-05-01

Intense femtosecond infrared laser pulses induce a nonequilibrium between thousands of Kelvin hot valence electrons and room-temperature ions in a germanium sample foil. The evolution of this exotic state of matter is monitored with time-resolved extreme ultraviolet absorption spectroscopy across the Ge M2 ,3 edge (≃30 eV ) using the FERMI free-electron laser. We analyze two distinct regimes in the ultrafast dynamics in laser-excited Ge: First, on a subpicosecond time scale, the electron energy distribution thermalizes to an extreme temperature unreachable in equilibrium solid germanium; then, during the following picoseconds, the lattice reacts strongly altering the electronic structure and resulting in melting to a metallic state alongside a breakdown of the local atomic order. Data analysis, based on a hybrid approach including both numerical and analytical calculations, provides an estimation of the electron and ion temperatures, the electron density of states, the carrier-phonon relaxation time, as well as the carrier density and lattice heat capacity under those extreme nonequilibrium conditions. Related structural anomalies, such as the occurrence of a transient low-density liquid phase and the possible drop in lattice heat capacity are discussed.

Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium

DOE PAGES

Zurch, Michael; Chang, Hung -Tzu; Borja, Lauren J.; ...

2017-06-01

Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and simultaneously observed by ultrafast transient absorption spectroscopy in the extreme ultraviolet at the germanium M 4,5 edge. We decompose the spectra into contributions of electronic state blocking and photo-induced band shifts at a carrier density of 8 × 10 20 cm –3. Separate electron and hole relaxation times are observedmore » as a function of hot carrier energies. A first-order electron and hole decay of ~1 ps suggests a Shockley–Read–Hall recombination mechanism. Furthermore, the simultaneous observation of electrons and holes with extreme ultraviolet transient absorption spectroscopy paves the way for investigating few- to sub-femtosecond dynamics of both holes and electrons in complex semiconductor materials and across junctions.« less

Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zurch, Michael; Chang, Hung -Tzu; Borja, Lauren J.

Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and simultaneously observed by ultrafast transient absorption spectroscopy in the extreme ultraviolet at the germanium M 4,5 edge. We decompose the spectra into contributions of electronic state blocking and photo-induced band shifts at a carrier density of 8 × 10 20 cm –3. Separate electron and hole relaxation times are observedmore » as a function of hot carrier energies. A first-order electron and hole decay of ~1 ps suggests a Shockley–Read–Hall recombination mechanism. Furthermore, the simultaneous observation of electrons and holes with extreme ultraviolet transient absorption spectroscopy paves the way for investigating few- to sub-femtosecond dynamics of both holes and electrons in complex semiconductor materials and across junctions.« less

Continuously tunable photonic fractional Hilbert transformer using a high-contrast germanium-doped silica-on-silicon microring resonator.

PubMed

Shahoei, Hiva; Dumais, Patrick; Yao, Jianping

2014-05-01

We propose and experimentally demonstrate a continuously tunable fractional Hilbert transformer (FHT) based on a high-contrast germanium-doped silica-on-silicon (SOS) microring resonator (MRR). The propagation loss of a high-contrast germanium-doped SOS waveguide can be very small (0.02 dB/cm) while the lossless bend radius can be less than 1 mm. These characteristics lead to the fabrication of an MRR with a high Q-factor and a large free-spectral range (FSR), which is needed to implement a Hilbert transformer (HT). The SOS MRR is strongly polarization dependent. By changing the polarization direction of the input signal, the phase shift introduced at the center of the resonance spectrum is changed. The tunable phase shift at the resonance wavelength can be used to implement a tunable FHT. A germanium-doped SOS MRR with a high-index contrast of 3.8% is fabricated. The use of the fabricated MRR for the implementation of a tunable FHT with tunable orders at 1, 0.85, 0.95, 1.05, and 1.13 for a Gaussian pulse with the temporal full width at half-maximum of 80 ps is experimentally demonstrated.

Germanium detectors for nuclear spectroscopy: Current research and development activity at LNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Napoli, D. R., E-mail: daniel.r.napoli@lnl.infn.it; Maggioni, G., E-mail: maggioni@lnl.infn.it; Carturan, S.

2016-07-07

High-purity Germanium (HPGe) detectors have reached an unprecedented level of sophistication and are still the best solution for high-resolution gamma spectroscopy. In the present work, we will show the results of the characterization of new surface treatments for the production of these detectors, studied in the framework of our multidisciplinary research program in HPGe detector technologies.

US-ROK Action Sheet 34: Safeguards Application of a Hand-held Mechanically Cooled Germanium Spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dreyer, J.; Burks, M.; Ham, Y.

2015-10-20

This report summarizes results of Action Sheet 34 - for the cooperative efforts on the field testing and evaluation of a high-resolution, hand-held, gamma-ray spectrometer, known as SPG (Spectroscopic Planar Germanium), for safeguards application such as short notice inspections, UF6 analysis, enrichment determination, and other potential applications. The Spectroscopic Planar Germanium (SPG) has been demonstrated IAEA Physical Inventory Verification (PIV) in South Korea. This field test was a success and the feedback provided by KINAC, IAEA, and national laboratory staff was used to direct efforts to improve the instrument this year. Key points in this report include measurement results frommore » PIV, analysis of spectra with commercially available Ortec U235 and PC-FRAM, and completion of tripod and tungsten collimator and integration of user feedback.« less

High-capacity nanostructured germanium-containing materials and lithium alloys thereof

DOEpatents

Graetz, Jason A.; Fultz, Brent T.; Ahn, Channing; Yazami, Rachid

2010-08-24

Electrodes comprising an alkali metal, for example, lithium, alloyed with nanostructured materials of formula Si.sub.zGe.sub.(z-1), where 0germanium exhibit a combination of improved capacities, cycle lives, and/or cycling rates compared with similar electrodes made from graphite. These electrodes are useful as anodes for secondary electrochemical cells, for example, batteries and electrochemical supercapacitors.

Mapping the electromagnetic field confinement in the gap of germanium nanoantennas with plasma wavelength of 4.5 micrometers

NASA Astrophysics Data System (ADS)

Calandrini, Eugenio; Venanzi, Tommaso; Appugliese, Felice; Badioli, Michela; Giliberti, Valeria; Baldassarre, Leonetta; Biagioni, Paolo; De Angelis, Francesco; Klesse, Wolfgang M.; Scappucci, Giordano; Ortolani, Michele

2016-09-01

We study plasmonic nanoantennas for molecular sensing in the mid-infrared made of heavily doped germanium, epitaxially grown with a bottom-up doping process and featuring free carrier density in excess of 1020 cm-3. The dielectric function of the 250 nm thick germanium film is determined, and bow-tie antennas are designed, fabricated, and embedded in a polymer. By using a near-field photoexpansion mapping technique at λ = 5.8 μm, we demonstrate the existence in the antenna gap of an electromagnetic energy density hotspot of diameter below 100 nm and confinement volume 105 times smaller than λ3.

The isotope composition of inorganic germanium in seawater and deep sea sponges

NASA Astrophysics Data System (ADS)

Guillermic, Maxence; Lalonde, Stefan V.; Hendry, Katharine R.; Rouxel, Olivier J.

2017-09-01

Although dissolved concentrations of germanium (Ge) and silicon (Si) in modern seawater are tightly correlated, uncertainties still exist in the modern marine Ge cycle. Germanium stable isotope systematics in marine systems should provide additional constraints on marine Ge sources and sinks, however the low concentration of Ge in seawater presents an analytical challenge for isotopic measurement. Here, we present a new method of pre-concentration of inorganic Ge from seawater which was applied to measure three Ge isotope profiles in the Southern Ocean and deep seawater from the Atlantic and Pacific Oceans. Germanium isotopic measurements were performed on Ge amounts as low as 2.6 ng using a double-spike approach and a hydride generation system coupled to a MC-ICP-MS. Germanium was co-precipitated with iron hydroxide and then purified through anion-exchange chromatography. Results for the deep (i.e. >1000 m depth) Pacific Ocean off Hawaii (nearby Loihi Seamount) and the deep Atlantic off Bermuda (BATS station) showed nearly identical δ74/70Ge values at 3.19 ± 0.31‰ (2SD, n = 9) and 2.93 ± 0.10‰ (2SD, n = 2), respectively. Vertical distributions of Ge concentration and isotope composition in the deep Southern Ocean for water depth > 1300 m yielded an average δ74/70Ge = 3.13 ± 0.25‰ (2SD, n = 14) and Ge/Si = 0.80 ± 0.09 μmol/mol (2SD, n = 12). Significant variations in δ74/70Ge, from 2.62 to 3.71‰, were measured in the first 1000 m in one station of the Southern Ocean near Sars Seamount in the Drake Passage, with the heaviest values measured in surface waters. Isotope fractionation by diatoms during opal biomineralization may explain the enrichment in heavy isotopes for both Ge and Si in surface seawater. However, examination of both oceanographic parameters and δ74/70Ge values suggest also that water mass mixing and potential contribution of shelf-derived Ge also could contribute to the variations. Combining these results with new Ge isotope data

Liking, salt taste perception and use of table salt when consuming reduced-salt chicken stews in light of South Africa's new salt regulations.

PubMed

De Kock, H L; Zandstra, E H; Sayed, N; Wentzel-Viljoen, E

2016-01-01

This study investigated the impact of salt reduction on liking, salt taste perception, and use of table salt when consuming chicken stew in light of South Africa's new salt recommendations. In total, 432 South-African consumers (aged 35.2 ± 12.3 years) consumed a full portion of a chicken stew meal once at a central location. Four stock cube powders varying in salt content were used to prepare chicken stews: 1) no reduction - 2013 Na level; regular salt level as currently available on the South African market (24473 mg Na/100 g), 2) salt reduction smaller than 2016 level, i.e. 10%-reduced (22025 mg Na/100 g), 3) 2016 salt level, as per regulatory prescriptions (18000 mg Na/100 g), 4) 2019 salt level, as per regulatory prescriptions (13000 mg Na/100 g). Consumers were randomly allocated to consume one of the four meals. Liking, salt taste perception, and use of table salt and pepper were measured. Chicken stews prepared with reduced-salt stock powders were equally well-liked as chicken stews with the current salt level. Moreover, a gradual reduction of the salt in the chicken stews resulted in a reduced salt intake, up to an average of 19% for the total group compared to the benchmark 2013 Na level stew. However, 19% of consumers compensated by adding salt back to full compensation in some cases. More salt was added with increased reductions of salt in the meals, even to the point of full compensation. Further investigation into the impacts of nutrition communication and education about salt reduction on salt taste perception and use is needed. This research provides new consumer insights on salt use and emphasises the need for consumer-focused behaviour change approaches, in addition to reformulation of products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sea Salt vs. Table Salt: What's the Difference?

MedlinePlus

... Nutrition and healthy eating What's the difference between sea salt and table salt? Answers from Katherine Zeratsky, R.D., L.D. The main differences between sea salt and table salt are in their taste, ...

Multi-element germanium detectors for synchrotron applications

DOE PAGES

Rumaiz, A. K.; Kuczewski, A. J.; Mead, J.; ...

2018-04-27

In this paper, we have developed a series of monolithic multi-element germanium detectors, based on sensor arrays produced by the Forschungzentrum Julich, and on Application-specific integrated circuits (ASICs) developed at Brookhaven. Devices have been made with element counts ranging from 64 to 384. These detectors are being used at NSLS-II and APS for a range of diffraction experiments, both monochromatic and energy-dispersive. Compact and powerful readout systems have been developed, based on the new generation of FPGA system-on-chip devices, which provide closely coupled multi-core processors embedded in large gate arrays. Finally, we will discuss the technical details of the systems,more » and present some of the results from them.« less

Multi-element germanium detectors for synchrotron applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rumaiz, A. K.; Kuczewski, A. J.; Mead, J.

In this paper, we have developed a series of monolithic multi-element germanium detectors, based on sensor arrays produced by the Forschungzentrum Julich, and on Application-specific integrated circuits (ASICs) developed at Brookhaven. Devices have been made with element counts ranging from 64 to 384. These detectors are being used at NSLS-II and APS for a range of diffraction experiments, both monochromatic and energy-dispersive. Compact and powerful readout systems have been developed, based on the new generation of FPGA system-on-chip devices, which provide closely coupled multi-core processors embedded in large gate arrays. Finally, we will discuss the technical details of the systems,more » and present some of the results from them.« less

TIGRESS highly-segmented high-purity germanium clover detector

NASA Astrophysics Data System (ADS)

Scraggs, H. C.; Pearson, C. J.; Hackman, G.; Smith, M. B.; Austin, R. A. E.; Ball, G. C.; Boston, A. J.; Bricault, P.; Chakrawarthy, R. S.; Churchman, R.; Cowan, N.; Cronkhite, G.; Cunningham, E. S.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Leslie, J. R.; Martin, J.-P.; Morris, D.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Svensson, C. E.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.; Zimmerman, L.

2005-05-01

The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS) will consist of twelve units of four high-purity germanium (HPGe) crystals in a common cryostat. The outer contacts of each crystal will be divided into four quadrants and two lateral segments for a total of eight outer contacts. The performance of a prototype HPGe four-crystal unit has been investigated. Integrated noise spectra for all contacts were measured. Energy resolutions, relative efficiencies for both individual crystals and for the entire unit, and peak-to-total ratios were measured with point-like sources. Position-dependent performance was measured by moving a collimated source across the face of the detector.

Infrared absorption study of neutron-transmutation-doped germanium

NASA Technical Reports Server (NTRS)

Park, I. S.; Haller, E. E.

1988-01-01

Using high-resolution far-infrared Fourier transform absorption spectroscopy and Hall effect measurements, the evolution of the shallow acceptor and donor impurity levels in germanium during and after the neutron transmutation doping process was studied. The results show unambiguously that the gallium acceptor level concentration equals the concentration of transmutated Ge-70 atoms during the whole process indicating that neither recoil during transmutation nor gallium-defect complex formation play significant roles. The arsenic donor levels appear at full concentration only after annealing for 1 h at 450 C. It is shown that this is due to donor-radiation-defect complex formation. Again, recoil does not play a significant role.

The Contrast in Outgassing of Germanium Between Shergottites and Nakhlites

NASA Technical Reports Server (NTRS)

Yang, S.; Humayun, M.; Righter, K.; Peslier, A. H.

2018-01-01

Final Paper and not the abstract is attached. Introduction: Germanium is generally thought to follow Si in its geochemical behavior, but little data has existed to rigorously understand the behavior of Ge in the Martian mantle. Germanium is known to be more siderophile than Si, and its partitioning into the martian core has been studied by. Typical abundances in igneous martian meteorites range from 0.5-3 ppm, a larger range than what is observed in terrestrial basalts (1.5 +/- 0.1 ppm). In situ measurements by the MER and MSL rovers have revealed a surprisingly large range in Ge abundances in surface rocks (30-650 ppm), but many igneous rocks and soils are shown to have greater than 30 ppm Ge (the detection limit of the APXS). Recently, reported that shergottite minerals showed a depletion of Ge with increasing fractionation, while nakhlites and chassignites exhibited Ge behavior compatible with closed system igneous differentiation. They interpreted their observations as tentatively indicating volcanic outgassing of Ge from shergottites (but not from nakhlite-chassignites) with recondensation of the Ge vapor into soils and breccias. Recent experimental studies show that Ge is significantly volatile from magmas. In this study, we followed up on those results by analyzing minerals in five nakhlites and five shergottites by laser ablation ICP-MS (LA-ICP-MS). See Attached

Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

NASA Astrophysics Data System (ADS)

Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

2014-05-01

Availability of elements in soil to plant is generally dependent on the solubility and mobility of elements in soil solution which is controlled by soil, elemental properties and plant-soil interactions. Low molecular organic acids or other root exudates may increase mobility and availability of certain elements for plants as an effect of lowering pH in the rhizosphere and complexation. However, these processes take place in a larger volume in soil, therefore to understand their nature, it is also important to know in which layers of the soil what factors modify these processes. In this work the influence of citric acid and root exudates of white lupin (Lupinus albus L.) on bioavailable concentrations of germanium, lanthan, neodymium, gadolinium and erbium in soil solution and uptake in root and shoot of rape (Brassica napus L.), comfrey (Symphytum officinale L.), common millet (Panicum milliaceum L.) and oat (Avena sativa L.) was investigated. Two different pot experiments were conducted: (1) the mentioned plant species were treated with nutrient solutions containing various amount of citric acid; (2) white lupin was cultivated in mixed culture (0 % lupin, 33 % lupin) with oat (Avena sativa L.) and soil solution was obtained by plastic suction cups placed at various depths. As a result, addition of citric acid significantly increased germanium concentrations in plant tissue of comfrey and rape and increased translocation of germanium, lanthan, neodymium, gadolinium and erbium from root to shoot. The cultivation of white lupin in mixed culture with oat led to significantly higher concentrations of germanium and increasing concentrations of lanthan, neodymium, gadolinium and erbium in soil solution and aboveground plant tissue. In these pots concentrations of citric acid in soil solution were significantly higher than in the control. The results show, that low molecular organic acids exuded by plant roots are of great importance for the mobilization of germanium

EVALUATION OF THE IMPACT OF THE DEFENSE WASTE PROCESSING FACILITY (DWPF) LABORATORY GERMANIUM OXIDE USE ON RECYCLE TRANSFERS TO THE H-TANK FARM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Laurinat, J.

2011-08-15

When processing High Level Waste (HLW) glass, the Defense Waste Processing Facility (DWPF) cannot wait until the melt or waste glass has been made to assess its acceptability, since by then no further changes to the glass composition and acceptability are possible. Therefore, the acceptability decision is made on the upstream feed stream, rather than on the downstream melt or glass product. This strategy is known as 'feed forward statistical process control.' The DWPF depends on chemical analysis of the feed streams from the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mix Evaporator (SME) where the frit plusmore » adjusted sludge from the SRAT are mixed. The SME is the last vessel in which any chemical adjustments or frit additions can be made. Once the analyses of the SME product are deemed acceptable, the SME product is transferred to the Melter Feed Tank (MFT) and onto the melter. The SRAT and SME analyses have been analyzed by the DWPF laboratory using a 'Cold Chemical' method but this dissolution did not adequately dissolve all the elemental components. A new dissolution method which fuses the SRAT or SME product with cesium nitrate (CsNO{sub 3}), germanium (IV) oxide (GeO{sub 2}) and cesium carbonate (Cs{sub 2}CO{sub 3}) into a cesium germanate glass at 1050 C in platinum crucibles has been developed. Once the germanium glass is formed in that fusion, it is readily dissolved by concentrated nitric acid (about 1M) to solubilize all the elements in the SRAT and/or SME product for elemental analysis. When the chemical analyses are completed the acidic cesium-germanate solution is transferred from the DWPF analytic laboratory to the Recycle Collection Tank (RCT) where the pH is increased to {approx}12 M to be released back to the tank farm and the 2H evaporator. Therefore, about 2.5 kg/yr of GeO{sub 2}/year will be diluted into 1.4 million gallons of recycle. This 2.5 kg/yr of GeO{sub 2} may increase to 4 kg/yr when improvements are implemented to

Time-resolved measurements of the angular distribution of lasing at 23.6 nm in Ne-like germanium

NASA Astrophysics Data System (ADS)

Kodama, R.; Neely, D.; Dwivedi, L.; Key, M. H.; Krishnan, J.; Lewis, C. L. S.; O'Neill, D.; Norreys, P.; Pert, G. J.; Ramsden, S. A.; Tallents, G. J.; Uhomoibhi, J.; Zhang, J.

1992-06-01

The time dependence of the angular distribution of soft X-ray lasing at 23.6 nm in Ne-like germanium has been measured using a streak camera. Slabs of germanium have been irradiated over ≈ 22 mm length × 100 μm width with three line focussed beams of the SERC Rutherford Appleton Laboratory VULCAN laser at 1.06 μm wavelength. The laser beam sweeps in time towards the target surface plane and the divergence broadens with time. The change of the peak intensity pointing and the broadening of the profile with time are consistent with expectations of the time dependence of refraction and divergence due to density gradients in the plasma.

Effect of germanium concentrations on tunnelling current calculation of Si/Si1-xGex/Si heterojunction bipolar transistor

NASA Astrophysics Data System (ADS)

Hasanah, L.; Suhendi, E.; Khairrurijal

2018-05-01

Tunelling current calculation on Si/Si1-xGex/Si heterojunction bipolar transistor was carried out by including the coupling between transversal and longitudinal components of electron motion. The calculation results indicated that the coupling between kinetic energy in parallel and perpendicular to S1-xGex barrier surface affected tunneling current significantly when electron velocity was faster than 1x105 m/s. This analytical tunneling current model was then used to study how the germanium concentration in base to Si/Si1-xGex/Si heterojunction bipolar transistor influenced the tunneling current. It is obtained that tunneling current increased as the germanium concentration given in base decreased.

Measurement of the quantum conductance of germanium by an electrochemical scanning tunneling microscope break junction based on a jump-to-contact mechanism.

PubMed

Xie, Xufen; Yan, Jiawei; Liang, Jinghong; Li, Jijun; Zhang, Meng; Mao, Bingwei

2013-10-01

We present quantum conductance measurements of germanium by means of an electrochemical scanning tunneling microscope (STM) break junction based on a jump-to-contact mechanism. Germanium nanowires between a platinum/iridium tip and different substrates were constructed to measure the quantum conductance. By applying appropriate potentials to the substrate and the tip, the process of heterogeneous contact and homogeneous breakage was realized. Typical conductance traces exhibit steps at 0.025 and 0.05 G0. The conductance histogram indicates that the conductance of germanium nanowires is located between 0.02 and 0.15 G0 in the low-conductance region and is free from the influence of substrate materials. However, the distribution of conductance plateaus is too discrete to display distinct peaks in the conductance histogram of the high-conductance region. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Silicon and germanium nanoparticles with tailored surface chemistry as novel inorganic fiber brightening agents.

PubMed

Deb-Choudhury, Santanu; Prabakar, Sujay; Krsinic, Gail; Dyer, Jolon M; Tilley, Richard D

2013-07-31

Low-molecular-weight organic molecules, such as coumarins and stilbenes, are used commercially as fluorescent whitening agents (FWAs) to mask photoyellowing and to brighten colors in fabrics. FWAs achieve this by radiating extra blue light, thus changing the hue and also adding to the brightness. However, organic FWAs can rapidly photodegrade in the presence of ultraviolet (UV) radiation, exacerbating the yellowing process through a reaction involving singlet oxygen species. Inorganic nanoparticles, on the other hand, can provide a similar brightening effect with the added advantage of photostability. We report a targeted approach in designing new inorganic silicon- and germanium-based nanoparticles, functionalized with hydrophilic (amine) surface terminations as novel inorganic FWAs. When applied on wool, by incorporation in a sol-gel Si matrix, the inorganic FWAs improved brightness properties, demonstrated enhanced photostability toward UV radiation, especially the germanium nanoparticles, and also generated considerably lower levels of reactive oxygen species compared to a commercial stilbene-based organic FWA, Uvitex NFW.

SU-C-201-02: Quantitative Small-Animal SPECT Without Scatter Correction Using High-Purity Germanium Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gearhart, A; Peterson, T; Johnson, L

2015-06-15

Purpose: To evaluate the impact of the exceptional energy resolution of germanium detectors for preclinical SPECT in comparison to conventional detectors. Methods: A cylindrical water phantom was created in GATE with a spherical Tc-99m source in the center. Sixty-four projections over 360 degrees using a pinhole collimator were simulated. The same phantom was simulated using air instead of water to establish the true reconstructed voxel intensity without attenuation. Attenuation correction based on the Chang method was performed on MLEM reconstructed images from the water phantom to determine a quantitative measure of the effectiveness of the attenuation correction. Similarly, a NEMAmore » phantom was simulated, and the effectiveness of the attenuation correction was evaluated. Both simulations were carried out using both NaI detectors with an energy resolution of 10% FWHM and Ge detectors with an energy resolution of 1%. Results: Analysis shows that attenuation correction without scatter correction using germanium detectors can reconstruct a small spherical source to within 3.5%. Scatter analysis showed that for standard sized objects in a preclinical scanner, a NaI detector has a scatter-to-primary ratio between 7% and 12.5% compared to between 0.8% and 1.5% for a Ge detector. Preliminary results from line profiles through the NEMA phantom suggest that applying attenuation correction without scatter correction provides acceptable results for the Ge detectors but overestimates the phantom activity using NaI detectors. Due to the decreased scatter, we believe that the spillover ratio for the air and water cylinders in the NEMA phantom will be lower using germanium detectors compared to NaI detectors. Conclusion: This work indicates that the superior energy resolution of germanium detectors allows for less scattered photons to be included within the energy window compared to traditional SPECT detectors. This may allow for quantitative SPECT without implementing

Spontaneous time reversal symmetry breaking in atomically confined two-dimensional impurity bands in silicon and germanium

NASA Astrophysics Data System (ADS)

Ghosh, Arindam

Three-dimensional bulk-doped semiconductors, in particular phosphorus (P)-doped silicon (Si) and germanium (Ge), are among the best studied systems for many fundamental concepts in solid state physics, ranging from the Anderson metal-insulator transition to the many-body Coulomb interaction effects on quantum transport. Recent advances in material engineering have led to vertically confined doping of phosphorus (P) atoms inside bulk crystalline silicon and germanium, where the electron transport occurs through one or very few atomic layers, constituting a new and unique platform to investigate many of these phenomena at reduced dimensions. In this talk I shall present results of extensive quantum transport experiments in delta-doped silicon and germanium epilayers, over a wide range of doping density that allow independent tuning of the on-site Coulomb interaction and hopping energy scales. We find that low-frequency flicker noise, or the 1 / f noise, in the electrical conductance of these systems is exceptionally low, and in fact among the lowest when compared with other low-dimensional materials. This is attributed to the physical separation of the conduction electrons, embedded inside the crystalline semiconductor matrix, from the charged fluctuators at the surface. Most importantly, we find a remarkable suppression of weak localization effects, including the quantum correction to conductivity and universal conductance fluctuations, with decreasing doping density or, equivalently, increasing effective on-site Coulomb interaction. In-plane magneto-transport measurements indicate the presence of intrinsic local spin fluctuations at low doping although no signatures of long range magnetic order could be identified. We argue that these results indicate a spontaneous breakdown of time reversal symmetry, which is one of the most fundamental and robust symmetries of nonmagnetic quantum systems. While the microscopic origin of this spontaneous time reversal symmetry

A self-aligned dry etching method for mechanical strain enhancement of germanium and its uniformity improvement for photonic applications

NASA Astrophysics Data System (ADS)

Lin, Yiding; Ma, Danhao; Lee, Kwang Hong; Michel, Jurgen; Tan, Chuan Seng

2018-02-01

A self-aligned dry etching method was proposed and verified theoretically to enhance the magnitude and simultaneously improve the uniformity of the tensile strain in a germanium (Ge) wave-guide (WG), with the help of tensile-stressed SiN stressor at the WG sidewalls. The SiN-strained germanium-on-insulator (GOI) WG was also experimentally demonstrated. Significant tensile strain was observed in the Ge material via micro-Raman measurements. This method could potentially facilitate a Ge photodetector with its optical detection range extended further towards longer wavelength and to be comparable with that of state-of-the-art InGaAs detectors.

Strategies for single-point diamond machining a large format germanium blazed immersion grating

NASA Astrophysics Data System (ADS)

Montesanti, R. C.; Little, S. L.; Kuzmenko, P. J.; Bixler, J. V.; Jackson, J. L.; Lown, J. G.; Priest, R. E.; Yoxall, B. E.

2016-07-01

A large format germanium immersion grating was flycut with a single-point diamond tool on the Precision Engineering Research Lathe (PERL) at the Lawrence Livermore National Laboratory (LLNL) in November - December 2015. The grating, referred to as 002u, has an area of 59 mm x 67 mm (along-groove and cross-groove directions), line pitch of 88 line/mm, and blaze angle of 32 degree. Based on total groove length, the 002u grating is five times larger than the previous largest grating (ZnSe) cut on PERL, and forty-five times larger than the previous largest germanium grating cut on PERL. The key risks associated with cutting the 002u grating were tool wear and keeping the PERL machine running uninterrupted in a stable machining environment. This paper presents the strategies employed to mitigate these risks, introduces pre-machining of the as-etched grating substrate to produce a smooth, flat, damage-free surface into which the grooves are cut, and reports on trade-offs that drove decisions and experimental results.

Optical Activation of Germanium Plasmonic Antennas in the Mid-Infrared

NASA Astrophysics Data System (ADS)

Fischer, Marco P.; Schmidt, Christian; Sakat, Emilie; Stock, Johannes; Samarelli, Antonio; Frigerio, Jacopo; Ortolani, Michele; Paul, Douglas J.; Isella, Giovanni; Leitenstorfer, Alfred; Biagioni, Paolo; Brida, Daniele

2016-07-01

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.

Optical Activation of Germanium Plasmonic Antennas in the Mid-Infrared.

PubMed

Fischer, Marco P; Schmidt, Christian; Sakat, Emilie; Stock, Johannes; Samarelli, Antonio; Frigerio, Jacopo; Ortolani, Michele; Paul, Douglas J; Isella, Giovanni; Leitenstorfer, Alfred; Biagioni, Paolo; Brida, Daniele

2016-07-22

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.

Fabrication of SrTiO3 nanotubes via an isomorphic conversion strategy

NASA Astrophysics Data System (ADS)

Yang, Dong; Zou, Xiaoyan; Tong, Zhenwei; Nan, Yanhu; Ding, Fei; Jiang, Zhongyi

2018-02-01

One-dimensional nanotubes have attracted enormous attention due to their specific structure and excellent performance since the carbon nanotube was prepared. In this study, the open-ended SrTiO3 nanotubes (STNTs) have been fabricated for the first time via an isomorphic conversion strategy using the protonated titanate nanotubes (HTNTs) as the precursor and template under the hydrothermal treatment. The as-prepared STNTs consist of uniform and continuous multilayers, having inner and outer diameters about 8.0 and 13 nm. The STNT formation involves the exchange of Sr2+ ions with H+ ions in HTNTs and then in situ growth of cubic SrTiO3 crystals by the templating of HTNT frameworks. It is found that the diffusion process of Sr2+ ions plays a critical role in controlling the nanotube morphology of SrTiO3 crystals. In addition, the SrTiO3 nanotubes exhibit high photocatalytic activity for the Cr(VI) reduction, which can reduce nearly 100% Cr(VI) within 6 h under simulated sunlight irradiation. The current strategy may be broadly applicable for fabricating the nanotubes from raw materials without 2D layered nanostructure. [Figure not available: see fulltext.

Quantum ballistic transport in strained epitaxial germanium

NASA Astrophysics Data System (ADS)

Gul, Y.; Holmes, S. N.; Newton, P. J.; Ellis, D. J. P.; Morrison, C.; Pepper, M.; Barnes, C. H. W.; Myronov, M.

2017-12-01

Large scale fabrication using Complementary Metal Oxide Semiconductor compatible technology of semiconductor nanostructures that operate on the principles of quantum transport is an exciting possibility now due to the recent development of ultra-high mobility hole gases in epitaxial germanium grown on standard silicon substrates. We present here a ballistic transport study of patterned surface gates on strained Ge quantum wells with SiGe barriers, which confirms the quantum characteristics of the Ge heavy hole valence band structure in 1-dimension. Quantised conductance at multiples of 2e2/h is a universal feature of hole transport in Ge up to 10 × (2e2/h). The behaviour of ballistic plateaus with finite source-drain bias and applied magnetic field is elucidated. In addition, a reordering of the ground state is observed.

Multielemental analyses of isomorphous Indian garnet gemstones by XRD and external pixe techniques.

PubMed

Venkateswarulu, P; Srinivasa Rao, K; Kasipathi, C; Ramakrishna, Y

2012-12-01

Garnet gemstones were collected from parts of Eastern Ghats geological formations of Andhra Pradesh, India and their gemological studies were carried out. Their study of chemistry is not possible as they represent mixtures of isomorphism nature, and none of the individual specimens indicate independent chemistry. Hence, non-destructive instrumental methodology of external PIXE technique was employed to understand their chemistry and identity. A 3 MeV proton beam was employed to excite the samples. In the present study geochemical characteristics of garnet gemstones were studied by proton induced X-ray emission. Almandine variety of garnet is found to be abundant in the present study by means of their chemical contents. The crystal structure and the lattice parameters were estimated using X-Ray Diffraction studies. The trace and minor elements are estimated using PIXE technique and major compositional elements are confirmed by XRD studies. The technique is found very useful in characterizing the garnet gemstones. The present work, thus establishes usefulness and versatility of the PIXE technique with external beam for research in Geo-scientific methodology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Atomic Layer Deposition of Metastable β-Fe 2 O 3 via Isomorphic Epitaxy for Photoassisted Water Oxidation

DOE PAGES

Emery, Jonathan D.; Schlepütz, Christian M.; Guo, Peijun; ...

2014-12-09

Here, we report the growth and photoelectrochemical (PEC) characterization of the uncommon bibyite phase of iron(III) oxide (β-Fe 2O 3) epitaxially stabilized via atomic layer deposition on an conductive, transparent, and isomorphic template (Sn-doped In 2O 3). Furthermore, as a photoanode, unoptimized β-Fe 2O 3 ultrathin films perform similarly to their ubiquitous α-phase (hematite) counterpart, but reveal a more ideal bandgap (1.8 eV), a ~0.1 V improved photocurrent onset potential, and longer wavelength (>600 nm) spectral response. Finally, stable operation under basic water oxidation justifies further exploration of this atypical phase and motivates the investigation of other unexplored metastable phasesmore » as new PEC materials.« less

21 CFR 100.155 - Salt and iodized salt.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the...

On the introduction of a measurement standard for high-purity germanium crystals to be used in radiation detectors

NASA Astrophysics Data System (ADS)

Darken, L.

1994-02-01

The IEEE and ANSI have recently approved "Standard Test Procedures for High-Purity Germanium Crystals for Radiation Detectors" proposed by the IEEE/NPSS/Nuclear Instruments and Detectors Committee. The standard addresses three aspects of the characterisation of high-purity germanium: (i) the determination by the van der Pauw method of the net carrier concentration and type; (ii) the measurement by capacitance transient techniques of the concentration of trapping levels; (iii) the description of the crystallographic properties revealed by preferential etching. In addition to describing the contents of this standard, the purpose of this work is also to place the issues faced in the context of professional consensus: points of agreement, points of disagreement, and subjects poorly understood.

Atomic Scale Structure of (001) Hydrogen-Induced Platelets in Germanium

NASA Astrophysics Data System (ADS)

David, Marie-Laure; Pizzagalli, Laurent; Pailloux, Fréderic; Barbot, Jean François

2009-04-01

An accurate characterization of the structure of hydrogen-induced platelets is a prerequisite for investigating both hydrogen aggregation and formation of larger defects. On the basis of quantitative high resolution transmission electron microscopy experiments combined with extensive first principles calculations, we present a model for the atomic structure of (001) hydrogen-induced platelets in germanium. It involves broken Ge-Ge bonds in the [001] direction that are dihydride passivated, vacancies, and trapped H2 molecules, showing that the species involved in platelet formation depend on the habit plane. This model explains all previous experimental observations.

Three holes bound to a double acceptor - Be(+) in germanium

NASA Technical Reports Server (NTRS)

Haller, E. E.; Mcmurray, R. E., Jr.; Falicov, L. M.; Haegel, N. M.; Hansen, W. L.

1983-01-01

A double acceptor binding three holes has been observed for the first time with photoconductive far-infrared spectroscopy in beryllium-doped germanium single crystals. This new center, Be(+), has a hole binding energy of about 5 meV and is only present when free holes are generated by ionization of either neutral shallow acceptors or neutral Be double acceptors. The Be(+) center thermally ionizes above 4 K. It disappears at a uniaxial stress higher than about a billion dyn/sq cm parallel to (111) as a result of the lifting of the valence-band degeneracy.

Diclofenac salts. III. Alkaline and earth alkaline salts.

PubMed

Fini, Adamo; Fazio, Giuseppe; Rosetti, Francesca; Angeles Holgado, M; Iruín, Ana; Alvarez-Fuentes, Josefa

2005-11-01

Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.

Refractive Index of Silicon and Germanium and Its Wavelength and Temperature Derivatives.

DTIC Science & Technology

1979-03-01

of a misnomer and, although Clemens Winkler is cred- ited with the discovery of the element in 1886, germanium has become an element of interest in...rather small in covalent semiconductors like Si and Ge, it increases, however, with increasing polarity. Both the radio -frequency mea- surement and...temperature region 250-480 K, but nonlinearity progressively predominates at lower temperatures, as seen from figure 7. Lukes and Schmidt [18] studied

Lithium effects on the mechanical and electronic properties of germanium nanowires

NASA Astrophysics Data System (ADS)

González-Macías, A.; Salazar, F.; Miranda, A.; Trejo-Baños, A.; Pérez, L. A.; Carvajal, E.; Cruz-Irisson, M.

2018-04-01

Semiconductor nanowire arrays promise rapid development of a new generation of lithium (Li) batteries because they can store more Li atoms than conventional crystals due to their large surface areas. During the charge-discharge process, the electrodes experience internal stresses that fatigue the material and limit the useful life of the battery. The theoretical study of electronic and mechanical properties of lithiated nanowire arrays allows the designing of electrode materials that could improve battery performance. In this work, we present a density functional theory study of the electronic band structure, formation energy, binding energy, and Young’s modulus (Y) of hydrogen passivated germanium nanowires (H-GeNWs) grown along the [111] and [001] crystallographic directions with surface and interstitial Li atoms. The results show that the germanium nanowires (GeNWs) with surface Li atoms maintain their semiconducting behavior but their energy gap size decreases when the Li concentration grows. In contrast, the GeNWs can have semiconductor or metallic behavior depending on the concentration of the interstitial Li atoms. On the other hand, Y is an indicator of the structural changes that GeNWs suffer due to the concentration of Li atoms. For surface Li atoms, Y stays almost constant, whereas for interstitial Li atoms, the Y values indicate important structural changes in the GeNWs.

Effect of germanium dioxide on growth of Spirulina platensis

NASA Astrophysics Data System (ADS)

Cao, Ji-Xiang

1996-12-01

This study on the effect of different concentrations of germanium dioxide (GeO2) on the specific growth rate (SGR), pigment contents, protein content and amino acid composition of Spirulina platensis showed that Ge was not the essential element of this alga; that GeO2 could speed up growth and raise protein content of S. platensis, and could possibly influence the photosynthesis system. The concentration range of GeO2 beneficial to growth of S. platensis is from 5 100mg/l. GeO2 is proposed to be utilized to remove contamination by Chlorella spp. usually occurring in the cultivation of Spirulina.

Neutron Transmutation Doped (NTD) germanium thermistors for sub-mm bolometer applications

NASA Technical Reports Server (NTRS)

Haller, E. E.; Itoh, K. M.; Beeman, J. W.

1996-01-01

Recent advances in the development of neutron transmutation doped (NTD) semiconductor thermistors fabricated from natural and controlled isotopic composition germanium are reported. The near ideal doping uniformity that can be achieved with the NTD process, the device simplicity of NTD Ge thermistors and the high performance of cooled junction field effect transistor preamplifiers led to the widespread acceptance of these thermal sensors in ground-based, airborne and spaceborne radio telescopes. These features made possible the development of efficient bolometer arrays.

Effect of Isomorphous Substitution on the Thermal Decomposition Mechanism of Hydrotalcites

PubMed Central

Crosby, Sergio; Tran, Doanh; Cocke, David; Duraia, El-Shazly M.; Beall, Gary W.

2014-01-01

Hydrotalcites have many important applications in catalysis, wastewater treatment, gene delivery and polymer stabilization, all depending on preparation history and treatment scenarios. In catalysis and polymer stabilization, thermal decomposition is of great importance. Hydrotalcites form easily with atmospheric carbon dioxide and often interfere with the study of other anion containing systems, particularly if formed at room temperature. The dehydroxylation and decomposition of carbonate occurs simultaneously, making it difficult to distinguish the dehydroxylation mechanisms directly. To date, the majority of work on understanding the decomposition mechanism has utilized hydrotalcite precipitated at room temperature. In this study, evolved gas analysis combined with thermal analysis has been used to show that CO2 contamination is problematic in materials being formed at RT that are poorly crystalline. This has led to some dispute as to the nature of the dehydroxylation mechanism. In this paper, data for the thermal decomposition of the chloride form of hydrotalcite are reported. In addition, carbonate-free hydrotalcites have been synthesized with different charge densities and at different growth temperatures. This combination of parameters has allowed a better understanding of the mechanism of dehydroxylation and the role that isomorphous substitution plays in these mechanisms to be delineated. In addition, the effect of anion type on thermal stability is also reported. A stepwise dehydroxylation model is proposed that is mediated by the level of aluminum substitution. PMID:28788231

A model for the effects of germanium on silica biomineralization in choanoflagellates

PubMed Central

Chappell, Helen; Ratcliffe, Sarah; Goldstein, Raymond E.

2016-01-01

Silica biomineralization is a widespread phenomenon of major biotechnological interest. Modifying biosilica with substances like germanium (Ge) can confer useful new properties, although exposure to high levels of Ge disrupts normal biosilicification. No clear mechanism explains why this disruption occurs. Here, we study the effect of Ge on loricate choanoflagellates, a group of protists that construct a species-specific extracellular lorica from multiple siliceous costal strips. High Ge exposures were toxic, whereas lower Ge exposures produced cells with incomplete or absent loricae. These effects can be ameliorated by restoring the germanium : silicon ratio, as observed in other biosilicifying organisms. We developed simulations of how Ge interacts with polymerizing silica. In our models, Ge is readily incorporated at the ends of silica forming from silicic acid condensation, but this prevents further silica polymerization. Our ‘Ge-capping’ model is supported by observations from loricate choanoflagellates. Ge exposure terminates costal strip synthesis and lorica formation, resulting in disruption to cytokinesis and fatal build-up of silicic acid. Applying the Ge-capping model to other siliceous organisms explains the general toxicity of Ge and identifies potential protective responses in metalloid uptake and sensing. This can improve the design of new silica biomaterials, and further our understanding of silicon metabolism. PMID:27655668

Controlled synthesis of germanium nanoparticles by nonthermal plasmas

NASA Astrophysics Data System (ADS)

Ahadi, Amir Mohammad; Hunter, Katharine I.; Kramer, Nicolaas J.; Strunskus, Thomas; Kersten, Holger; Faupel, Franz; Kortshagen, Uwe R.

2016-02-01

The size, composition, and crystallinity of plasma produced nanoparticles are crucial factors for their physical and chemical properties. Here, we investigate the role of the process gas composition, particularly the hydrogen (H2) flow rate, on germanium (Ge) nanoparticles synthesized from a chlorinated precursor by nonthermal plasma. We demonstrate that the gas composition can significantly change the nanoparticle size and also adjust the surface chemistry by altering the dominant reaction mechanisms. A red shift of the Ge-Clx infrared absorptions with increasing H2 flow indicates a weakening of the Ge-Clx bonds at high H2 content. Furthermore, by changing the gas composition, the nanoparticles microstructure can be controlled from mostly amorphous at high hydrogen flow to diamond cubic crystalline at low hydrogen flow.

Molybdenum blue reaction and determination of phosphorus in waters containing arsenic, silicon, and germanium

USGS Publications Warehouse

Levine, H.; Rowe, J.J.; Grimaldi, F.S.

1955-01-01

Microgram amounts of phosphate are usually determined by the molybdenum blue reaction, but this reaction is not specific for phosphorus. The research established the range of conditions under which phosphate, arsenate, silicate, and germanate give the molybdenum blue reaction for differentiating these elements, and developed a method for the determination of phosphate in waters containing up to 10 p.p.m. of the oxides of germanium, arsenic(V), and silicon. With stannous chloride or 1-amino-2-naphthol-4-sulfonic acid as the reducing agent no conditions were found for distinguishing silicate from germanate and phosphate from arsenate. In the recommended procedure the phosphate is concentrated by coprecipitation on aluminum hydroxide, and coprecipitated arsenic, germanium, and silicon are volatilized by a mixture of hydrofluoric, hydrochloric, and hydrobromic acids prior to the determination of phosphate. The authors are able to report that the total phosphorus content of several samples of sea water from the Gulf of Mexico ranged from 0.018 to 0.059 mg. of phosphorus pentoxide per liter of water.

Consumer knowledge and attitudes to salt intake and labelled salt information.

PubMed

Grimes, Carley A; Riddell, Lynn J; Nowson, Caryl A

2009-10-01

The objective of this study was to investigate consumers' knowledge of health risks of high salt intake and frequency of use and understanding of labelled salt information. We conducted a cross-sectional survey in shopping centres within Metropolitan Melbourne. A sample of 493 subjects was recruited. The questionnaire assessed salt related shopping behaviours, attitudes to salt intake and health and their ability to interpret labelled sodium information. Four hundred and seventy four valid surveys were collected (65% female, 64% being the main shopper). Most participants knew of the relationship between salt intake and high blood pressure (88%). Sixty five percent of participants were unable to correctly identify the relationship between salt and sodium. Sixty nine percent reported reading the salt content of food products when shopping. Salt label usage was significantly related to shoppers concern about the amount of salt in their diet and the belief that their health could improve by lowering salt intake. Approximately half of the sample was unable to accurately use labelled sodium information to pick low salt options. Raising consumer awareness of the health risks associated with high salt consumption may increase salt label usage and purchases of low salt foods. However, for food labels to be effective in helping consumers select low salt foods a more 'user friendly' labelling format is needed.

Investigation of salt loss from the Bonneville Salt Flats, northwestern Utah

USGS Publications Warehouse

Mason, James L.; Kipp, Kenneth L.

1997-01-01

The Bonneville Salt Flats study area is located in the western part of the Great Salt Lake Desert in northwestern Utah, about 110 miles west of Salt Lake City. The salt crust covers about 50 square miles, but the extent varies yearly as a result of salt being dissolved by the formation and movement of surface ponds during the winter and redeposited with the evaporation of these ponds during the summer.A decrease in thickness and extent of the salt crust on the Bonneville Salt Flats has been documented during 1960-88 (S. Brooks, Bureau of Land Management, written commun., 1989). Maximum salt-crust thickness was 7 feet in 1960 and 5.5 feet in 1988. No definitive data are available to identify and quantify the processes that cause salt loss. More than 55 million tons of salt are estimated to have been lost from the salt crust during the 28-year period. The Bureau of Land Management needs to know the causes of salt loss to make appropriate management decisions.

The Constellation-X Focal Plane Microcalorimeter Array: An NTD-Germanium Solution

NASA Technical Reports Server (NTRS)

Beeman, J.; Silver, E.; Bandler, S.; Schnopper, H.; Murray, S.; Madden, N.; Landis, D.; Haller, E. E.; Barbera, M.

2001-01-01

The hallmarks of Neutron Transmutation Doped (NTD) germanium cryogenic thermistors include high reliability, reproducibility, and long term stability of bulk carrier transport properties. Using micro-machined NTD Ge thermistors with integral 'flying' leads, we can now fabricate two-dimensional arrays that are built up from a series of stacked linear arrays. We believe that this modular approach of building, assembling, and perhaps replacing individual modules of detectors is essential to the successful fabrication and testing of large multi-element instruments. Details of construction are presented.

Effect on magnetic properties of germanium encapsulated C60 fullerene

NASA Astrophysics Data System (ADS)

Umran, Nibras Mossa; Kumar, Ranjan

2013-02-01

Structural and electronic properties of Gen(n = 1-4) doped C60 fullerene are investigated with ab initio density functional theory calculations by using an efficient computer code, known as SIESTA. The pseudopotentials are constructed using a Trouiller-Martins scheme, to describe the interaction of valence electrons with the atomic cores. In endohedral doped embedding of more germanium atoms complexes we have seen that complexes are stable and thereafter cage break down. We have also investigated that binding energy, electronic affinity increases and magnetic moment oscillating behavior as the number of semiconductor atoms in C60 fullerene goes on increasing.

Fabrication and characterization of a germanium nanowire light emitting diode

NASA Astrophysics Data System (ADS)

Greil, Johannes; Bertagnolli, Emmerich; Salem, Bassem; Baron, Thierry; Gentile, Pascal; Lugstein, Alois

2017-12-01

In this letter, we demonstrate the feasibility of a germanium nanowire light emitting diode as a reasonable approach for downscaling of CMOS compatible light sources. We show room-temperature direct bandgap electroluminescence from axial p-n junction nanowire devices. The electron population in the Γ valley, necessary for direct bandgap emission, is achieved by high injection current densities. Carrier temperature is consistently found to be higher than the lattice temperature, indicating inhibited carrier cooling in small diameter wires. Strong polarization of the emission parallel to the nanowire axis is observed and attributed to dielectric contrast phenomena.

Topological Isomorphisms of Human Brain and Financial Market Networks

PubMed Central

Vértes, Petra E.; Nicol, Ruth M.; Chapman, Sandra C.; Watkins, Nicholas W.; Robertson, Duncan A.; Bullmore, Edward T.

2011-01-01

Although metaphorical and conceptual connections between the human brain and the financial markets have often been drawn, rigorous physical or mathematical underpinnings of this analogy remain largely unexplored. Here, we apply a statistical and graph theoretic approach to the study of two datasets – the time series of 90 stocks from the New York stock exchange over a 3-year period, and the fMRI-derived time series acquired from 90 brain regions over the course of a 10-min-long functional MRI scan of resting brain function in healthy volunteers. Despite the many obvious substantive differences between these two datasets, graphical analysis demonstrated striking commonalities in terms of global network topological properties. Both the human brain and the market networks were non-random, small-world, modular, hierarchical systems with fat-tailed degree distributions indicating the presence of highly connected hubs. These properties could not be trivially explained by the univariate time series statistics of stock price returns. This degree of topological isomorphism suggests that brains and markets can be regarded broadly as members of the same family of networks. The two systems, however, were not topologically identical. The financial market was more efficient and more modular – more highly optimized for information processing – than the brain networks; but also less robust to systemic disintegration as a result of hub deletion. We conclude that the conceptual connections between brains and markets are not merely metaphorical; rather these two information processing systems can be rigorously compared in the same mathematical language and turn out often to share important topological properties in common to some degree. There will be interesting scientific arbitrage opportunities in further work at the graph-theoretically mediated interface between systems neuroscience and the statistical physics of financial markets. PMID:22007161

Satellite thermal storage systems using metallic phase-change materials

NASA Astrophysics Data System (ADS)

Lauf, R. J.; Hamby, C.

Solar (thermal) dynamic power systems for satellites require a heat storage system capable of operating the engine during eclipse. A system is described in which the phase-change material (PCM) is a metal rather than the more conventional fluoride salts. Thermal storage modules consisting of germanium contained in graphite have good thermal conductivity, low parasitic mass, and are physically and chemically stable. The result is described for thermal cycle testing of graphite capsules containing germanium and several germanium- and silicon-based alloys, as well as some initial tests of the compatibility of graphite with Nb-1 percent Zr structural materials.

Where Does Road Salt Go - a Static Salt Model

NASA Astrophysics Data System (ADS)

Yu, C. W.; Liu, F.; Moriarty, V. W.

2017-12-01

Each winter, more than 15 million tons of road salt is applied in the United States for the de-icing purpose. Considerable amount of chloride in road salt flows into streams/drainage systems with the snow melt runoff and spring storms, and eventually goes into ecologically sensitive low-lying areas in the watershed, such as ponds and lakes. In many watersheds in the northern part of US, the chloride level in the water body has increased significantly in the past decades, and continues an upward trend. The environmental and ecological impact of the elevated chloride level can no longer be ignored. However although there are many studies on the biological impact of elevated chloride levels, there are few investigations on how the spatially distributed road salt application affects various parts of the watershed. In this presentation, we propose a static road salt model as a first-order metric to address spacial distribution of salt loading. Derived from the Topological Wetness Index (TWI) in many hydrological models, this static salt model provides a spatial impact as- sessment of road salt applications. To demonstrate the effectiveness of the static model, National Elevation Dataset (NED) of ten-meter resolution of Lake George watershed in New York State is used to generate the TWI, which is used to compute a spatially dis- tributed "salt-loading coefficient" of the whole watershed. Spatially varying salt applica- tion rate is then aggregated, using the salt-loading coefficients as weights, to provide salt loading assessments of streams in the watershed. Time-aggregated data from five CTD (conductivity-temperature-depth) sensors in selected streams are used for calibration. The model outputs and the sensor data demonstrate a strong linear correlation, with the R value of 0.97. The investigation shows that the static modeling approach may provide an effective method for the understanding the input and transport of road salt to within watersheds.

Buried Porous Silicon-Germanium Layers in Monocrystalline Silicon Lattices

NASA Technical Reports Server (NTRS)

Fathauer, Robert W. (Inventor); George, Thomas (Inventor); Jones, Eric W. (Inventor)

1998-01-01

Monocrystalline semiconductor lattices with a buried porous semiconductor layer having different chemical composition is discussed and monocrystalline semiconductor superlattices with a buried porous semiconductor layers having different chemical composition than that of its monocrystalline semiconductor superlattice are discussed. Lattices of alternating layers of monocrystalline silicon and porous silicon-germanium have been produced. These single crystal lattices have been fabricated by epitaxial growth of Si and Si-Ge layers followed by patterning into mesa structures. The mesa structures are strain etched resulting in porosification of the Si-Ge layers with a minor amount of porosification of the monocrystalline Si layers. Thicker Si-Ge layers produced in a similar manner emitted visible light at room temperature.

Germanium ``hexa'' detector: production and testing

NASA Astrophysics Data System (ADS)

Sarajlić, M.; Pennicard, D.; Smoljanin, S.; Hirsemann, H.; Struth, B.; Fritzsch, T.; Rothermund, M.; Zuvic, M.; Lampert, M. O.; Askar, M.; Graafsma, H.

2017-01-01

Here we present new result on the testing of a Germanium sensor for X-ray radiation. The system is made of 3 × 2 Medipix3RX chips, bump-bonded to a monolithic sensor, and is called ``hexa''. Its dimensions are 45 × 30 mm2 and the sensor thickness was 1.5 mm. The total number of the pixels is 393216 in the matrix 768 × 512 with pixel pitch 55 μ m. Medipix3RX read-out chip provides photon counting read-out with single photon sensitivity. The sensor is cooled to -126°C and noise levels together with flat field response are measured. For -200 V polarization bias, leakage current was 4.4 mA (3.2 μ A/mm2). Due to higher leakage around 2.5% of all pixels stay non-responsive. More than 99% of all pixels are bump bonded correctly. In this paper we present the experimental set-up, threshold equalization procedure, image acquisition and the technique for bump bond quality estimate.

INNER SALTS

DTIC Science & Technology

been characterized include: (1) mesomeric phosphonium salts possessing phototropic properties; (2) pentavalent phosphorus compounds; and (3) a...Products that have been characterized include: (1) mesomeric phosphonium salts possessing phototropic properties; (2) pentavalent phosphorus compounds; and (3) a mesomeric inner salt. (Author)

Innovative remotely-controlled bending device for thin silicon and germanium crystals

NASA Astrophysics Data System (ADS)

De Salvador, D.; Carturan, S.; Mazzolari, A.; Bagli, E.; Bandiera, L.; Durighello, C.; Germogli, G.; Guidi, V.; Klag, P.; Lauth, W.; Maggioni, G.; Romagnoni, M.; Sytov, A.

2018-04-01

Steering of negatively charged particle beams below 1 GeV has demonstrated to be possible with thin bent silicon and germanium crystals. A newly designed mechanical holder was used for bending crystals, since it allows a remotely-controlled adjustment of crystal bending and compensation of unwanted torsion. Bent crystals were installed and tested at the MAMI Mainz MIcrotron to achieve steering of 0.855-GeV electrons at different bending radii. We report the description and characterization of the innovative bending device developed at INFN Laboratori Nazionali di Legnaro (LNL).

Measurement of the low-energy quenching factor in germanium using an Y 88 / Be photoneutron source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholz, B. J.; Chavarria, A. E.; Collar, J. I.

2016-12-01

We employ an 88Y/Be photoneutron source to derive the quenching factor for neutron-induced nuclear recoils in germanium, probing recoil energies from a few hundred eVnr to 8.5 keV nr. A comprehensive Monte Carlo simulation of our setup is compared to experimental data employing a Lindhard model with a free electronic energy loss k and an adiabatic correction for sub-keVnr nuclear recoils. The best fit k=0.179±0.001 obtained using a Monte Carlo Markov chain (MCMC) ensemble sampler is in good agreement with previous measurements, confirming the adequacy of the Lindhard model to describe the stopping of few-keV ions in germanium crystals at a temperaturemore » of ~77 K. This value of k corresponds to a quenching factor of 13.7% to 25.3% for nuclear recoil energies between 0.3 and 8.5 keV nr, respectively.« less

Molten salt oxidation of organic hazardous waste with high salt content.

PubMed

Lin, Chengqian; Chi, Yong; Jin, Yuqi; Jiang, Xuguang; Buekens, Alfons; Zhang, Qi; Chen, Jian

2018-02-01

Organic hazardous waste often contains some salt, owing to the widespread use of alkali salts during industrial manufacturing processes. These salts cause complications during the treatment of this type of waste. Molten salt oxidation is a flameless, robust thermal process, with inherent capability of destroying the organic constituents of wastes, while retaining the inorganic ingredients in the molten salt. In the present study, molten salt oxidation is employed for treating a typical organic hazardous waste with a high content of alkali salts. The hazardous waste derives from the production of thiotriazinone. Molten salt oxidation experiments have been conducted using a lab-scale molten salt oxidation reactor, and the emissions of CO, NO, SO 2 , HCl and dioxins are studied. Impacts are investigated from the composition of the molten salts, the types of feeding tube, the temperature of molten carbonates and the air factor. Results show that the waste can be oxidised effectively in a molten salt bath. Temperature of molten carbonates plays the most important role. With the temperature rising from 600 °C to 750 °C, the oxidation efficiency increases from 91.1% to 98.3%. Compared with the temperature, air factor has but a minor effect, as well as the composition of the molten salts and the type of feeding tube. The molten carbonates retain chlorine with an efficiency higher than 99.9% and the emissions of dioxins are below 8 pg TEQ g -1 sample. The present study shows that molten salt oxidation is a promising alternative for the disposal of organic hazardous wastes containing a high salt content.

DLTS analysis of radiation-induced defects in one-MeV electron irradiated germanium and Alsub0.17Gasub0.83As solar cells

NASA Technical Reports Server (NTRS)

Li, S. B.; Choi, C. G.; Loo, R. Y.

1985-01-01

The radiation-induced deep-level defects in one-MeV electron-irradiated germanium and AlxGal-xAs solar cell materials using the deep-level transient spectroscopy (DLTS) and C-V techniques were investigated. Defect and recombination parameters such as defect density and energy levels, capture cross sections and lifetimes for both electron and hole traps were determined. The germanium and AlGaAs p/n junction cells were irradiated by one-MeV electrons. The DLTS, I-V, and C-V measurements were performed on these cells. The results are summarized as follows: (1) for the irradiated germanium samples, the dominant electron trap was due to the E sub - 0.24 eV level with density around 4x10 to the 14th power 1/cu cm, independent of electron fluence, its origin is attributed to the vacancy-donor complex defect formed during the electron irradiation; (2) in the one-MeV electron irradiated Al0.17Ga0.83 as sample, two dominant electron traps with energies of Ec-0.19 and -0.29 eV were observed, the density for both electron traps remained nearly constant, independent of electron fluence. It is shown that one-MeV electron irradiation creates very few or no new deep-level traps in both the germanium and AlxGa1-xAs cells, and are suitable for fabricating the radiation-hard high efficiency multijunction solar cells for space applications.

Alternative process for thin layer etching: Application to nitride spacer etching stopping on silicon germanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Posseme, N., E-mail: nicolas.posseme@cea.fr; Pollet, O.; Barnola, S.

2014-08-04

Silicon nitride spacer etching realization is considered today as one of the most challenging of the etch process for the new devices realization. For this step, the atomic etch precision to stop on silicon or silicon germanium with a perfect anisotropy (no foot formation) is required. The situation is that none of the current plasma technologies can meet all these requirements. To overcome these issues and meet the highly complex requirements imposed by device fabrication processes, we recently proposed an alternative etching process to the current plasma etch chemistries. This process is based on thin film modification by light ionsmore » implantation followed by a selective removal of the modified layer with respect to the non-modified material. In this Letter, we demonstrate the benefit of this alternative etch method in term of film damage control (silicon germanium recess obtained is less than 6 A), anisotropy (no foot formation), and its compatibility with other integration steps like epitaxial. The etch mechanisms of this approach are also addressed.« less

[Salt and cancer].

PubMed

Strnad, Marija

2010-05-01

Besides cardiovascular disease, a high salt intake causes other adverse health effects, i.e., gastric and some other cancers, obesity (risk factor for many cancer sites), Meniere's disease, worsening of renal disease, triggering an asthma attack, osteoporosis, exacerbation of fluid retention, renal calculi, etc. Diets containing high amounts of food preserved by salting and pickling are associated with an increased risk of cancers of the stomach, nose and throat. Because gastric cancer is still the most common cancer in some countries (especially in Japan), its prevention is one of the most important aspects of cancer control strategy. Observations among Japanese immigrants in the U.S.A. and Brazil based on the geographic differences, the trend in cancer incidence with time, and change in the incidence patterns indicate that gastric cancer is closely associated with dietary factors such as the intake of salt and salted food. The findings of many epidemiological studies suggest that high dietary salt intake is a significant risk factor for gastric cancer and this association was found to be strong in the presence of Helicobacter (H.) pylori infection with atrophic gastritis. A high-salt intake strips the lining of the stomach and may make infection with H. pylori more likely or may exacerbate the infection. Salting, pickling and smoking are traditionally popular ways of preparing food in Japan and some parts of Asia. In addition to salt intake, cigarette smoking and low consumption of fruit and vegetables increase the risk of stomach cancer. However, it is not known whether it is specifically the salt in these foods or a combination of salt and other chemicals that can cause cancer. One study identified a mutagen in nitrite-treated Japanese salted fish, and chemical structure of this mutagen suggests that it is derived from methionine and that salt and nitrite are precursors for its formation. Working under conditions of heat stress greatly increased the workers

Germanium detectors in homeland security at PNNL

DOE PAGES

Stave, S.

2015-05-01

Neutron and gamma-ray detection is used for non-proliferation and national security applications. While lower energy resolution detectors such as NaI(Tl) have their place, high purity germanium (HPGe) also has a role to play. A detection with HPGe is often a characterization due to the very high energy resolution. However, HPGe crystals remain small and expensive leaving arrays of smaller crystals as an excellent solution. PNNL has developed two similar HPGe arrays for two very different applications. One array, the Multisensor Aerial Radiation Survey (MARS) detector is a fieldable array that has been tested on trucks, boats, and helicopters. The CASCADESmore » HPGe array is an array designed to assay samples in a low background environment. The history of HPGe arrays at PNNL and the development of MARS and CASCADES will be detailed in this paper along with some of the other applications of HPGe at PNNL.« less

Tunnel current across linear homocatenated germanium chains

NASA Astrophysics Data System (ADS)

Matsuura, Yukihito

2014-01-01

The electronic transport properties of germanium oligomers catenating into linear chains (linear Ge chains) have been theoretically studied using first principle methods. The conduction mechanism of a Ge chain sandwiched between gold electrodes was analyzed based on the density of states and the eigenstates of the molecule in a two-probe environment. Like that of silicon chains (Si chains), the highest occupied molecular orbital of Ge chains contains the extended σ-conjugation of Ge 4p orbitals at energy levels close to the Fermi level; this is in contrast to the electronic properties of linear carbon chains. Furthermore, the conductance of a Ge chain is expected to decrease exponentially with molecular length L. The decay constant β, which is defined as e-βL, of a Ge chain is similar to that of a Si chain, whereas the conductance of the Ge chains is higher than that of Si chains even though the Ge-Ge bond length is longer than the Si-Si bond length.

Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing

NASA Astrophysics Data System (ADS)

Almuslem, A. S.; Hanna, A. N.; Yapici, T.; Wehbe, N.; Diallo, E. M.; Kutbee, A. T.; Bahabry, R. R.; Hussain, M. M.

2017-02-01

In the recent past, with the advent of transient electronics for mostly implantable and secured electronic applications, the whole field effect transistor structure has been dissolved in a variety of chemicals. Here, we show simple water soluble nano-scale (sub-10 nm) germanium oxide (GeO2) as the dissolvable component to remove the functional structures of metal oxide semiconductor devices and then reuse the expensive germanium substrate again for functional device fabrication. This way, in addition to transiency, we also show an environmentally friendly manufacturing process for a complementary metal oxide semiconductor (CMOS) technology. Every year, trillions of complementary metal oxide semiconductor (CMOS) electronics are manufactured and billions are disposed, which extend the harmful impact to our environment. Therefore, this is a key study to show a pragmatic approach for water soluble high performance electronics for environmentally friendly manufacturing and bioresorbable electronic applications.

Search for global-minimum geometries of medium-sized germanium clusters. II. Motif-based low-lying clusters Ge21-Ge29

NASA Astrophysics Data System (ADS)

Yoo, S.; Zeng, X. C.

2006-05-01

We performed a constrained search for the geometries of low-lying neutral germanium clusters GeN in the size range of 21⩽N⩽29. The basin-hopping global optimization method is employed for the search. The potential-energy surface is computed based on the plane-wave pseudopotential density functional theory. A new series of low-lying clusters is found on the basis of several generic structural motifs identified previously for silicon clusters [S. Yoo and X. C. Zeng, J. Chem. Phys. 124, 054304 (2006)] as well as for smaller-sized germanium clusters [S. Bulusu et al., J. Chem. Phys. 122, 164305 (2005)]. Among the generic motifs examined, we found that two motifs stand out in producing most low-lying clusters, namely, the six/nine motif, a puckered-hexagonal-ring Ge6 unit attached to a tricapped trigonal prism Ge9, and the six/ten motif, a puckered-hexagonal-ring Ge6 unit attached to a bicapped antiprism Ge10. The low-lying clusters obtained are all prolate in shape and their energies are appreciably lower than the near-spherical low-energy clusters. This result is consistent with the ion-mobility measurement in that medium-sized germanium clusters detected are all prolate in shape until the size N ˜65.

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, X.; Tsybeskov, L., E-mail: tsybesko@njit.edu; Kamins, T. I.

2015-12-21

Detailed studies of the structural and optical properties of axial silicon-germanium nanowire heterojunctions show that despite the 4.2% lattice mismatch between Si and Ge they can be grown without a significant density of structural defects. The lattice mismatch induced strain is partially relieved due to spontaneous SiGe intermixing at the heterointerface during growth and lateral expansion of the Ge segment of the nanowire. The mismatch in Ge and Si coefficients of thermal expansion and low thermal conductivity of Si/Ge nanowire heterojunctions are proposed to be responsible for the thermally induced stress detected under intense laser radiation in photoluminescence and Ramanmore » scattering measurements.« less

Doping of germanium nanowires grown in presence of PH3

NASA Astrophysics Data System (ADS)

Tutuc, E.; Chu, J. O.; Ott, J. A.; Guha, S.

2006-12-01

The authors study the Au-catalyzed chemical vapor growth of germanium (Ge) nanowires in the presence of phosphine (PH3), used as a dopant precursor. The device characteristics of the ensuing nanowire field effect transistors (FETs) indicate n-type, highly doped nanowires. Using a combination of different nanowire growth sequences and their FET characteristics, the authors determine that phosphorus incorporates predominately via the conformal growth, which accompanies the acicular, nanowire growth. As such, the Ge nanowires grown in the presence of PH3 contain a phosphorus doped shell and an undoped core. The authors determine the doping level in the shell to be ≃(1-4)×1019cm-3.

Bulk and surface event identification in p-type germanium detectors

NASA Astrophysics Data System (ADS)

Yang, L. T.; Li, H. B.; Wong, H. T.; Agartioglu, M.; Chen, J. H.; Jia, L. P.; Jiang, H.; Li, J.; Lin, F. K.; Lin, S. T.; Liu, S. K.; Ma, J. L.; Sevda, B.; Sharma, V.; Singh, L.; Singh, M. K.; Singh, M. K.; Soma, A. K.; Sonay, A.; Yang, S. W.; Wang, L.; Wang, Q.; Yue, Q.; Zhao, W.

2018-04-01

The p-type point-contact germanium detectors have been adopted for light dark matter WIMP searches and the studies of low energy neutrino physics. These detectors exhibit anomalous behavior to events located at the surface layer. The previous spectral shape method to identify these surface events from the bulk signals relies on spectral shape assumptions and the use of external calibration sources. We report an improved method in separating them by taking the ratios among different categories of in situ event samples as calibration sources. Data from CDEX-1 and TEXONO experiments are re-examined using the ratio method. Results are shown to be consistent with the spectral shape method.

Flexible radio-frequency single-crystal germanium switch on plastic substrates

NASA Astrophysics Data System (ADS)

Qin, Guoxuan; Cai, Tianhao; Yuan, Hao-Chih; Seo, Jung-Hun; Ma, Jianguo; Ma, Zhenqiang

2014-04-01

This Letter presents the realization and characterizations of the flexible radio-frequency (RF)/microwave switches on plastic substrates employing single-crystal germanium (Ge) nanomembranes. The fabricated flexible Ge single-pole, single-throw (SPST) switches display high frequency responses (e.g., insertion loss of <1.3 dB at up to 30 GHz and isolation >10 dB at up to ˜13 GHz). RF performance tradeoff exists for the flexible Ge switches and the major affecting parameters are determined. The flexible Ge SPST switch shows better RF property to that of the flexible Si SPST switch. Underlying mechanism is investigated by theoretical analysis and modeling of switches with different structures.

Profiling Groundwater Salt Concentrations in Mangrove Swamps and Tropical Salt Flats

NASA Astrophysics Data System (ADS)

Ridd, Peter V.; Sam, Renagi

1996-11-01

The salt concentration of groundwater in mangrove swamps is an important parameter controlling the growth of mangrove species. Extremely high salt concentrations of groundwater in tropical salt flats are responsible for the complete absence of macrophytes. Determining groundwater salt concentrations can be a very time-consuming and laborious process if conventional techniques are used. Typically, groundwater samples must be extracted for later laboratory analysis. In this work, a simple conductivity probe has been developed which may be inserted easily to a depth of 2 m into the sediment. The changes in conductivity of the sediment is due primarily to porewater salt concentration, and thus ground conductivity is useful in determining changes in groundwater salt concentrations. Using the conductivity probe, transects of sediment conductivity can be undertaken quickly. As an example of a possible application of the probe, transects of ground conductivity were taken on a mangrove swamp/saltflat system. The transects show clearly the sharp delineation in conductivity between the salt flat and mangrove swamp due to a change in groundwater salt concentrations. Horizontal and vertical salt concentration gradients of up to 50 g l -1 m -1and 150 g l -1 m -1, respectively, were found. Very sharp changes in groundwater salt concentrations at the interface between salt flats and mangroves indicate that the mangroves may be modifying the salinity of the groundwater actively.

Limits on Spin-independent Couplings of Light Dark Matter WIMPs with a p-type Point-contact Germanium Detector

NASA Astrophysics Data System (ADS)

Lin, S. T.; Wong, H. T.

New limits on spin-independent WIMP-nucleon coupling using 39.5 kg-days of data taken with a p-type point-contact germanium detector with fiducial mass of 840 g at the Kuo-Sheng Reactor Neutrino Laboratory (KSNL) is presented. Charactering and understanding the anomalous surface behaviour is of particular significance to this study. The slow rise-time of surface events is identified via software pulse shape analysis techniques. In addition, the signal-retaining and background-rejecting efficiencies are implied to clarify the actual bulk and surface events in the mixed regime at sub-keV range. Both efficiencies are evaluated with calibration sources and a novel n-type point-contact germanium detector. Efficiencies-corrected background spectra from the low-background facility at KSNL are derived. Part of the parameter space in cross-section versus WIMP-mass is probed and excluded.

Solution synthesis of germanium nanowires using a Ge+2 alkoxide precursor.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyle, Timothy J.; Tribby, Louis, J; Bunge, Scott D.

2006-02-01

A simple solution synthesis of germanium (Ge{sup 0}) nanowires under mild conditions (<400 C and 1 atm) was demonstrated using germanium 2,6 dibutylphenoxide Ge(DBP){sub 2} (1) as the precursor where DBP = OC{sub 6}H{sub 3}(C(CH{sub 3}){sub 3}){sub 2}-2,6. Compound 1, synthesized from Ge(NR{sub 2}){sub 2} where R = SiMe{sub 3} and two equivalents of DBP-H, was characterized as a mononuclear species by single crystal X-ray diffraction. Dissolution of 1 in oleylamine, followed by rapid injection into a 1-octadecene solution heated to 300 C under an atmosphere of Ar, led to the formation of Ge{sup 0} nanowires. The Ge{sup 0} nanowiresmore » were characterized by transmission electron microscopy (TEM), X-ray diffraction analysis, and Fourier transform infrared spectroscopy. These characterizations revealed that the nanowires are single crystalline in the cubic phase and coated with oleylamine surfactant. We also observed that the nanowire length (0.1 to 10 {micro}m) increases with increasing temperature (285 to 315 C) and time (5 to 60 min). Two growth mechanisms are proposed based on the TEM images intermittently taken during the growth process as a function of time: (1) self-seeding mechanism where one of two overlapping nanowires serves as a seed, while the other continues to grow as a wire and (2) self-assembly mechanism where an aggregate of small rods (< 50 nm in diameter) recrystallize on the tip of a longer wire, extending its length.« less

Comparing Algorithms for Graph Isomorphism Using Discrete- and Continuous-Time Quantum Random Walks

DOE PAGES

Rudinger, Kenneth; Gamble, John King; Bach, Eric; ...

2013-07-01

Berry and Wang [Phys. Rev. A 83, 042317 (2011)] show numerically that a discrete-time quan- tum random walk of two noninteracting particles is able to distinguish some non-isomorphic strongly regular graphs from the same family. Here we analytically demonstrate how it is possible for these walks to distinguish such graphs, while continuous-time quantum walks of two noninteracting parti- cles cannot. We show analytically and numerically that even single-particle discrete-time quantum random walks can distinguish some strongly regular graphs, though not as many as two-particle noninteracting discrete-time walks. Additionally, we demonstrate how, given the same quantum random walk, subtle di erencesmore » in the graph certi cate construction algorithm can nontrivially im- pact the walk's distinguishing power. We also show that no continuous-time walk of a xed number of particles can distinguish all strongly regular graphs when used in conjunction with any of the graph certi cates we consider. We extend this constraint to discrete-time walks of xed numbers of noninteracting particles for one kind of graph certi cate; it remains an open question as to whether or not this constraint applies to the other graph certi cates we consider.« less

Distillation and condensation of LiCl-KCl eutectic salts for a separation of pure salts from salt wastes from an electrorefining process

NASA Astrophysics Data System (ADS)

Eun, Hee Chul; Yang, Hee Chul; Lee, Han Soo; Kim, In Tae

2009-12-01

Salt separation and recovery from the salt wastes generated from a pyrochemical process is necessary to minimize the high-level waste volumes and to stabilize a final waste form. In this study, the thermal behavior of the LiCl-KCl eutectic salts containing rare earth oxychlorides or oxides was investigated during a vacuum distillation and condensation process. LiCl was more easily vaporized than the other salts (KCl and LiCl-KCl eutectic salt). Vaporization characteristics of LiCl-KCl eutectic salts were similar to that of KCl. The temperature to obtain the vaporization flux (0.1 g min -1 cm -2) was decreased by much as 150 °C by a reduction of the ambient pressure from 5 Torr to 0.5 Torr. Condensation behavior of the salt vapors was different with the ambient pressure. Almost all of the salt vapors were condensed and were formed into salt lumps during a salt distillation at the ambient pressure of 0.5 Torr and they were collected in the condensed salt storage. However, fine salt particles were formed when the salt distillation was performed at 10 Torr and it is difficult for them to be recovered. Therefore, it is thought that a salt vacuum distillation and condensation should be performed to recover almost all of the vaporized salts at a pressure below 0.5 Torr.

Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Electro-optical Applications

DTIC Science & Technology

2010-05-01

samples were dipped in an aqueous solution of iodine (I) and potassium iodide (KI) (25 gm I and 100 gm KI per liter of water [H2O] ) (16). The samples...Satterfield, C. N.; Wentworth, R. L. in Hydrogen Peroxide , Reinhold Publishing, New York, 1955, p. 370. 12 19. Kishioka, K.; Horita, S.; Ohdaria, K...germanium H2O water HBT heterojunction bipolar transistor I iodine IPA isopropal alcohol KI potassium iodide MEE metal enhanced etching

Ultra compact 45 GHz CMOS compatible Germanium waveguide photodiode with low dark current.

PubMed

DeRose, Christopher T; Trotter, Douglas C; Zortman, William A; Starbuck, Andrew L; Fisher, Moz; Watts, Michael R; Davids, Paul S

2011-12-05

We present a compact 1.3 × 4 μm2 Germanium waveguide photodiode, integrated in a CMOS compatible silicon photonics process flow. This photodiode has a best-in-class 3 dB cutoff frequency of 45 GHz, responsivity of 0.8 A/W and dark current of 3 nA. The low intrinsic capacitance of this device may enable the elimination of transimpedance amplifiers in future optical data communication receivers, creating ultra low power consumption optical communications.

Divacancy-hydrogen complexes in dislocation-free high-purity germanium. [Annealing, Hall effect, steady-state concentration energy dependence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haller, E.E.; Hubbard, G.S.; Hansen, W.L.

1976-09-01

A defect center with a single acceptor level at E/sub v/ + 0.08 eV appears in H/sub 2/-grown dislocation-free high-purity germanium. Its concentration changes reversibly upon annealing up to 650 K. By means of Hall-effect and conductivity measurements over a large temperature range the temperature dependence of the steady-state concentration between 450 and 720 K as well as the transients following changes in temperature were determined. The observed acceptor level is attributed to the divacancy-hydrogen complex V/sub 2/H. The complex reacts with hydrogen, dissolved in the Ge lattice or stored in traps, according to V/sub 2/H + H reversible V/submore » 2/H/sub 2/. An energy level associated with the divacancy-dihydrogen complex was not observed. These results are in good agreement with the idea that hydrogen in germanium forms a ''very deep donor'' (i.e., the energy level lies inside the valence band).« less

Evaluation of Segmented Amorphous-Contact Planar Germanium Detectors for Heavy-Element Research

NASA Astrophysics Data System (ADS)

Jackson, Emily G.

The challenge of improving our understanding of the very heaviest nuclei is at the forefront of contemporary low-energy nuclear physics. In the last two decades, "in-beam" spectroscopy experiments have advanced from Z=98 to Z=104, Rutherfordium, allowing insights into the dynamics of the fission barrier, high-order deformations, and pairing correlations. However, new detector technologies are needed to advance to even heavier nuclei. This dissertation is aimed at evaluating one promising new technology; large segmented planar germanium wafers for this area of research. The current frontier in gamma-ray spectroscopy involves large-volume (>9 cm thick) coaxial detectors that are position sensitive and employ gamma-ray "tracking". In contrast, the detectors assessed in this dissertation are relatively thin (~1 cm) segmented planar wafers with amorphous-germanium strip contacts that can tolerate extremely high gamma-ray count rates, and can accommodate hostile neutron fluxes. They may be the only path to heavier "in-beam" spectroscopy with production rates below 1 nanobarn. The resiliency of these detectors against neutron-induced damage is examined. Two detectors were deliberately subjected to a non-uniform neutron fluence leading to considerable degradation of performance. The neutrons were produced using the 7Li(p, n)7Be reaction at the UMass Lowell Van-de-Graaff accelerator with a 3.7-MeV proton beam incident on a natural Li target. The energy of the neutrons emitted at zero degrees was 2.0 MeV, close to the mean energy of the fission neutron spectrum, and each detector was exposed to a fluence >3.6 x109 n/cm2. A 3-D software "trap-corrector" gain-matching algorithm considerably restored the overall performance. Other neutron damage mitigation tactics were explored including over biasing the detector and flooding the detector with a high gamma-ray count rate. Various annealing processes to remove neutron damage were investigated. An array of very large diameter

Femtosecond tracking of carrier relaxation in germanium with extreme ultraviolet transient reflectivity

NASA Astrophysics Data System (ADS)

Kaplan, Christopher J.; Kraus, Peter M.; Ross, Andrew D.; Zürch, Michael; Cushing, Scott K.; Jager, Marieke F.; Chang, Hung-Tzu; Gullikson, Eric M.; Neumark, Daniel M.; Leone, Stephen R.

2018-05-01

Extreme ultraviolet (XUV) transient reflectivity around the germanium M4 ,5 edge (3 d core-level to valence transition) at 30 eV is advanced to obtain the transient dielectric function of crystalline germanium [100] on femtosecond to picosecond time scales following photoexcitation by broadband visible-to-infrared (VIS/NIR) pulses. By fitting the transient dielectric function, carrier-phonon induced relaxations are extracted for the excited carrier distribution. The measurements reveal a hot electron relaxation rate of 3.2 ±0.2 ps attributed to the X -L intervalley scattering and a hot hole relaxation rate of 600 ±300 fs ascribed to intravalley scattering within the heavy hole (HH) band, both in good agreement with previous work. An overall energy shift of the XUV dielectric function is assigned to a thermally induced band gap shrinkage by formation of acoustic phonons, which is observed to be on a timescale of 4-5 ps, in agreement with previously measured optical phonon lifetimes. The results reveal that the transient reflectivity signal at an angle of 66∘ with respect to the surface normal is dominated by changes to the real part of the dielectric function, due to the near critical angle of incidence of the experiment (66∘-70∘) for the range of XUV energies used. This work provides a methodology for interpreting XUV transient reflectivity near core-level transitions, and it demonstrates the power of the XUV spectral region for measuring ultrafast excitation dynamics in solids.

Secondary ion formation during electronic and nuclear sputtering of germanium

NASA Astrophysics Data System (ADS)

Breuer, L.; Ernst, P.; Herder, M.; Meinerzhagen, F.; Bender, M.; Severin, D.; Wucher, A.

2018-06-01

Using a time-of-flight mass spectrometer attached to the UNILAC beamline located at the GSI Helmholtz Centre for Heavy Ion Research, we investigate the formation of secondary ions sputtered from a germanium surface under irradiation by swift heavy ions (SHI) such as 5 MeV/u Au by simultaneously recording the mass spectra of the ejected secondary ions and their neutral counterparts. In these experiments, the sputtered neutral material is post-ionized via single photon absorption from a pulsed, intensive VUV laser. After post-ionization, the instrument cannot distinguish between secondary ions and post-ionized neutrals, so that both signals can be directly compared in order to investigate the ionization probability of different sputtered species. In order to facilitate an in-situ comparison with typical nuclear sputtering conditions, the system is also equipped with a conventional rare gas ion source delivering a 5 keV argon ion beam. For a dynamically sputter cleaned surface, it is found that the ionization probability of Ge atoms and Gen clusters ejected under electronic sputtering conditions is by more than an order of magnitude higher than that measured for keV sputtered particles. In addition, the mass spectra obtained under SHI irradiation show prominent signals of GenOm clusters, which are predominantly detected as positive or negative secondary ions. From the m-distribution for a given Ge nuclearity n, one can deduce that the sputtered material must originate from a germanium oxide matrix with approximate GeO stoichiometry, probably due to residual native oxide patches even at the dynamically cleaned surface. The results clearly demonstrate a fundamental difference between the ejection and ionization mechanisms in both cases, which is interpreted in terms of corresponding model calculations.

Arsenic, barium, germanium, tin, dimethylsulfide and nutrient biogeochemistry in Charlotte Harbor, Florida, a phosphorus-enriched estuary

NASA Astrophysics Data System (ADS)

Froelich, P. N.; Kaul, L. W.; Byrd, J. T.; Andreae, M. O.; Roe, K. K.

1985-03-01

Concentrations of dissolved nutrients (NO 3, PO 4, Si), germanium species, arsenic species, tin, barium, dimethylsulfide and related parameters were measured along the salinity gradient in Charlotte Harbor. Phosphate enrichment from the phosphate industry on the Peace River promotes a productive diatom bloom near the river mouth where NO 3 and Si are completely consumed. Inorganic germanium is completely depleted in this bloom by uptake into biogenic opal. The Ge/Si ratio taken up by diatoms is about 0·7 × 10 -6, the same as that provided by the river flux, confirming that siliceous organisms incorporate germanium as an accidental trace replacement for silica. Monomethylgermanium and dimethylgermanium concentrations are undetectable in the Peace River, and increase linearly with increasing salinity to the seawater end of the bay, suggesting that these organogermanium species behave conservatively in estuaries, and are neither produced nor consumed during estuarine biogenic opal formation or dissolution. Inorganic arsenic displays slight removal in the bloom. Monomethylarsenic is produced both in the bloom and in mid-estuary, while dimethylarsenic is conservative in the bloom but produced in mid-estuary. The total production of methylarsenicals within the bay approximately balances the removal of inorganic arsenic, suggesting that most biological arsenic uptake in the estuary is biomethylated and released to the water column. Dimethylsulfide increases with increasing salinity in the estuary and shows evidence of removal, probably both by degassing and by microbial consumption. An input of DMS is observed in the central estuary. The behavior of total dissolvable tin shows no biological activity in the bloom or in mid-estuary, but does display a low-salinity input signal that parallels dissolved organic material, perhaps suggesting an association between tin and DOM. Barium displays dramatic input behavior at mid-salinities, probably due to slow release from clays

A Compton scattering setup for pulse shape discrimination studies in germanium detectors.

PubMed

von Sturm, K; Belogurov, S; Brugnera, R; Garfagnini, A; Lippi, I; Modenese, L; Rosso, D; Turcato, M

2017-07-01

Pulse shape discrimination is an important handle to improve sensitivity in low background experiments. A dedicated setup was built to investigate the response of high-purity germanium detectors to single Compton scattered events. Using properly collimated γ-ray sources, it is possible to select events with known interaction location. The aim is to correlate the position dependent signal shape with geometrical and electrical properties of the detector. We report on design and performance of the setup with a first look on data. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lattice dynamics and thermoelectric properties of nanocrystalline silicon-germanium alloys

DOE PAGES

Claudio, Tania; Stein, Niklas; Peterman, Nils; ...

2015-10-26

The lattice dynamics and thermoelectric properties of sintered phosphorus-doped nanostructured silicon- germanium alloys obtained by gas-phase synthesis were studied. Measurements of the density of phonon states by inelastic neutron scattering were combined with measurements of the elastic constants and the low- temperature heat capacity. A strong influence of nanostructuring and alloying on the lattice dynamics was observed. The thermoelectric transport properties of samples with different doping as well as samples sintered at different temperature were characterized between room temperature and 1000C. A peak figure of merit zT = 0:88 at 900C is observed and comparatively insensitive to the aforementioned param-more » eter variations.« less

Bridgman Growth of Germanium Crystals in a Rotating Magnetic Field

NASA Technical Reports Server (NTRS)

Volz, M. P.; Szofran, F. R.; Cobb, S. D.; Schweizer, M.; Walker, J. S.

2005-01-01

A series of (100)-oriented gallium-doped germanium crystals has been grown by the vertical Bridgman method and under the influence of a rotating magnetic field (RMF). Time-dependent flow instabilities occur when the critical magnetic Taylor number (Tm(sup c)) is exceeded, and this can be observed by noting the appearance of striations in the grown crystals. Tm(sup c) decreases as the aspect ratio of the melt increases, and approaches the theoretical limit expected for an infinite cylinder. Intentional interface demarcations are introduced by pulsing the RMF on and off The RMF has a marked affect on the interface shape, changing it from concave to nearly flat as the RMF strength is increased.

Molten Salt Promoting Effect in Double Salt CO2 Absorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Keling; Li, Xiaohong S.; Chen, Haobo

2016-01-01

The purpose of this paper is to elaborate on the concept of molten salts as catalysts for CO2 absorption by MgO, and extend these observations to the MgO-containing double salt oxides. We will show that the phenomena involved with CO2 absorption by MgO and MgO-based double salts are similar and general, but with some important differences. This paper focuses on the following key concepts: i) identification of conditions that favor or disfavor participation of isolated MgO during double salt absorption, and investigation of methods to increase the absorption capacity of double salt systems by including MgO participation; ii) examination ofmore » the relationship between CO2 uptake and melting point of the promoter salt, leading to the recognition of the role of pre-melting (surface melting) in these systems; and iii) extension of the reaction pathway model developed for the MgO-NaNO3 system to the double salt systems. This information advances our understanding of MgO-based CO2 absorption systems for application with pre-combustion gas streams.« less

Creating ligand-free silicon germanium alloy nanocrystal inks.

PubMed

Erogbogbo, Folarin; Liu, Tianhang; Ramadurai, Nithin; Tuccarione, Phillip; Lai, Larry; Swihart, Mark T; Prasad, Paras N

2011-10-25

Particle size is widely used to tune the electronic, optical, and catalytic properties of semiconductor nanocrystals. This contrasts with bulk semiconductors, where properties are tuned based on composition, either through doping or through band gap engineering of alloys. Ideally, one would like to control both size and composition of semiconductor nanocrystals. Here, we demonstrate production of silicon-germanium alloy nanoparticles by laser pyrolysis of silane and germane. We have used FTIR, TEM, XRD, EDX, SEM, and TOF-SIMS to conclusively determine their structure and composition. Moreover, we show that upon extended sonication in selected solvents, these bare nanocrystals can be stably dispersed without ligands, thereby providing the possibility of using them as an ink to make patterned films, free of organic surfactants, for device fabrication. The engineering of these SiGe alloy inks is an important step toward the low-cost fabrication of group IV nanocrystal optoelectronic, thermoelectric, and photovoltaic devices.

The SENSE-Isomorphism Theoretical Image Voxel Estimation (SENSE-ITIVE) Model for Reconstruction and Observing Statistical Properties of Reconstruction Operators

PubMed Central

Bruce, Iain P.; Karaman, M. Muge; Rowe, Daniel B.

2012-01-01

The acquisition of sub-sampled data from an array of receiver coils has become a common means of reducing data acquisition time in MRI. Of the various techniques used in parallel MRI, SENSitivity Encoding (SENSE) is one of the most common, making use of a complex-valued weighted least squares estimation to unfold the aliased images. It was recently shown in Bruce et al. [Magn. Reson. Imag. 29(2011):1267–1287] that when the SENSE model is represented in terms of a real-valued isomorphism, it assumes a skew-symmetric covariance between receiver coils, as well as an identity covariance structure between voxels. In this manuscript, we show that not only is the skew-symmetric coil covariance unlike that of real data, but the estimated covariance structure between voxels over a time series of experimental data is not an identity matrix. As such, a new model, entitled SENSE-ITIVE, is described with both revised coil and voxel covariance structures. Both the SENSE and SENSE-ITIVE models are represented in terms of real-valued isomorphisms, allowing for a statistical analysis of reconstructed voxel means, variances, and correlations resulting from the use of different coil and voxel covariance structures used in the reconstruction processes to be conducted. It is shown through both theoretical and experimental illustrations that the miss-specification of the coil and voxel covariance structures in the SENSE model results in a lower standard deviation in each voxel of the reconstructed images, and thus an artificial increase in SNR, compared to the standard deviation and SNR of the SENSE-ITIVE model where both the coil and voxel covariances are appropriately accounted for. It is also shown that there are differences in the correlations induced by the reconstruction operations of both models, and consequently there are differences in the correlations estimated throughout the course of reconstructed time series. These differences in correlations could result in meaningful

A first-principles core-level XPS study on the boron impurities in germanium crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamauchi, Jun; Yoshimoto, Yoshihide; Suwa, Yuji

2013-12-04

We systematically investigated the x-ray photoelectron spectroscopy (XPS) core-level shifts and formation energies of boron defects in germanium crystals and compared the results to those in silicon crystals. Both for XPS core-level shifts and formation energies, relationship between defects in Si and Ge is roughly linear. From the similarity in the formation energy, it is expected that the exotic clusters like icosahedral B12 exist in Ge as well as in Si.

Ductile-regime turning of germanium and silicon

NASA Technical Reports Server (NTRS)

Blake, Peter N.; Scattergood, Ronald O.

1989-01-01

Single-point diamond turning of silicon and germanium was investigated in order to clarify the role of cutting depth in coaxing a ductile chip formation in normally brittle substances. Experiments based on the rapid withdrawal of the tool from the workpiece have shown that microfracture damage is a function of the effective depth of cut (as opposed to the nominal cutting depth). In essence, damage created by the leading edge of the tool is removed several revolutions later by lower sections of the tool edge, where the effective cutting depth is less. It appears that a truly ductile cutting response can be achieved only when the effective cutting depth, or critical chip thickness, is less than about 20 nm. Factors such as tool rake angle are significant in that they will affect the actual value of the critical chip thickness for transition from brittle to ductile response. It is concluded that the critical chip thickness is an excellent parameter for measuring the effects of machining conditions on the ductility of the cut and for designing tool-workpiece geometry in both turning and grinding.

Deformation of allochthonous salt and evolution of related salt-structural systems, eastern Louisiana Gulf Coast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuster, D.C.

1996-12-31

Salt tectonics in the northern Gulf of Mexico involves both vertical diapirism and lateral silling or flow of salt into wings and tablets (sheets). Combinations of these two modes of salt deformation, concurrent with sediment loading and salt evacuation, have produced complex structures in the coastal and offshore region of southeastern Louisiana, a prolific oil and gas province. Many large growth faults and salt domes in the study area root into intra-Tertiary salt welds that were formerly occupied by allochthonous salt tablets. Two end-member structural systems involving evacuation of former tabular salt are recognized: roho systems and stepped counter-regional systems.more » Both end-member systems share a similar multi-staged evolution, including (1) initial formation of a south-leaning salt dome or wall sourced from the Jurassic salt level; (2) progressive development into a semi-tabular allochthonous salt body; and (3) subsequent loading, evacuation, and displacement of the tabular salt into secondary domes. In both systems, it is not uncommon to find salt displaced as much as 16-24 km south of its autochthonous source, connected by a horizontal salt weld to an updip, deflated counter-regional feeder. Although both end-member structural systems may originate before loading of allochthonous salt having grossly similar geometry, their final structural configurations after loading and salt withdrawal are distinctly different. Roho systems are characterized by large-displacement, listric, south-dipping growth faults that sole into intra-Tertiary salt welds marked by high-amplitude reflections continuous with residual salt masses. Salt from the former salt tablets has been loaded and squeezed laterally and downdip. Stepped counter-regional systems, in contrast, comprise large salt domes and adjacent large-displacement, north-dipping growth faults that sole into intra-Tertiary salt welds before stepping down again farther north.« less

High-Resolution Gamma-Ray Imaging Measurements Using Externally Segmented Germanium Detectors

NASA Technical Reports Server (NTRS)

Callas, J.; Mahoney, W.; Skelton, R.; Varnell, L.; Wheaton, W.

1994-01-01

Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy has been demonstrated using an externally segmented germanium sensor. The system employs a single high-purity coaxial detector with its outer electrode segmented into 5 distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A non-negative, linear least-squares algorithm was then employed to reconstruct a 2-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process.

New iodide-based molten salt systems for high temperature molten salt batteries

NASA Astrophysics Data System (ADS)

Fujiwara, Syozo; Kato, Fumio; Watanabe, Syouichiro; Inaba, Minoru; Tasaka, Akimasa

Novel multi-component molten salt systems containing iodides, LiF-LiBr-LiI, LiF-NaBr-LiI, and LiF-LiCl-LiBr-LiI, were investigated for use as electrolytes in high temperature molten salt batteries to improve the discharge rate-capability. The iodide-based molten salts showed higher ionic conductivity (∼3 S cm -1 at 500 °C) than conventional LiCl-KCl, and had low enough melting points (below 400 °C) that can be used in practical high temperature molten salt batteries. The iodide-based salts showed instability at temperatures higher than 280 °C in dried air. The decomposition mechanism of iodide-based molten salts was discussed, and it was found that elimination of oxygen from the environment is effective to stabilize the iodide-based molten salts at high temperatures.

Effect of salt intake on beat-to-beat blood pressure nonlinear dynamics and entropy in salt-sensitive versus salt-protected rats.

PubMed

Fares, Souha A; Habib, Joseph R; Engoren, Milo C; Badr, Kamal F; Habib, Robert H

2016-06-01

Blood pressure exhibits substantial short- and long-term variability (BPV). We assessed the hypothesis that the complexity of beat-to-beat BPV will be differentially altered in salt-sensitive hypertensive Dahl rats (SS) versus rats protected from salt-induced hypertension (SSBN13) maintained on high-salt versus low-salt diet. Beat-to-beat systolic and diastolic BP series from nine SS and six SSBN13 rats (http://www.physionet.org) were analyzed following 9 weeks on low salt and repeated after 2 weeks on high salt. BP complexity was quantified by detrended fluctuation analysis (DFA), short- and long-range scaling exponents (αS and αL), sample entropy (SampEn), and traditional standard deviation (SD) and coefficient of variation (CV(%)). Mean systolic and diastolic BP increased on high-salt diet (P < 0.01) particularly for SS rats. SD and CV(%) were similar across groups irrespective of diet. Salt-sensitive and -protected rats exhibited similar complexity indices on low-salt diet. On high salt, (1) SS rats showed increased scaling exponents or smoother, systolic (P = 0.007 [αL]) and diastolic (P = 0.008 [αL]) BP series; (2) salt-protected rats showed lower SampEn (less complex) systolic and diastolic BP (P = 0.046); and (3) compared to protected SSBN13 rats, SS showed higher αL for systolic (P = 0.01) and diastolic (P = 0.005) BP Hypertensive SS rats are more susceptible to high salt with a greater rise in mean BP and reduced complexity. Comparable mean pressures in sensitive and protective rats when on low-salt diet coupled with similar BPV dynamics suggest a protective role of low-salt intake in hypertensive rats. This effect likely reflects better coupling of biologic oscillators. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Assessment of Bioavailable Concentrations of Germanium and Rare Earth Elements in the Rhizosphere of White Lupin (Lupinus albus L.)

NASA Astrophysics Data System (ADS)

Wiche, Oliver; Fischer, Ronny; Moschner, Christin; Székely, Balázs

2015-04-01

Concentrations of Germanium (Ge) and Rare Earth Elements in soils are estimated at 1.5 mg kg -1 (Ge), 25 mg kg -1 (La) and 20 mg kg -1 (Nd), which are only roughly smaller than concentrations of Pb and Zn. Germanium and rare earth elements are thus not rare but widely dispersed in soils and therefore up to date, only a few minable deposits are available. An environmental friendly and cost-effective way for Ge and rare earth element production could be phytomining. However, the most challenging part of a phytomining of these elements is to increase bioavailable concentrations of the elements in soils. Recent studies show, that mixed cultures with white lupine or other species with a high potential to mobilize trace metals in their rhizosphere due to an acidification of the soil and release of organic acids in the root zone could be a promising tool for phytomining. Complexation of Ge and rare earth elements by organic acids might play a key role in controlling bioavailability to plants as re-adsorption on soil particles and precipitation is prevented and thus, concentrations in the root zone of white lupine increase. This may also allow the complexes to diffuse along a concentration gradient to the roots of mixed culture growing species leading to enhanced plant uptake. However, to optimize mixed cultures it would be interesting to know to which extend mobilization of trace metals is dependent from chemical speciation of elements in soil due to the interspecific interaction of roots. A method for the identification of complexes of germanium and rare earth elements with organic acids, predominantly citric acid in the rhizosphere of white lupine was developed and successfully tested. The method is based on coupling of liquid chromatography with ICP-MS using a zic-philic column (SeQuant). As a preliminary result, we were able to show that complexes of germanium with citric acid exist in the rhizosphere of white lupin, what may contribute to the bioavailability of this

Electrolyte salts for power sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doddapaneni, Narayan; Ingersoll, David

Electrolyte salts for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts.

Spin Qubits in Germanium Structures with Phononic Gap

NASA Technical Reports Server (NTRS)

Smelyanskiy, V. N.; Vasko, F. T.; Hafiychuk, V. V.; Dykman, M. I.; Petukhov, A. G.

2014-01-01

We propose qubits based on shallow donor electron spins in germanium structures with phononic gap. We consider a phononic crystal formed by periodic holes in Ge plate or a rigid cover / Ge layer / rigid substrate structure with gaps approximately a few GHz. The spin relaxation is suppressed dramatically, if the Zeeman frequency omegaZ is in the phononic gap, but an effective coupling between the spins of remote donors via exchange of virtual phonons remains essential. If omegaZ approaches to a gap edge in these structures, a long-range (limited by detuning of omegaZ) resonant exchange interaction takes place. We estimate that ratio of the exchange integral to the longitudinal relaxation rate exceeds 10(exp 5) and lateral scale of resonant exchange 0.1 mm. The exchange contribution can be verified under microwave pumping through oscillations of spin echo signal or through the differential absorption measurements. Efficient manipulation of spins due to the Rabi oscillations opens a new way for quantum information applications.

Development of a Germanium Small-Animal SPECT System

NASA Astrophysics Data System (ADS)

Johnson, Lindsay C.; Ovchinnikov, Oleg; Shokouhi, Sepideh; Peterson, Todd E.

2015-10-01

Advances in fabrication techniques, electronics, and mechanical cooling systems have given rise to germanium detectors suitable for biomedical imaging. We are developing a small-animal SPECT system that uses a double-sided Ge strip detector. The detector's excellent energy resolution may help to reduce scatter and simplify processing of multi-isotope imaging, while its ability to measure depth of interaction has the potential to mitigate parallax error in pinhole imaging. The detector's energy resolution is <; 1% FWHM at 140 keV and its spatial resolution is approximately 1.5 mm FWHM. The prototype system described has a single-pinhole collimator with a 1-mm diameter and a 70-degree opening angle with a focal length variable between 4.5 and 9 cm. Phantom images from the gantry-mounted system are presented, including the NEMA NU-2008 phantom and a hot-rod phantom. Additionally, the benefit of energy resolution is demonstrated by imaging a dual-isotope phantom with 99mTc and 123I without cross-talk correction.

Germanium Based Field-Effect Transistors: Challenges and Opportunities

PubMed Central

Goley, Patrick S.; Hudait, Mantu K.

2014-01-01

The performance of strained silicon (Si) as the channel material for today’s metal-oxide-semiconductor field-effect transistors may be reaching a plateau. New channel materials with high carrier mobility are being investigated as alternatives and have the potential to unlock an era of ultra-low-power and high-speed microelectronic devices. Chief among these new materials is germanium (Ge). This work reviews the two major remaining challenges that Ge based devices must overcome if they are to replace Si as the channel material, namely, heterogeneous integration of Ge on Si substrates, and developing a suitable gate stack. Next, Ge is compared to compound III-V materials in terms of p-channel device performance to review how it became the first choice for PMOS devices. Different Ge device architectures, including surface channel and quantum well configurations, are reviewed. Finally, state-of-the-art Ge device results and future prospects are also discussed. PMID:28788569

Balancing sub- and supra-salt strain in salt-influenced rifts: Implications for extension estimates

NASA Astrophysics Data System (ADS)

Coleman, Alexander J.; Jackson, Christopher A.-L.; Duffy, Oliver B.

2017-09-01

The structural style of salt-influenced rifts may differ from those formed in predominantly brittle crust. Salt can decouple sub- and supra-salt strain, causing sub-salt faults to be geometrically decoupled from, but kinematically coupled to and responsible for, supra-salt forced folding. Salt-influenced rifts thus contain more folds than their brittle counterparts, an observation often ignored in extension estimates. Fundamental to determining whether sub- and supra-salt structures are kinematically coherent, and the relative contributions of thin- (i.e. gravity-driven) and thick-skinned (i.e. whole-plate stretching) deformation to accommodating rift-related strain, is our ability to measure extension at both structural levels. We here use published physical models of salt-influenced extension to show that line-length estimates yield more accurate values of sub- and supra-salt extension compared to fault-heave, before applying these methods to seismic data from the Halten Terrace, offshore Norway. We show that, given the abundance of ductile deformation in salt-influenced rifts, significant amounts of extension may be ignored, leading to the erroneous interpretations of thin-skinned, gravity-gliding. If a system is kinematically coherent, supra-salt structures can help predict the occurrence and kinematics of sub-salt faults that may be poorly imaged and otherwise poorly constrained.

Reducing the Salt Added to Takeaway Food: Within-Subjects Comparison of Salt Delivered by Five and 17 Holed Salt Shakers in Controlled Conditions

PubMed Central

Goffe, Louis; Wrieden, Wendy; Penn, Linda; Hillier-Brown, Frances; Lake, Amelia A.; Araujo-Soares, Vera; Summerbell, Carolyn; White, Martin; Adamson, Ashley J.

2016-01-01

Objectives To determine if the amount of salt delivered by standard salt shakers commonly used in English independent takeaways varies between those with five and 17 holes; and to determine if any differences are robust to variations in: the amount of salt in the shaker, the length of time spent shaking, and the person serving. Design Four laboratory experiments comparing the amount of salt delivered by shakers. Independent variables considered were: type of shaker used (five or 17 holes), amount of salt in the shaker before shaking commences (shaker full, half full or nearly empty), time spent shaking (3s, 5s or 10s), and individual serving. Setting Controlled, laboratory, conditions. Participants A quota-based convenience sample of 10 participants (five women) aged 18–59 years. Main Outcome Measures Amount of salt delivered by salt shakers. Results Across all trials, the 17 holed shaker delivered a mean (SD) of 7.86g (4.54) per trial, whilst the five holed shaker delivered 2.65g (1.22). The five holed shaker delivered a mean of 33.7% of the salt of the 17 holed shaker. There was a significant difference in salt delivered between the five and 17 holed salt shakers when time spent shaking, amount of salt in the shaker and participant were all kept constant (p<0.001). This difference was robust to variations in the starting weight of shakers, time spent shaking and participant shaking (pssalt shakers have the potential to reduce the salt content of takeaway food, and particularly food from Fish & Chip shops, where these shakers are particularly used. Further research will be required to determine the effects of this intervention on customers’ salt intake with takeaway food and on total dietary salt intake. PMID:27668747

Measurement of energy transitions for the decay radiations of 75Ge and 69Ge in a high purity germanium detector

NASA Astrophysics Data System (ADS)

Aydın, Güral; Usta, Metin; Oktay, Adem

2018-06-01

Photoactivation experiments have a wide range of application areas in nuclear, particle physics, and medical physics such as measuring energy levels and half-lifes of nuclei, experiments for understanding imaging methods in medicine, isotope production for patient treatment, radiation security and transportation, radiation therapy, and astrophysics processes. In this study, some energy transition values of the decay radiations of 75Ge and 69Ge, which are the products of photonuclear reactions (γ, n) with germanium isotopes (75Ge and 69Ge), were measured. The gamma spectrum as a result of atomic transitions were analysed by using a high purity semiconductor germanium detector and the energy transition values which are presented here were compared with the ones which are the best in literature. It was observed that the results presented are in agreement with literature in error range and some results have better precisions.

Germanium diffusion with vapor-phase GeAs and oxygen co-incorporation in GaAs

NASA Astrophysics Data System (ADS)

Wang, Wei-Fu; Cheng, Kai-Yuan; Hsieh, Kuang-Chien

2018-01-01

Vapor-phase germanium diffusion has been demonstrated in Zn-doped and semi-insulating GaAs in sealed ampoules with GeAs powders and excess arsenic. Secondary-ion-mass spectroscopy (SIMS) profiles indicate the presence of unintentional co-incorporation of oxygen in high densities (>1017/cm3) along with diffused germanium donors whose concentration (>>1018/cm3) determined by electro-chemical capacitance-voltage (ECV) profiler shows significant compensation near the surface. The source of oxygen mainly originates from the GeAs powder which contains Ge-O surface oxides. Variable-temperature photoluminescence (PL) shows that in GeAs-diffused samples, a broad peak ranging from 0.86-1.38 eV with the peak position around 1.1 eV predominates at low temperatures while the near band-edge luminescence quenches. The broad band is attributed to the GeGa-VGa self-activated (SA) centers possibly associated with nearby oxygen-related defect complex, and its luminescence persists up to 400 K. The configurational-coordinate modeling finds that the SA defect complex has a thermal activation energy of 150-180 meV and a vibrational energy 26.8 meV. The presence of oxygen does not much affect the SA emission intensity but may have influenced the peak position, vibration frequency and activation energy as compared to other common donor-VGa defects in GaAs.

Insights into thermal diffusion of germanium and oxygen atoms in HfO{sub 2}/GeO{sub 2}/Ge gate stacks and their suppressed reaction with atomically thin AlO{sub x} interlayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogawa, Shingo, E-mail: Shingo-Ogawa@trc.toray.co.jp; Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871; Asahara, Ryohei

2015-12-21

The thermal diffusion of germanium and oxygen atoms in HfO{sub 2}/GeO{sub 2}/Ge gate stacks was comprehensively evaluated by x-ray photoelectron spectroscopy and secondary ion mass spectrometry combined with an isotopic labeling technique. It was found that {sup 18}O-tracers composing the GeO{sub 2} underlayers diffuse within the HfO{sub 2} overlayers based on Fick's law with the low activation energy of about 0.5 eV. Although out-diffusion of the germanium atoms through HfO{sub 2} also proceeded at the low temperatures of around 200 °C, the diffusing germanium atoms preferentially segregated on the HfO{sub 2} surfaces, and the reaction was further enhanced at high temperatures withmore » the assistance of GeO desorption. A technique to insert atomically thin AlO{sub x} interlayers between the HfO{sub 2} and GeO{sub 2} layers was proven to effectively suppress both of these independent germanium and oxygen intermixing reactions in the gate stacks.« less

Great Salt Lake and Bonneville Salt Flats, UT, USA

NASA Technical Reports Server (NTRS)

1992-01-01

This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.

Great Salt Lake and Bonneville Salt Flats, UT, USA

NASA Image and Video Library

1992-04-02

This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.

[Historical roles of salt].

PubMed

Ritz, E; Ritz, C

2004-12-17

Recently increasing evidence has been provided pointing to a close relation of salt consumption to hypertension as well as to target organ damage. It is interesting to note that the discussion concerning salt is unusually emotional. This may be explained, at least in part, by the fact that since ancient times salt had deep symbolic significance, as exemplified, mostly subconsciously, by many customs and expressions still in current use. In the past salt was essential to preserve food. The past importance of salt as a commodity can well be compared with that of oil today. These and further historical aspects of the role of salt are briefly dealt with in this article.

Cationic aza-macrocyclic complexes of germanium(II) and silicon(IV).

PubMed

Everett, Matthew; Jolleys, Andrew; Levason, William; Light, Mark E; Pugh, David; Reid, Gillian

2015-12-28

[GeCl2(dioxane)] reacts with the neutral aza-macrocyclic ligands L, L = Me3tacn (1,4,7-trimethyl-1,4,7-triazacyclononane), Me4cyclen (1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane) or Me4cyclam (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and two mol. equiv. of Me3SiO3SCF3 in thf solution to yield the unusual and hydrolytically very sensitive [Ge(L)][O3SCF3]2 as white solids in moderate yield. Using shorter reaction times [Ge(Me3tacn)]Cl2 and [Ge(Me3tacn)]Cl[O3SCF3] were also isolated; the preparation of [Ge(Me4cyclen)][GeCl3]2 is also described. The structures of the Me3tacn complexes show κ(3)-coordination of the macrocycle, with the anions interacting only weakly to produce very distorted five- or six-coordination at germanium. In contrast, the structure of [Ge(Me4cyclen)][O3SCF3]2 shows no anion interactions, and a distorted square planar geometry at germanium from coordination to the tetra-aza macrocycle. Crystal structures of the Si(iv) complexes, [SiCl3(Me3tacn)]Y (Y = O3SCF3, BAr(F); [B{3,5-(CF3)2C6H3}4]) and [SiHCl2(Me3tacn)][BAr(F)], obtained from reaction of SiCl4 or SiHCl3 with Me3tacn, followed by addition of either Me3SiO3SCF3 or Na[BAr(F)], contain distorted octahedral cations, with facialκ(3)-coordinated Me3tacn. The open-chain triamine, Me2NCH2CH2N(Me)CH2CH2NMe2 (pmdta), forms [SiCl3(pmdta)][BAr(F)] and [SiBr3(pmdta)][BAr(F)] under similar conditions, containing mer-octahedral cations.

Water purification using organic salts

DOEpatents

Currier, Robert P.

2004-11-23

Water purification using organic salts. Feed water is mixed with at least one organic salt at a temperature sufficiently low to form organic salt hydrate crystals and brine. The crystals are separated from the brine, rinsed, and melted to form an aqueous solution of organic salt. Some of the water is removed from the aqueous organic salt solution. The purified water is collected, and the remaining more concentrated aqueous organic salt solution is reused.

Bridgman Growth of Germanium Crystals in a Rotating Magnetic Field

NASA Technical Reports Server (NTRS)

Volz, M. P.; Walker, J. S.; Schweizer, M.; Cobb, S. D.; Szofran, F. R.

2004-01-01

A series of (100)-oriented gallium-doped germanium crystals have been grown by the Bridgman method and under the influence of a rotating magnetic field (RMF). Time-dependent flow instabilities occur when the critical magnetic Taylor number (Tm(sup c) is exceeded, and this can be observed by noting the appearance of striations in the grown crystals. The experimental data indicate that Tm(sup c) increases as the aspect ratio of the melt decreases. Modeling calculations predicting Tm(sup c) as a function of aspect ratio are in reasonable agreement with the experimental data. The RMF has a marked affect on the interface shape, changing it from concave to nearly flat as the RMF strength is increased. Also, by pulsing the RMF on and off, it is shown that intentional interface demarcations can be introduced.

Bridgman Growth of Germanium Crystals in a Rotating Magnetic Field

NASA Technical Reports Server (NTRS)

Volz, M. P.; Schweizer, M.; Cobb, S. D.; Walker, J. S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

2002-01-01

A series of (100)-oriented gallium-doped germanium crystals have been grown by the Bridgman method and under the influence of a rotating magnetic field (RMF). The RMF has a marked affect on the interface shape, changing it from concave to nearly flat. The onset of time-dependent flow instabilities occurs when the critical magnetic Taylor number is exceeded, and this can be observed by noting the appearance of striations in the grown crystals. The critical magnetic Taylor number is a sensitive function of the aspect ratio and, as the crystal grows under a constant applied magnetic field, the induced striations change from nonperiodic to periodic, undergo a period-doubling transition, and then cease to exist. Also, by pulsing the RMF on and off, it is shown that intentional interface demarcations can be introduced.

Method of manufacturing a niobium-aluminum-germanium superconductive material

DOEpatents

Wang, John L.; Pickus, Milton R.; Douglas, Kent E.

1980-01-01

A method for manufacturing flexible Nb.sub.3 (Al,Ge) multifilamentary superconductive material in which a sintered porous niobium compact is infiltrated with an aluminum-germanium alloy and thereafter deformed and heat treated in a series of steps at different successively higher temperatures preferably below 1000.degree. C. to produce filaments composed of Nb.sub.3 (Al,G3) within the compact. By avoiding temperatures in excess of 1000.degree. C. during the heat treatment, cladding material such as copper can be applied to facilitate a deformation step preceding the heat treatment and can remain in place through the heat treatment to also serve as a temperature stabilizer for supeconductive material produced. Further, these lower heat treatment temperatures favor formation of filaments with reduced grain size and, hence with more grain boundaries which in turn increase the current-carrying capacity of the superconductive material.

A universal salt model based on under-ground precipitation of solid salts due to supercritical water `out-salting'

NASA Astrophysics Data System (ADS)

Rueslåtten, H.; Hovland, M. T.

2010-12-01

One of the common characteristics of planets Earth and Mars is that both host water (H2O) and large accumulations of salt. Whereas Earth’s surface-environment can be regarded as ‘water-friendly’ and ‘salt hostile’, the reverse can be said for the surface of Mars. This is because liquid water is stable on Earth, and the atmosphere transports humidity around the globe, whereas on planet Mars, liquid water is unstable, rendering the atmosphere dry and, therefore, ‘salt-friendly’. The riddle as to how the salt accumulated in various locations on those two planets, is one of long-lasting and great debate. The salt accumulations on Earth are traditionally termed ‘evaporites’, meaning that they formed as a consequence of the evaporation of large masses of seawater. How the accumulations on Mars formed is much harder to explain, as an ocean only existed briefly. Although water molecules and OH-groups may exist in abundance in bound form (crystal water, adsorbed water, etc.), the only place where free water is expected to be stable on Mars is within underground faults, fractures, and crevices. Here it likely occurs as brine or in the form of ice. Based on these conditions, a key to understanding the accumulation of large deposits of salt on both planets is linked to how brines behave in the subsurface when pressurized and heated beyond their supercritical point. At depths greater than about 3 km (P>300 bars) water will no longer boil in a steam phase. Rather, it becomes supercritical and will attain the phase of supercritical water vapor (SCRIW) with a specific gravity of typically 0.3 g/cm3. An important characteristic of SCRIW is its inability to dissolve the common sea salts. The salt dissolved in the brines will therefore precipitate as solid particles when brines (seawater on the Earth) move into the supercritical P&T-domain (T>400°C, P>300 bars). Numerical modeling of a hydrothermal system in the Atlantis II Deep of the Red Sea indicates that a

Salt Stability - The Effect of pHmax on Salt to Free Base Conversion.

PubMed

Hsieh, Yi-Ling; Merritt, Jeremy M; Yu, Weili; Taylor, Lynne S

2015-09-01

The aim of this study was to investigate how the disproportionation process can be impacted by the properties of the salt, specifically pHmax. Five miconazole salts and four sertraline salts were selected for this study. The extent of conversion was quantified using Raman spectroscopy. A mathematical model was utilized to estimate the theoretical amount of conversion. A trend was observed that for a given series of salts of a particular basic compound (both sertraline and miconazole are bases), the extent of disproportionation increases as pHmax decreases. Miconazole phosphate monohydrate and sertraline mesylate, although exhibiting significantly different pHmax values (more than 2 units apart), underwent a similar extent of disproportionation, which may be attributed to the lower buffering capacity of sertraline salts. This work shows that the disproportionation tendency can be influenced by pHmax and buffering capacity and thus highlights the importance of selecting the appropriate salt form during the screening process in order to avoid salt-to-free form conversion.

Ge14 Br8 (PEt3 )4 : A Subhalide Cluster of Germanium.

PubMed

Kunz, Tanja; Schrenk, Claudio; Schnepf, Andreas

2018-04-03

Heating a metastable solution of Ge I Br to room temperature led to the first structurally characterized metalloid subhalide cluster Ge 14 Br 8 (PEt 3 ) 4 (1). Furthermore 1 can be seen as the first isolated binary halide cluster on the way from Ge I Br to elemental germanium, giving insight into the complex reaction mechanism of its disproportionation reaction. Quantum chemical calculations further indicate that a classical bonding situation is realized within 1 and that the last step of the formation of 1 might include the trapping of GeBr 2 units. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The processing of enriched germanium for the Majorana Demonstrator and R&D for a next generation double-beta decay experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abgrall, N.; Arnquist, I. J.; Avignone III, F. T.

The Majorana Demonstrator is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluidsmore » from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.« less

The processing of enriched germanium for the Majorana Demonstrator and R&D for a next generation double-beta decay experiment

DOE PAGES

Abgrall, N.; Arnquist, I. J.; Avignone III, F. T.; ...

2017-10-07

The Majorana Demonstrator is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluidsmore » from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.« less

The processing of enriched germanium for the MAJORANA DEMONSTRATOR and R&D for a next generation double-beta decay experiment

NASA Astrophysics Data System (ADS)

Abgrall, N.; Arnquist, I. J.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Caja, J.; Caja, M.; Caldwell, T. S.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Dunagan, C.; Dunstan, D. T.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R. S.; Henning, R.; Hoppe, E. W.; Jasinski, B. R.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Lopez, A. M.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Meyer, J. H.; Myslik, J.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Reising, J. A.; Rielage, K.; Robertson, R. G. H.; Shanks, B.; Shirchenko, M.; Suriano, A. M.; Tedeschi, D.; Toth, L. M.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.; Zhu, B. X.

2018-01-01

The MAJORANA DEMONSTRATOR is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76 Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76 Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluids from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.

Broadband telecom to mid-infrared supercontinuum generation in a dispersion-engineered silicon germanium waveguide.

PubMed

Ettabib, Mohamed A; Xu, Lin; Bogris, Adonis; Kapsalis, Alexandros; Belal, Mohammad; Lorent, Emerick; Labeye, Pierre; Nicoletti, Sergio; Hammani, Kamal; Syvridis, Dimitris; Shepherd, David P; Price, Jonathan H V; Richardson, David J; Petropoulos, Periklis

2015-09-01

We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the -30  dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5-1.8 μm region and soliton fission. The SCG was modeled numerically, and excellent agreement with the experimental results was obtained.

Plasma 24,25-dihydroxyvitamin D concentration of Dahl salt-sensitive rats decreases during high salt intake

NASA Technical Reports Server (NTRS)

Thierry-Palmer, Myrtle; Tewolde, Teclemicael K.; Forte, Camille; Wang, Min; Bayorh, Mohamed A.; Emmett, Nerimiah L.; White, Jolanda; Griffin, Keri

2002-01-01

Dahl salt-sensitive rats, but not salt-resistant rats, develop hypertension in response to high salt intake. We have previously shown an inverse relationship between plasma 25-hydroxyvitamin D (25-OHD) concentration and blood pressure of Dahl salt-sensitive rats during high salt intake. In this study, we report on the relationship between high salt intake and plasma 24,25-dihydroxyvitamin D (24,25-(OH)(2)D) concentration of Dahl salt-sensitive and salt-resistant rats. Rats were fed a high salt diet (8%) and sacrificed at day 2, 7, 14, 21, and 28. Plasma 24,25-(OH)(2)D concentrations of salt-sensitive rats were reduced to 50% of that at baseline at day 2-when blood pressure and plasma 25-OHD concentration were unchanged, but 25-OHD content in the kidney was 81% of that at baseline. Plasma 24,25-(OH)(2)D concentration was reduced further to 10% of that at baseline from day 7 to 14 of high salt intake, a reduction that was prevented in rats switched to a low salt (0.3%) diet at day 7. Exogenous 24,25-dihydroxycholecalciferol (24,25-(OH)(2)D(3)), administered at a level that increased plasma 24,25-(OH)(2)D concentration to five times normal, did not attenuate the salt-induced hypertension of salt-sensitive rats. Plasma 24,25-(OH)(2)D concentration of salt-resistant rats was gradually reduced to 50% of that at baseline at day 14 and returned to baseline value at day 28 of high salt intake. We conclude that the decrease in plasma 24,25-(OH)(2)D concentration in salt-sensitive rats during high salt intake is caused by decreased 25-OHD content in the kidney and also by another unidentified mechanism.

Comparison of salt taste thresholds and salt usage behaviours between adults in Myanmar and Korea.

PubMed

Cho, Hyungjin; Kim, So Mi; Jeong, Seong Su; Kim, Soon Bae

2016-12-01

Excessive oral salt intake can induce hypertension. According to previous studies, the prevalence of hypertension is higher in Myanmar than in Korea. We postulated that Myanmar adults had higher salt taste thresholds and eat much saltier food. This study aimed to compare salt taste thresholds and salt usage behaviour scores between adults in Myanmar and Korea. This cross-sectional study enrolled patients who visited volunteer medical service clinics at Ansung in Korea and Hlegu and Bago in Myanmar in August 2014. We measured the vital signs, heights, and weights of each patient and evaluated detection thresholds, recognition thresholds, and salt preferences. All patients underwent urinalysis and spot urine Na tests. Additionally, they each completed a salt usage behaviour questionnaire. A total of 131 patients were enrolled, including 64 Myanmarese patients and 67 Korean patients. Blood pressure was significantly higher in the Myanmarese than in the Koreans. Detection and recognition thresholds, salt preferences, and spot urine sodium and salt usage behaviour scores were also higher in the Myanmarese than in the Korean subjects. We calculated correlation coefficients between systolic blood pressure and parameters that were related to salt intake. The detection and recognition thresholds were significantly correlated with systolic blood pressure. All parameters related to salt intake, including detection and recognition thresholds, salt preference, salt usage behaviour scores and spot urine sodium concentrations, are significantly higher in Myanmarese than in Korean individuals.

Electrodeposition of germanium from supercritical fluids.

PubMed

Ke, Jie; Bartlett, Philip N; Cook, David; Easun, Timothy L; George, Michael W; Levason, William; Reid, Gillian; Smith, David; Su, Wenta; Zhang, Wenjian

2012-01-28

Several Ge(II) and Ge(IV) compounds were investigated as possible reagents for the electrodeposition of Ge from liquid CH(3)CN and CH(2)F(2) and supercritical CO(2) containing as a co-solvent CH(3)CN (scCO(2)) and supercritical CH(2)F(2) (scCH(2)F(2)). For Ge(II) reagents the most promising results were obtained using [NBu(n)(4)][GeCl(3)]. However the reproducibility was poor and the reduction currents were significantly less than the estimated mass transport limited values. Deposition of Ge containing films was possible at high cathodic potential from [NBu(n)(4)][GeCl(3)] in liquid CH(3)CN and supercritical CO(2) containing CH(3)CN but in all cases they were heavily contaminated by C, O, F and Cl. Much more promising results were obtained using GeCl(4) in liquid CH(2)F(2) and supercritical CH(2)F(2). In this case the reduction currents were consistent with mass transport limited reduction and bulk electrodeposition produced amorphous films of Ge. Characterisation by XPS showed the presence of low levels of O, F and C, XPS confirmed the presence of Ge together with germanium oxides, and Raman spectroscopy showed that the as deposited amorphous Ge could be crystallised by the laser used in obtaining the Raman measurements.

The assembly of two isomorphous coordination compounds based on 1,4-cyclohexanedicarboxylic acid and 2,4-diamino-6-phenyl-1,3,5-triazine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xue-Fei; Wang, Xiao; Lun, Hui-Jie

The compounds [Co(e,a-cis-1,4-chdc)(phdat)]{sub n} (1) and [Cd(e,a-cis-1,4-chdc)(phdat)]{sub n} (2) have been synthesized under hydrothermal method by using 1,4-cyclohexanedicarboxylic acid (1,4-H{sub 2}chdc), 2,4-diamino-6-phenyl-1,3,5-triazine (phdat) as well as CoCl{sub 2}·6H{sub 2}O, CdCl{sub 2}·2.5H{sub 2}O respectively and characterized by IR spectra, X-ray single-crystal diffraction, powder X-ray single-crystal diffraction (PXRD), elemental analyses and thermogravimetric analyses (TGA). The results show the compounds 1 and 2 are isomorphous and exhibit paddle-wheel dinuclear Co{sub 2}(CO{sub 2}){sub 4}/Cd{sub 2}(CO{sub 2}){sub 4} units, which are further connected to 1D chain structures by μ{sub 4}:η{sup 1}:η{sup 1}:η{sup 1}:η{sup 1} 1,4-chdc{sup 2–} ligands and extended into a 3D structures via differentmore » hydrogen bonding and π…π stacking interactions. Furthermore, compound 1 exhibits antiferromagnetic behavior and compound 2 displays luminescent behavior at solid state. - Graphical abstract: Two isomorphous coordination compounds 1–2 have been synthesized and characterized by XRD, IR spectra and TGA etc. Compound 1 and 2 display antiferromagnetic behavior and luminescent behavior respectively. - Highlights: • Two novel polymers based on 1,4-cyclohexanedicarboxylic acid have been synthesized. • Compounds 1 and 2 feather 1D chain structure built up from paddle-wheel SBUs. • The magnetism of 2 is investigated. • The electrochemical property and luminescent property of 1 are investigated.« less

Mineral resource of the month: salt

USGS Publications Warehouse

Kostick, Dennis S.

2010-01-01

The article presents information on various types of salt. Rock salt is either found from underground halite deposits or near the surface. Other types of salt include solar salt, salt brine, and vacuum pan salt. The different uses of salt are also given including its use as a flavor enhancer, as a road deicing agent, and to manufacture sodium hydroxide.

Mechanical stratification of autochthonous salt: Implications from basin-scale numerical models of rifted margin salt tectonics

NASA Astrophysics Data System (ADS)

Ings, Steven; Albertz, Markus

2014-05-01

Deformation of salt and sediments owing to the flow of weak evaporites is a common phenomenon in sedimentary basins worldwide, and the resulting structures and thermal regimes have a significant impact on hydrocarbon exploration. Evaporite sequences ('salt') of significant thickness (e.g., >1km) are typically deposited in many cycles of seawater inundation and evaporation in restricted basins resulting in layered autochthonous evaporite packages. However, analogue and numerical models of salt tectonics typically treat salt as a homogeneous viscous material, often with properties of halite, the weakest evaporite. In this study, we present results of two-dimensional plane-strain numerical experiments designed to illustrate the effects of variable evaporite viscosity and embedded frictional-plastic ('brittle') sediment layers on the style of salt flow and associated deformation of the sedimentary overburden. Evaporite viscosity is a first-order control on salt flow rate and the style of overburden deformation. Near-complete evacuation of low-viscosity salt occurs beneath expulsion basins, whereas significant salt is trapped when viscosity is high. Embedded frictional-plastic sediment layers (with finite yield strength) partition salt flow and develop transient contractional structures (folds, thrust faults, and folded faults) in a seaward salt-squeeze flow regime. Multiple internal sediment layers reduce the overall seaward salt flow during sediment aggradation, leaving more salt behind to be re-mobilized during subsequent progradation. This produces more seaward extensive allochthonous salt sheets. If there is a density difference between the embedded layers and the surrounding salt, then the embedded layers 'fractionate' during deformation and either float to the surface or sink to the bottom (depending on density), creating a thick zone of pure halite. Such a process of 'buoyancy fractionation' may partially explain the apparent paradox of layered salt in

238Pu recovery and salt disposition from the molten salt oxidation process

NASA Astrophysics Data System (ADS)

Remerowski, M. L.; Stimmel, Jay J.; Wong, Amy S.; Ramsey, Kevin B.

2000-07-01

We have begun designing and optimizing our recovery and recycling processes by experimenting with samples of "spent salt" produced by MSO treatment of surrogate waste in the reaction vessel at the Naval Surface Warfare Center-Indian Head. One salt was produced by treating surrogate waste containing pyrolysis ash spiked with cerium. The other salt contains residues from MSO treatment of materials similar to those used in 238Pu processing, e.g., Tygon tubing, PVC bagout bags, HDPE bottles. Using these two salt samples, we will present results from our investigations.

High level active n+ doping of strained germanium through co-implantation and nanosecond pulsed laser melting

NASA Astrophysics Data System (ADS)

Pastor, David; Gandhi, Hemi H.; Monmeyran, Corentin P.; Akey, Austin J.; Milazzo, Ruggero; Cai, Yan; Napolitani, Enrico; Gwilliam, Russell M.; Crowe, Iain F.; Michel, Jurgen; Kimerling, L. C.; Agarwal, Anuradha; Mazur, Eric; Aziz, Michael J.

2018-04-01

Obtaining high level active n+ carrier concentrations in germanium (Ge) has been a significant challenge for further development of Ge devices. By ion implanting phosphorus (P) and fluorine (F) into Ge and restoring crystallinity using Nd:YAG nanosecond pulsed laser melting (PLM), we demonstrate 1020 cm-3 n+ carrier concentration in tensile-strained epitaxial germanium-on-silicon. Scanning electron microscopy shows that after laser treatment, samples implanted with P have an ablated surface, whereas P + F co-implanted samples have good crystallinity and a smooth surface topography. We characterize P and F concentration depth profiles using secondary ion mass spectrometry and spreading resistance profiling. The peak carrier concentration, 1020 cm-3 at 80 nm below the surface, coincides with the peak F concentration, illustrating the key role of F in increasing donor activation. Cross-sectional transmission electron microscopy of the co-implanted sample shows that the Ge epilayer region damaged during implantation is a single crystal after PLM. High-resolution X-ray diffraction and Raman spectroscopy measurements both indicate that the as-grown epitaxial layer strain is preserved after PLM. These results demonstrate that co-implantation and PLM can achieve the combination of n+ carrier concentration and strain in Ge epilayers necessary for next-generation, high-performance Ge-on-Si devices.

Self-assembly of tin wires via phase transformation of heteroepitaxial germanium-tin on germanium substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; Li, Lingzi; Yeo, Yee-Chia, E-mail: yeo@ieee.org

This work demonstrates and describes for the first time an unusual strain-relaxation mechanism by the formation and self-assembly of well-ordered tin wires during the thermal annealing of epitaxial Ge{sub 0.83}Sn{sub 0.17}-on-Ge(001) substrate. Fully strained germanium-tin alloys (Ge{sub 0.83}Sn{sub 0.17}) were epitaxially grown on Ge(001) substrate by molecular beam epitaxy. The morphological and compositional evolution of Ge{sub 0.83}Sn{sub 0.17} during thermal annealing is studied by atomic force microscopy, X-ray diffraction, transmission electron microscopy. Under certain annealing conditions, the Ge{sub 0.83}Sn{sub 0.17} layer decomposes into two stable phases, and well-defined Sn wires that are preferentially oriented along two orthogonal 〈100〉 azimuths aremore » formed. The formation of the Sn wires is related to the annealing temperature and the Ge{sub 0.83}Sn{sub 0.17} thickness, and can be explained by the nucleation of a grain with Sn islands on the outer front, followed by grain boundary migration. The Sn wire formation process is found to be thermally activated, and an activation enthalpy (E{sub c}) of 0.41 eV is extracted. This thermally activated phase transformation, i.e., 2D epitaxial layer to 3D wires, occurs via a mechanism akin to “cellular precipitation.” This synthesis route of Sn wires opens new possibilities for creation of nanoscale patterns at high-throughput without the need for lithography.« less

Salt Weathering on Mars

NASA Astrophysics Data System (ADS)

Jagoutz, E.

2006-12-01

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974

Should we eat less salt?

PubMed

Delahaye, François

2013-05-01

High blood pressure is a major cardiovascular risk factor. There is overwhelming evidence that high salt consumption is a major cause of increased blood pressure. There is also a link between high salt consumption and risk of stroke, left ventricular hypertrophy, renal disease, obesity, renal stones and stomach cancer. Reducing salt consumption leads to a decrease in blood pressure and the incidence of cardiovascular disease. There are no deleterious effects associated with reducing salt consumption and it is also very cost-effective. Many organizations and state governments have issued recommendations regarding the suitable amount of salt consumption. In France, the objective is a salt consumption<8g/day in men and<6.5g/day in women and children. As 80% of consumed salt comes from manufactured products in developed countries, reduction of salt consumption requires the participation of the food industry. The other tool is consumer information and education. Salt consumption has already decreased in France in recent years, but efforts must continue. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Correlation between optical properties and chemical composition of sputter-deposited germanium oxide (GeOx) films

NASA Astrophysics Data System (ADS)

Murphy, N. R.; Grant, J. T.; Sun, L.; Jones, J. G.; Jakubiak, R.; Shutthanandan, V.; Ramana, C. V.

2014-05-01

Germanium oxide (GeOx) films were grown on (1 0 0) Si substrates by reactive Direct-Current (DC) magnetron sputter-deposition using an elemental Ge target. The effects of oxygen gas fraction, Г = O2/(Ar + O2), on the deposition rate, structure, chemical composition and optical properties of GeOx films have been investigated. The chemistry of the films exhibits an evolution from pure Ge to mixed Ge + GeO + GeO2 and then finally to GeO2 upon increasing Г from 0.00 to 1.00. Grazing incidence X-ray analysis indicates that the GeOx films grown were amorphous. The optical properties probed by spectroscopic ellipsometry indicate that the effect of Г is significant on the optical constants of the GeOx films. The measured index of refraction (n) at a wavelength (λ) of 550 nm is 4.67 for films grown without any oxygen, indicating behavior characteristic of semiconducting Ge. The transition from germanium to mixed Ge + GeO + GeO2 composition is associated with a characteristic decrease in n (λ = 550 nm) to 2.62 and occurs at Г = 0.25. Finally n drops to 1.60 for Г = 0.50-1.00, where the films become GeO2. A detailed correlation between Г, n, k and stoichiometry in DC sputtered GeOx films is presented and discussed.

Actinide removal from spent salts

DOEpatents

Hsu, Peter C.; von Holtz, Erica H.; Hipple, David L.; Summers, Leslie J.; Adamson, Martyn G.

2002-01-01

A method for removing actinide contaminants (uranium and thorium) from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents are added to precipitate the thorium as thorium oxide and/or the uranium as either uranium oxide or as a diuranate salt. The precipitated materials are filtered, dried and packaged for disposal as radioactive waste. About 90% of the thorium and/or uranium present is removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 0.1 ppm of thorium or uranium.

Power plant I - Fused salt

NASA Astrophysics Data System (ADS)

Roche, M.

A solar thermal power plant using fused salt as the heat transfer fluid for steam power generation is analyzed for the feasibility of economic operation. The salt is also stored in a tank reservoir for maintaining the primary heat loop at temperatures high enough for the salts to remain liquid, and also to provide reserve power for the steam generator. Initial studies were with eutectic (hitec) salt comprising Na, KOH, and nitrites melting at 146 C, and further studies were performed employing draw salt, which has no nitrite, is more stable at high temperature, and melts at 225 C. The use of draw salt was found to allow a 5 percent reduction in storage capacity. Further examinations of the effects of the hitec salts on corrosion and composition degradation at high temperatures are indicated. The molten salt system is projected to offer an efficiency of 26 percent.

MONTHLY REPORT OF DEVELOPMENT, SEPTEMBER 1963

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1964-10-31

Methods for separating germanium from Taiga carbonaceous shale by flotation and salt roasting are described. The recovery of vanadium from Beaverlodge mill tailings by carbonate leaching is briefly discussed. Methods of chemical analysis are also discussed. (N.W.R.)

Radiation damage of the HEAO C-1 germanium detectors

NASA Technical Reports Server (NTRS)

Mahoney, W. A.; Ling, J. C.; Jacobson, A. S.

1981-01-01

The effects of radiation damage from proton bombardment of the four HEAO C-1 high purity germanium detectors have been measured and compared to predictions. Because of the presence of numerous gamma-ray lines in the detector background spectra and because of the relatively long exposure time of the HEAO 3 satellite to cosmic-ray and trapped protons, it has been possible to measure both the energy and time dependence of radiation damage. After 100 d in orbit, each of the four detectors has been exposed to approximately 3 x 10 to the 7th protons/sq cm, and the average energy resolution at 1460 keV had degraded from 3.2 keV fwhm to 8.6 keV fwhm. The lines were all broadened to the low energy side although the line profile was different for each of the four detectors. The damage-related contribution to the degradation in energy resolution was found to be linear in energy and proton influence.

Salt briquette: the form of salt monopoly in madura, 1883-1911

NASA Astrophysics Data System (ADS)

Wisnu; Alrianingrum, S.; Artono; Liana, C.

2018-01-01

This study describes the history of the salt monopoly in Indonesia because it is associated with the issue of salt crisis lately, widely reported in various media. This study tried to find answers to the relationship between monopoly and crisis events through the study of history. Monopoly policy by the government of the colonial period is actually an industrial modernization effort, but it turned out another impact. Although the colonial government wanted to issue a policy that ends strengthens the position of the government in the industry, but ultimately backfire and disasters in the salt industry at the time. This article discusses only the focus of the salt monopoly in Madura as a selection of events, arguing the island as a center of salt in Indonesia. The method used in this study using a review of history. Therefore, their explanations using historical sources. Methodologically through the process of collecting historical sources, criticize these sources, synthesize and interpret the analysis in an array of historical writing. In conclusion, although the salt monopoly policy gives a great advantage to the colonial government, but the overall population of Madura remains in a poor state. It is evident that the Madurese to migrate Madurese to various areas outside the island of Madura, to fix the economy.

Growth and characterization of ammonium nickel-cobalt sulfate Tutton's salt for UV light applications

NASA Astrophysics Data System (ADS)

Ghosh, Santunu; Oliveira, Michelle; Pacheco, Tiago S.; Perpétuo, Genivaldo J.; Franco, Carlos J.

2018-04-01

We have obtained a set of sample crystals of the family of Tutton's salt comprise in the isomorphic series with general chemical formula (NH4)2NixCo(1-x) (SO4)2·6H2O, by employing growth from solutions by slow evaporation technique. The samples crystals were characterized by ICP-AES, X-ray powder diffraction analysis, thermogravimetric analysis, UV-Vis-NIR, Raman and FTIR spectroscopy. This type of material has been studied because of its physical and chemical properties not yet understood and they have potential technological applications. Chemical analysis of the samples by ICP-AES method allowed us to investigate the efficiency of the method of growth used. Thermogravimetric analysis provides the information about the thermal stability of the obtained crystals for high temperature applications, and powder X-ray diffraction analysis at ambient and high temperature reveals the structural quality and structural change of the samples respectively. We have used Raman spectroscopy in the range 100-4000 cm-1 and FTIR spectroscopy in the range 400-4000 cm-1 to understand the internal vibrational mode of the octahedral complexes [Ni(H2O)6]2+ and [Co(H2O)6]2+, SO42- and NH4+ tetrahedra. The transmittance of our mixed ammonium nickel cobalt sulfate hexahydrate (ACNSH) crystals is 75% in the UV region, which indicates that they are ideal to use in UV light filters and UV sensors.

Atomic transport during solid-phase epitaxial recrystallization of amorphous germanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radek, M.; Bracht, H., E-mail: bracht@uni-muenster.de; Johnson, B. C.

2015-08-24

The atomic mixing of matrix atoms during solid-phase epitaxy (SPE) is studied by means of isotopically enriched germanium (Ge) multilayer structures that were amorphized by Ge ion implantation up to a depth of 1.5 μm. Recrystallization of the amorphous structure is performed at temperatures between 350 °C and 450 °C. Secondary-ion-mass-spectrometry is used to determine the concentration-depth profiles of the Ge isotope before and after SPE. An upper limit of 0.5 nm is deduced for the displacement length of the Ge matrix atoms by the SPE process. This small displacement length is consistent with theoretical models and atomistic simulations of SPE, indicating that themore » SPE mechanism consists of bond-switching with nearest-neighbours across the amorphous-crystalline (a/c) interface.« less

Dynamics of salt playa polygons

NASA Astrophysics Data System (ADS)

Goehring, L.; Fourrière, A.

2014-12-01

In natural salt playa or in evaporation pools for the salt extraction industry, one can sometimes see surprising regular structures formed by ridges of salt. These ridges connect together to form a self-organized network of polygons one to two meters in diameter, which we call salt polygons. Here we propose a mechanism based on porous media convection of salty water in soil to explain the formation and the scaling of the salt polygons. Surface evaporation causes a steady upward flow of salty water, which can cause precipitation near the surface. A vertical salt gradient then builds up in the porous soil, with heavy salt-saturated water lying over the less salty source water. This can drive convection when a threshold is reached, given by a critical Rayleigh number of about 7. We suggest that the salt polygons are the surface expression of the porous medium convection, with salt crystallizing along the positions of the convective downwellings. To study this instability directly, we developed a 2D analogue experiment using a Hele-Shaw cell filled with a porous medium saturated with a salt solution and heated from above. We perform a linear stability analysis of this system, and find that it is unstable to convection, with a most unstable wavelength that is set by a balance between salt diffusion and water evaporation. The Rayleigh number in our experiment is controlled by the particle size of our model soil, and the evaporation rate. We obtain results that scale with the observation of natural salt polygons. Using dye, we observe the convective movement of salty water and find downwelling convective plumes underneath the spots where surface salt ridges form, as shown in the attached figure.

Continued development of doped-germanium photoconductors for astronomical observations at wavelengths from 30 to 120 micrometers

NASA Technical Reports Server (NTRS)

Bratt, P. R.; Lewis, N. N.; Long, L. E.

1978-01-01

The development of doped-germanium detectors which have optimized performance in the 30- to 120-mu m wavelength range and are capable of achieving the objectives of the infrared astronomical satellite (IRAS) space mission is discussed. Topics covered include the growth and evaluation of Ge:Ga and Ge:Be crystals, procedures for the fabrication and testing of detectors, irradiance calculations, detector responsivity, and resistance measurements through MOSFET. Test data are presented in graphs and charts.

Salt and cocrystals of sildenafil with dicarboxylic acids: solubility and pharmacokinetic advantage of the glutarate salt.

PubMed

Sanphui, Palash; Tothadi, Srinu; Ganguly, Somnath; Desiraju, Gautam R

2013-12-02

Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H···O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.

Metals removal from spent salts

DOEpatents

Hsu, Peter C.; Von Holtz, Erica H.; Hipple, David L.; Summers, Leslie J.; Brummond, William A.; Adamson, Martyn G.

2002-01-01

A method and apparatus for removing metal contaminants from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents may be added to precipitate the metal oxide and/or the metal as either metal oxide, metal hydroxide, or as a salt. The precipitated materials are filtered, dried and packaged for disposal as waste or can be immobilized as ceramic pellets. More than about 90% of the metals and mineral residues (ashes) present are removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be spray-dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 1.0 ppm of contaminants.

Water and salt balance of Great Salt Lake, Utah, and simulation of water and salt movement through the causeway

USGS Publications Warehouse

Wold, Steven R.; Thomas, Blakemore E.; Waddell, Kidd M.

1997-01-01

The water and salt balance of Great Salt Lake primarily depends on the amount of inflow from tributary streams and the conveyance properties of a causeway constructed during 1957-59 that divides the lake into the south and north parts. The conveyance properties of the causeway originally included two culverts, each 15 feet wide, and the permeable rock-fill material.During 1980-86, the salt balance changed as a result of record high inflow that averaged 4,627,000 acre-feet annually and modifications made to the conveyance properties of the causeway that included opening a 300-foot-wide breach. In this study, a model developed in 1973 by Waddell and Bolke to simulate the water and salt balance of the lake was revised to accommodate the high water-surface altitude and modifications made to the causeway. This study, done by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of State Lands and Forestry, updates the model with monitoring data collected during 1980-86. This report describes the calibration of the model and presents the results of simulations for three hypothetical 10-year periods.During January 1, 1980, to July 31, 1984, a net load of 0.5 billion tons of dissolved salt flowed from the south to the north part of the lake primarily as a result of record inflows. From August 1, 1984, when the breach was opened, to December 31,1986, a net load of 0.3 billion tons of dissolved salt flowed from the north to the south part of the lake primarily as a result of the breach.For simulated inflow rates during a hypothetical 10-year period resulting in the water-surface altitude decreasing from about 4,200 to 4,192 feet, there was a net movement of about 1.0 billion tons of dissolved salt from the south to the north part, and about 1.7 billion tons of salt precipitated in the north part. For simulated inflow rates during a hypothetical 10-year period resulting in a rise in water-surface altitude from about 4,200 to 4

Salt Reductions in Some Foods in The Netherlands: Monitoring of Food Composition and Salt Intake

PubMed Central

Temme, Elisabeth H. M.; Hendriksen, Marieke A. H.; Milder, Ivon E. J.; Toxopeus, Ido B.; Westenbrink, Susanne; Brants, Henny A. M.; van der A, Daphne L.

2017-01-01

Background and objectives. High salt intake increases blood pressure and thereby the risk of chronic diseases. Food reformulation (or food product improvement) may lower the dietary intake of salt. This study describes the changes in salt contents of foods in the Dutch market over a five-year period (2011–2016) and differences in estimated salt intake over a 10-year period (2006–2015). Methods. To assess the salt contents of foods; we obtained recent data from chemical analyses and from food labels. Salt content of these foods in 2016 was compared to salt contents in the 2011 version Dutch Food Composition Database (NEVO, version 2011), and statistically tested with General Linear Models. To estimate the daily dietary salt intake in 2006, 2010, and 2015, men and women aged 19 to 70 years were recruited through random population sampling in Doetinchem, a small town located in a rural area in the eastern part of the Netherlands. The characteristics of the study population were in 2006: n = 317, mean age 49 years, 43% men, in 2010: n = 342, mean age 46 years, 45% men, and in 2015: n = 289, mean age 46 years, 47% men. Sodium and potassium excretion was measured in a single 24-h urine sample. All estimates were converted to a common metric: salt intake in grams per day by multiplication of sodium with a factor of 2.54. Results. In 2016 compared to 2011, the salt content in certain types of bread was on average 19 percent lower and certain types of sauce, soup, canned vegetables and legumes, and crisps had a 12 to 26 percent lower salt content. Salt content in other types of foods had not changed significantly. Between 2006, 2010 and 2015 the estimated salt intake among adults in Doetinchem remained unchanged. In 2015, the median estimated salt intake was 9.7 g per day for men and 7.4 g per day for women. As in 2006 and 2010, the estimated salt intake in 2015 exceeded the recommended maximum intake of 6 g per day set by the Dutch Health Council. Conclusion. In the

Salt Reductions in Some Foods in The Netherlands: Monitoring of Food Composition and Salt Intake.

PubMed

Temme, Elisabeth H M; Hendriksen, Marieke A H; Milder, Ivon E J; Toxopeus, Ido B; Westenbrink, Susanne; Brants, Henny A M; van der A, Daphne L

2017-07-22

High salt intake increases blood pressure and thereby the risk of chronic diseases. Food reformulation (or food product improvement) may lower the dietary intake of salt. This study describes the changes in salt contents of foods in the Dutch market over a five-year period (2011-2016) and differences in estimated salt intake over a 10-year period (2006-2015). To assess the salt contents of foods; we obtained recent data from chemical analyses and from food labels. Salt content of these foods in 2016 was compared to salt contents in the 2011 version Dutch Food Composition Database (NEVO, version 2011), and statistically tested with General Linear Models. To estimate the daily dietary salt intake in 2006, 2010, and 2015, men and women aged 19 to 70 years were recruited through random population sampling in Doetinchem, a small town located in a rural area in the eastern part of the Netherlands. The characteristics of the study population were in 2006: n = 317, mean age 49 years, 43% men, in 2010: n = 342, mean age 46 years, 45% men, and in 2015: n = 289, mean age 46 years, 47% men. Sodium and potassium excretion was measured in a single 24-h urine sample. All estimates were converted to a common metric: salt intake in grams per day by multiplication of sodium with a factor of 2.54. In 2016 compared to 2011, the salt content in certain types of bread was on average 19 percent lower and certain types of sauce, soup, canned vegetables and legumes, and crisps had a 12 to 26 percent lower salt content. Salt content in other types of foods had not changed significantly. Between 2006, 2010 and 2015 the estimated salt intake among adults in Doetinchem remained unchanged. In 2015, the median estimated salt intake was 9.7 g per day for men and 7.4 g per day for women. As in 2006 and 2010, the estimated salt intake in 2015 exceeded the recommended maximum intake of 6 g per day set by the Dutch Health Council. In the Netherlands, the salt content of bread, certain sauces, soups

Plant salt-tolerance mechanisms

DOE PAGES

Deinlein, Ulrich; Stephan, Aaron B.; Horie, Tomoaki; ...

2014-06-01

Crop performance is severely affected by high salt concentrations in soils. To engineer more salt-tolerant plants it is crucial to unravel the key components of the plant salt-tolerance network. Here we review our understanding of the core salt-tolerance mechanisms in plants. Recent studies have shown that stress sensing and signaling components can play important roles in regulating the plant salinity stress response. We also review key Na+ transport and detoxification pathways and the impact of epigenetic chromatin modifications on salinity tolerance. In addition, we discuss the progress that has been made towards engineering salt tolerance in crops, including marker-assisted selectionmore » and gene stacking techniques. We also identify key open questions that remain to be addressed in the future.« less

Early evolution of salt structures in north Louisiana salt basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobao, J.J.; Pilger, R.H. Jr.

1986-05-01

Several salt diapirs and pillows in southern and central north Louisiana have been studied using approximately 355 mi (570 km) of seismic reflection data and information from 57 deep well holes. Using seismic profiles with deep well-hole data is the most advantageous method to document regional salt tectonism through time. The following conclusions were reached on diapirism in the North Louisiana Salt basin. (1) The diapiric event began early (early Coahuilan) in the southern and central part of the basin, and later (late Coahuilan to Comanchean) in the northern part. (2) The initial diapiric event is much more abrupt andmore » intense in the southern and central diapirs when compared with the later diapiric event in the northern diapirs. (3) Regional depocenter shifting, relative sea level, local erosion with salt extrusion, and rapid depositional loading of sediments are the major controls on diapirism in the basin.« less

Salt weathering on Mars

NASA Astrophysics Data System (ADS)

Jagoutz, E.

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974

Combinations of fluorinated solvents with imide salts or methide salts for electrolytes

DOEpatents

Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Lei, Norman; Guerrero-Zavala, Guillermo; Kwong, Kristie W

2015-11-10

Provided are electrochemical cells and electrolytes used to build such cells. The electrolytes include imide salts and/or methide salts as well as fluorinated solvents capable of maintaining single phase solutions at between about -30.degree. C. to about 80.degree. C. The fluorinated solvents, such as fluorinated carbonates, fluorinated esters, and fluorinated esters, are less flammable than their non-fluorinated counterparts and improve safety characteristics of cells containing these solvents. The amount of fluorinated solvents in electrolytes may be between about 30% and 80% by weight not accounting weight of the salts. Linear and cyclic imide salts, such as LiN(SO.sub.2CF.sub.2CF.sub.3).sub.2, and LiN(SO.sub.2CF.sub.3).sub.2, as well as methide salts, such as LiC(SO.sub.2CF.sub.3).sub.3 and LiC(SO.sub.2CF.sub.2CF.sub.3).sub.3, may be used in these electrolytes. Fluorinated alkyl groups enhance solubility of these salts in the fluorinated solvents. In some embodiments, the electrolyte may also include a flame retardant, such as a phosphazene, and/or one or more ionic liquids.

Salt fluoridation and oral health.

PubMed

Marthaler, Thomas M

2013-11-01

The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the caries-protective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich, and several other cantons followed suit. Studies initiated in the early seventies showed that fluoride, when added to salt, inhibits dental caries. The addition of fluoride to salt for human consumption was officially authorized in 1980-82. In Switzerland 85% of domestic salt consumed is fluoridated and 67% in Germany. Salt fluoridation schemes are reaching more than one hundred million in Mexico, Colombia, Peru and Cuba. The cost of salt fluoridation is very low, within 0.02 and 0.05 € per year and capita. Children and adults of the low socio-economic strata tend to have substantially more untreated caries than higher strata. Salt fluoridation is by far the cheapest method for improving oral health. Salt fluoridation has cariostatic potential like water fluoridation (caries reductions up to 50%). In Europe, meaningful percentages of users have been attained only in Germany (67%) and Switzerland (85%). In Latin America, there are more than 100 million users, and several countries have arrived at coverage of 90 to 99%. Salt fluoridation is by far the cheapest method of caries prevention, and billions of people throughout the world could benefit from this method. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Physiological responses to salt stress of salt-adapted and directly salt (NaCl and NaCl+Na2SO4 mixture)-stressed cyanobacterium Anabaena fertilissima.

PubMed

Swapnil, Prashant; Rai, Ashwani K

2018-05-01

Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (Na 2 SO 4 ). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+Na 2 SO 4 mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly. Salinity impaired gross photosynthesis, electron transport activities, and respiration in parent cells, but not in the salt-adapted cells, except a marginal increase in PSI activity. Despite higher Na + concentration in the salt mixture, equimolar NaCl appeared more inhibitive to growth. Sucrose and trehalose content and antioxidant activities were maximal in 250 mM NaCl-treated cells, followed by salt mixture and was almost identical in salt-adapted (exposed to 500 mm NaCl) and control cells, except a marginal increase in ascorbate peroxidase activity and an additional fourth superoxide dismutase isoform. Catalase isoform of 63 kDa was induced only in salt-stressed cells. Salinity increased the uptake of intracellular Na + and Ca 2+ and leakage of K + in parent cells, while cation level in salt-adapted cells was comparable to control. Though there was differential increase in intracellular Ca 2+ under different salt treatments, ratio of Ca 2+ /Na + remained the same. It is inferred that stepwise increment in the salt concentration enabled the cyanobacterium to undergo priming effect and acquire robust and efficient defense system involving the least energy.

Electrolyte salts for nonaqueous electrolytes

DOEpatents

Amine, Khalil; Zhang, Zhengcheng; Chen, Zonghai

2012-10-09

Metal complex salts may be used in lithium ion batteries. Such metal complex salts not only perform as an electrolyte salt in a lithium ion batteries with high solubility and conductivity, but also can act as redox shuttles that provide overcharge protection of individual cells in a battery pack and/or as electrolyte additives to provide other mechanisms to provide overcharge protection to lithium ion batteries. The metal complex salts have at least one aromatic ring. The aromatic moiety may be reversibly oxidized/reduced at a potential slightly higher than the working potential of the positive electrode in the lithium ion battery. The metal complex salts may also be known as overcharge protection salts.

ADR salt pill design and crystal growth process for hydrated magnetic salts

NASA Technical Reports Server (NTRS)

Shirron, Peter J. (Inventor); DiPirro, Michael J. (Inventor); Canavan, Edgar R. (Inventor)

2013-01-01

A process is provided for producing a salt pill for use in very low temperature adiabatic demagnetization refrigerators (ADRs). The method can include providing a thermal bus in a housing. The thermal bus can include an array of thermally conductive metal conductors. A hydrated salt can be grown on the array of thermally conductive metal conductors. Thermal conductance can be provided to the hydrated salt.

Reconsolidated Salt as a Geotechnical Barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Francis D.; Gadbury, Casey

Salt as a geologic medium has several attributes favorable to long-term isolation of waste placed in mined openings. Salt formations are largely impermeable and induced fractures heal as stress returns to equilibrium. Permanent isolation also depends upon the ability to construct geotechnical barriers that achieve nearly the same high-performance characteristics attributed to the native salt formation. Salt repository seal concepts often include elements of reconstituted granular salt. As a specific case in point, the Waste Isolation Pilot Plant recently received regulatory approval to change the disposal panel closure design from an engineered barrier constructed of a salt-based concrete to onemore » that employs simple run-of-mine salt and temporary bulkheads for isolation from ventilation. The Waste Isolation Pilot Plant is a radioactive waste disposal repository for defense-related transuranic elements mined from the Permian evaporite salt beds in southeast New Mexico. Its approved shaft seal design incorporates barrier components comprising salt-based concrete, bentonite, and substantial depths of crushed salt compacted to enhance reconsolidation. This paper will focus on crushed salt behavior when applied as drift closures to isolate disposal rooms during operations. Scientific aspects of salt reconsolidation have been studied extensively. The technical basis for geotechnical barrier performance has been strengthened by recent experimental findings and analogue comparisons. The panel closure change was accompanied by recognition that granular salt will return to a physical state similar to the halite surrounding it. Use of run-of-mine salt ensures physical and chemical compatibility with the repository environment and simplifies ongoing disposal operations. Our current knowledge and expected outcome of research can be assimilated with lessons learned to put forward designs and operational concepts for the next generation of salt repositories. Mined salt

Pathophysiology of salt sensitivity hypertension.

PubMed

Ando, Katsuyuki; Fujita, Toshiro

2012-06-01

Dietary salt intake is the most important factor contributing to hypertension, but the salt susceptibility of blood pressure (BP) is different in individual subjects. Although the pathogenesis of salt-sensitive hypertension is heterogeneous, it is mainly attributable to an impaired renal capacity to excrete sodium (Na(+) ). We recently identified two novel mechanisms that impair renal Na(+) -excreting function and result in an increase in BP. First, mineralocorticoid receptor (MR) activation in the kidney, which facilitates distal Na(+) reabsorption through epithelial Na(+) channel activation, causes salt-sensitive hypertension. This mechanism exists not only in models of high-aldosterone hypertension as seen in conditions of obesity or metabolic syndrome, but also in normal- or low-aldosterone type of salt-sensitive hypertension. In the latter, Rac1 activation by salt excess causes MR stimulation. Second, renospecific sympathoactivation may cause an increase in BP under conditions of salt excess. Renal beta2 adrenoceptor stimulation in the kidney leads to decreased transcription of the gene encoding WNK4, a negative regulator of Na(+) reabsorption through Na(+) -Cl (-) cotransporter in the distal convoluted tubules, resulting in salt-dependent hypertension. Abnormalities identified in these two pathways of Na(+) reabsorption in the distal nephron may present therapeutic targets for the treatment of salt-sensitive hypertension.

Microbial Successions and Metabolite Changes during Fermentation of Salted Shrimp (Saeu-Jeot) with Different Salt Concentrations

PubMed Central

Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok

2014-01-01

To investigate the effects of salt concentration on saeu-jeot (salted shrimp) fermentation, four sets of saeu-jeot samples with 20%, 24%, 28%, and 32% salt concentrations were prepared, and the pH, bacterial and archaeal abundances, bacterial communities, and metabolites were monitored during the entire fermentation period. Quantitative PCR showed that Bacteria were much more abundant than Archaea in all saeu-jeot samples, suggesting that bacterial populations play more important roles than archaeal populations even in highly salted samples. Community analysis indicated that Vibrio, Photobacterium, Psychrobacter, Pseudoalteromonas, and Enterovibrio were identified as the initially dominant genera, and the bacterial successions were significantly different depending on the salt concentration. During the early fermentation period, Salinivibrio predominated in the 20% salted samples, whereas Staphylococcus, Halomonas, and Salimicrobium predominated in the 24% salted samples; eventually, Halanaerobium predominated in the 20% and 24% salted samples. The initially dominant genera gradually decreased as the fermentation progressed in the 28% and 32% salted samples, and eventually Salimicrobium became predominant in the 28% salted samples. However, the initially dominant genera still remained until the end of fermentation in the 32% salted samples. Metabolite analysis showed that the amino acid profile and the initial glycerol increase were similar in all saeu-jeot samples regardless of the salt concentration. After 30–80 days of fermentation, the levels of acetate, butyrate, and methylamines in the 20% and 24% salted samples increased with the growth of Halanaerobium, even though the amino acid concentrations steadily increased until approximately 80–107 days of fermentation. This study suggests that a range of 24–28% salt concentration in saeu-jeot fermentation is appropriate for the production of safe and tasty saeu-jeot. PMID:24587230

Maximizing Tensile Strain in Germanium Nanomembranes for Enhanced Optoelectronic Properties

NASA Astrophysics Data System (ADS)

Sanchez Perez, Jose Roberto

Silicon, germanium, and their alloys, which provide the leading materials platform of microelectronics, are extremely inefficient light emitters because of their indirect fundamental energy band gap. This basic materials property has so far hindered the development of group-IV photonic-active devices, including light emitters and diode lasers, thereby significantly limiting our ability to integrate electronic and photonic functionalities at the chip level. Theoretical studies have predicted that tensile strain in Ge lowers the direct energy band gap relative to the indirect one, and that, with sufficient strain, Ge becomes direct-band gap, thus enabling facile interband light emission and the fabrication of Group IV lasers. It has, however, not been possible to impart sufficient strain to Ge to reach the direct-band gap goal, because bulk Ge fractures at much lower strains. Here it is shown that very thin sheets of Ge(001), called nanomembranes (NMs), can be used to overcome this materials limitation. Germanium nanomembranes (NMs) in the range of thicknesses from 20nm to 100nm were fabricated and then transferred and mounted to a flexible substrate [a polyimide (PI) sheet]. An apparatus was developed to stress the PI/NM combination and provide for in-situ Raman measurements of the strain as a function of applied stress. This arrangement allowed for the introduction of sufficient biaxial tensile strain (>1.7%) to transform Ge to a direct-band gap material, as determined by photoluminescence (PL) measurements and theory. Appropriate shifts in the emission spectrum and increases in PL intensities were observed. The advance in this work was nanomembrane fabrication technology; i.e., making thin enough Ge sheets to accept sufficiently high levels of strain without fracture. It was of interest to determine if the strain at which fracture ultimately does occur can be raised, by evaluating factors that initiate fracture. Attempts to assess the effect of free edges (enchant

Kinematics and dynamics of salt movement driven by sub-salt normal faulting and supra-salt sediment accumulation - combined analogue experiments and analytical calculations

NASA Astrophysics Data System (ADS)

Warsitzka, Michael; Kukowski, Nina; Kley, Jonas

2017-04-01

In extensional sedimentary basins, the movement of ductile salt is mainly controlled by the vertical displacement of the salt layer, differential loading due to syn-kinematic deposition, and tectonic shearing at the top and the base of the salt layer. During basement normal faulting, salt either tends to flow downward to the basin centre driven by its own weight or it is squeezed upward due to differential loading. In analogue experiments and analytical models, we address the interplay between normal faulting of the sub-salt basement, compaction and density inversion of the supra-salt cover and the kinematic response of the ductile salt layer. The analogue experiments consist of a ductile substratum (silicone putty) beneath a denser cover layer (sand mixture). Both layers are displaced by normal faults mimicked through a downward moving block within the rigid base of the experimental apparatus and the resulting flow patterns in the ductile layer are monitored and analysed. In the computational models using an analytical approximative solution of the Navier-Stokes equation, the steady-state flow velocity in an idealized natural salt layer is calculated in order to evaluate how flow patterns observed in the analogue experiments can be translated to nature. The analytical calculations provide estimations of the prevailing direction and velocity of salt flow above a sub-salt normal fault. The results of both modelling approaches show that under most geological conditions salt moves downwards to the hanging wall side as long as vertical offset and compaction of the cover layer are small. As soon as an effective average density of the cover is exceeded, the direction of the flow velocity reverses and the viscous material is squeezed towards the elevated footwall side. The analytical models reveal that upward flow occurs even if the average density of the overburden does not exceed the density of salt. By testing various scenarios with different layer thicknesses

Measuring salt retention.

DOT National Transportation Integrated Search

2013-03-01

This research developed and completed a field evaluation of salt distribution equipment. The evaluation provides a direct comparison of three different types of salt spreaders at three different truck speeds and brine rates. A rubber mat was divided ...

Impact of negative capacitance effect on Germanium Double Gate pFET for enhanced immunity to interface trap charges

NASA Astrophysics Data System (ADS)

Bansal, Monika; Kaur, Harsupreet

2018-05-01

In this work, a comprehensive drain current model has been developed for long channel Negative Capacitance Germanium Double Gate p-type Field Effect Transistor (NCGe-DG-pFET) by using 1-D Poisson's equation and Landau-Khalatnikov equation. The model takes into account interface trap charges and by using the derived model various parameters such as surface potential, gain, gate capacitance, subthreshold swing, drain current, transconductance, output conductance and Ion/Ioff ratio have been obtained and it is demonstrated that by incorporating ferroelectric material as gate insulator with Ge-channel, subthreshold swing values less than 60 mV/dec can be achieved along with improved gate controllability and current drivability. Further, to critically analyze the advantages offered by NCGe-DG-pFET, a detailed comparison has been done with Germanium Double Gate p-type Field Effect Transistor (Ge-DG-pFET) and it is shown that NCGe-DG-pFET exhibits high gain, enhanced transport efficiency in channel, very less or negligible degradation in device characteristics due to interface trap charges as compared to Ge-DG-pFET. The analytical results so obtained show good agreement with simulated results obtained from Silvaco ATLAS TCAD tool.

Silicon-Germanium Films Grown on Sapphire for Ka-Band Communications Applications

NASA Technical Reports Server (NTRS)

Alterovitz, Samuel A.; Mueller, Carl H.; Croke, Edward T.

2004-01-01

NASA's vision in the space communications area is to develop a broadband data network in which there is a high degree of interconnectivity among the various satellite systems, ground stations, and wired systems. To accomplish this goal, we will need complex electronic circuits integrating analog and digital data handling at the Ka-band (26 to 40 GHz). The purpose of this project is to show the feasibility of a new technology for Ka-band communications applications, namely silicon germanium (SiGe) on sapphire. This new technology will have several advantages in comparison to the existing silicon-substrate- based circuits. The main advantages are extremely low parasitic reactances that enable much higher quality active and passive components, better device isolation, higher radiation tolerance, and the integration of digital and analog circuitry on a single chip.

Fetal bile salt metabolism

PubMed Central

Smallwood, R. A.; Lester, R.; Piasecki, G. J.; Klein, P. D.; Greco, R.; Jackson, B. T.

1972-01-01

Bile salt metabolism was studied in fetal dogs 1 wk before term. The size and distribution of the fetal bile salt pool were measured, and individual bile salts were identified. The hepatic excretion of endogenous bile salts was studied in bile fistula fetuses, and the capacity of this excretory mechanism was investigated by the i.v. infusion of a load of sodium taurocholate-14C up to 20 times the endogenous pool size. The total fetal bile salt pool was 30.9±2.7 μmoles, of which two-thirds was in the fetal gallbladder. Expressed on a body weight basis, this was equal to approximately one-half the estimated pool size in the adult dog (119.2±11.3 vs. 247.5±33.1 μmoles/kg body wt). Measurable quantities of bile salt were found in small bowel (6.0±1.8 μmoles), large bowel (1.1±0.3 μmoles), liver (1.2±0.5 μmoles), and plasma (0.1±0.03 μmoles). Plasma bile salt levels were significantly greater in fetal than in maternal plasma (1.01±0.24 μg/ml vs. 0.36±0.06 μg/ml; P < 0.05). Fetal hepatic bile salt excretion showed a fall over the period of study from 2.04±0.34 to 0.30±0.07 μmoles/hr. The maximal endogenous bile salt concentration in fetal hepatic bile was 18.7±1.5 μmoles/ml. The concentration in fetal gallbladder bile was 73.9±8.6 μmoles/ml; and, in those studies in which hepatic and gallbladder bile could be compared directly, the gallbladder appeared to concentrate bile four- to fivefold. Taurocholate, taurochenodeoxycholate, and taurodeoxycholate were present in fetal bile, but no free bile salts were identified. The presence of deoxycholate was confirmed by thin-layer chromatography and gas liquid chromatography, and the absence of microorganisms in fetal gut suggests that it was probably transferred from the maternal circulation. After infusion of a taurocholate load, fetal hepatic bile salt excretion increased 30-fold, so that 85-95% of the dose was excreted by the fetal liver during the period of observation. Placental transfer accounted

Rheological stratification of the Hormuz Salt Formation in Iran - microstructural study of the dirty and pure rock salts from the Kuh-e-Namak (Dashti) salt diapir

NASA Astrophysics Data System (ADS)

Závada, Prokop; Desbois, Guillaume; Urai, Janos; Schulmann, Karel; Rahmati, Mahmoud; Lexa, Ondrej; Wollenberg, Uwe

2014-05-01

Significant viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' terrestrial debris bearing rock salt types and 'strong' pure rock salt types are questioned for deformation mechanisms using detailed quantitative microstructural study including crystallographic preferred orientation (CPO) mapping of halite grains. While the solid impurity rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts (debris free) reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although flow in both, the recrystallized dirty and clean salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS) and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts are explained by significantly slower rates of intergranular diffusion and piling up of dislocations at hematite inclusions in clean salt types. Porphyroclasts of clean salts deform by semi-brittle and plastic mechanisms with intra-crystalline damage being induced also by fluid inclusions that explode in the crystals at high fluid pressures. Boudins of clean salt types with coarse grained and original sedimentary microstructure suggest that clean rock salts are associated with dislocation creep dominated power law flow in the source layer and the diapiric stem. Rheological contrasts between both rock salt classes apply in general for the variegated and terrestrial debris rich ("dirty") Lower Hormuz and the "clean" rock salt forming the Upper Hormuz, respectively, and suggest that large strain rate gradients likely exist along horizons of mobilized salt types of different composition and microstructure.

Dosimetry using silver salts

DOEpatents

Warner, Benjamin P.

2003-06-24

The present invention provides a method for detecting ionizing radiation. Exposure of silver salt AgX to ionizing radiation results in the partial reduction of the salt to a mixture of silver salt and silver metal. The mixture is further reduced by a reducing agent, which causes the production of acid (HX) and the oxidized form of the reducing agent (R). Detection of HX indicates that the silver salt has been exposed to ionizing radiation. The oxidized form of the reducing agent (R) may also be detected. The invention also includes dosimeters employing the above method for detecting ionizing radiation.

Determination of discretionary salt intake in rural Guatemala and Benin to determine the iodine fortification of salt required to control iodine deficiency disorders: studies using lithium-labeled salt.

PubMed

Melse-Boonstra, A; Rozendaal, M; Rexwinkel, H; Gerichhausen, M J; van den Briel, T; Bulux, J; Solomons, N W; West, C E

1998-09-01

The use of discretionary salt, which is salt added during cooking and at the table, as a suitable vehicle for iodine intake was assessed by measuring salt consumption using the lithium-marker technique in rural areas of Guatemala and Benin. In both countries, we studied boys aged 6-12 y and their mothers. Subjects used lithium-labeled salt after all unlabeled salt was removed from their households. In Guatemala, 24-h urine samples for 9 mother-son pairs were collected at baseline and on days 7, 8, and 9 during the use of lithium-labeled salt. Total maternal salt intake averaged 5.2 +/- 1.7 g/d (mean +/- SD), of which 77 +/- 24% came from discretionary sources, whereas Guatemalan boys consumed 1.8 +/- 0.6 g salt/d, of which 72 +/- 12% came from discretionary sources. In Benin, urine collection from 13 mother-son pairs took place at baseline and on days 5 and 7. Beninese mothers had a total salt intake of 9.0 +/- 2.9 g/d and their sons had an intake of 5.7 +/- 2.8 g/d; discretionary salt contributed 52 +/- 14% and 50 +/- 13%, respectively, of total salt consumed. Therefore, fortification of household salt appears to be an appropriate method of controlling iodine deficiency in both countries, although fortification of other salt sources could be considered in Benin.

Effects of trap-assisted tunneling on gate-induced drain leakage in silicon-germanium channel p-type FET for scaled supply voltages

NASA Astrophysics Data System (ADS)

Tiwari, Vishal A.; Divakaruni, Rama; Hook, Terence B.; Nair, Deleep R.

2016-04-01

Silicon-germanium is considered as an alternative channel material to silicon p-type FET (pFET) for the development of energy efficient high performance transistors for 28 nm and beyond in a high-k metal gate technology because of its lower threshold voltage and higher mobility. However, gate-induced drain leakage (GIDL) is a concern for high threshold voltage device design because of tunneling at reduced bandgap. In this work, the trap-assisted tunneling and band-to-band tunneling (BTBT) effects on GIDL is analyzed and modeled for SiGe pFETs. Experimental results and Monte Carlo simulation results reveal that the pre-halo germanium pre-amorphization implant used to contain the short channel effects contribute to GIDL at the drain sidewall in addition to GIDL due to BTBT in SiGe devices. The results are validated by comparing the experimental observations with the numerical simulation and a set of calibrated models are used to describe the GIDL mechanisms for various drain and gate bias.

Dietary Salt Intake and Hypertension

PubMed Central

2014-01-01

Over the past century, salt has been the subject of intense scientific research related to blood pressure elevation and cardiovascular mortalities. Moderate reduction of dietary salt intake is generally an effective measure to reduce blood pressure. However, recently some in the academic society and lay media dispute the benefits of salt restriction, pointing to inconsistent outcomes noted in some observational studies. A reduction in dietary salt from the current intake of 9-12 g/day to the recommended level of less than 5-6 g/day will have major beneficial effects on cardiovascular health along with major healthcare cost savings around the world. The World Health Organization (WHO) strongly recommended to reduce dietary salt intake as one of the top priority actions to tackle the global non-communicable disease crisis and has urged member nations to take action to reduce population wide dietary salt intake to decrease the number of deaths from hypertension, cardiovascular disease and stroke. However, some scientists still advocate the possibility of increased risk of CVD morbidity and mortality at extremes of low salt intake. Future research may inform the optimal sodium reduction strategies and intake targets for general populations. Until then, we have to continue to build consensus around the greatest benefits of salt reduction for CVD prevention, and dietary salt intake reduction strategies must remain at the top of the public health agenda. PMID:25061468

Salt-Stress Response Mechanisms Using de Novo Transcriptome Sequencing of Salt-Tolerant and Sensitive Corchorus spp. Genotypes

PubMed Central

Yang, Zemao; Lu, Ruike; Dai, Zhigang; Yan, An; Tang, Qing; Cheng, Chaohua; Xu, Ying; Yang, Wenting; Su, Jianguang

2017-01-01

High salinity is a major environmental stressor for crops. To understand the regulatory mechanisms underlying salt tolerance, we conducted a comparative transcriptome analysis between salt-tolerant and salt-sensitive jute (Corchorus spp.) genotypes in leaf and root tissues under salt stress and control conditions. In total, 68,961 unigenes were identified. Additionally, 11,100 unigenes (including 385 transcription factors (TFs)) exhibited significant differential expression in salt-tolerant or salt-sensitive genotypes. Numerous common and unique differentially expressed unigenes (DEGs) between the two genotypes were discovered. Fewer DEGs were observed in salt-tolerant jute genotypes whether in root or leaf tissues. These DEGs were involved in various pathways, such as ABA signaling, amino acid metabolism, etc. Among the enriched pathways, plant hormone signal transduction (ko04075) and cysteine/methionine metabolism (ko00270) were the most notable. Eight common DEGs across both tissues and genotypes with similar expression profiles were part of the PYL-ABA-PP2C (pyrabactin resistant-like/regulatory components of ABA receptors-abscisic acid-protein phosphatase 2C). The methionine metabolism pathway was only enriched in salt-tolerant jute root tissue. Twenty-three DEGs were involved in methionine metabolism. Overall, numerous common and unique salt-stress response DEGs and pathways between salt-tolerant and salt-sensitive jute have been discovered, which will provide valuable information regarding salt-stress response mechanisms and help improve salt-resistance molecular breeding in jute. PMID:28927022

Germanium Isotopes - the Global Budget and Paleoceanographic Potential

NASA Astrophysics Data System (ADS)

Baronas, J. J.; Hammond, D. E.; Rouxel, O. J.

2017-12-01

The distribution of element isotope ratios in rocks, sediments, rivers, and seawater can provide key insights about the operation and coupling of various biogeochemical cycles that are directly or indirectly responsible for the climate and habitability of the Earth surface environment. Germanium (Ge) is a trace element that shares many chemical similarities with silicon (Si), in addition to some siderophilic, chalcophilic, and organophilic properties. As a result, Ge stable isotope ratios (δ74Ge) and Ge/Si ratios can be used to trace various biogeochemical processes. These include silicate rock weathering, which modulates atmospheric pCO2 and supplies nutrients to ecosystems, biogenic silica formation, which is coupled to ocean productivity, and marine sediment diagenesis, which ultimately controls the removal of material from the Earth's surface. I will present an overview of my dissertation research concerning the global Ge isotope cycle, with insights into Ge isotope fractionation during secondary mineral precipitation during weathering on continents and during authigenesis in marine sediments. I will also discuss the potential for the δ74Ge sedimentary record to be used as a paleoceanographic proxy, given the constraints on the global Ge isotope budget.

The variability of reported salt levels in fast foods across six countries: opportunities for salt reduction.

PubMed

Dunford, Elizabeth; Webster, Jacqueline; Woodward, Mark; Czernichow, Sebastien; Yuan, Wen Lun; Jenner, Katharine; Ni Mhurchu, Cliona; Jacobson, Michael; Campbell, Norm; Neal, Bruce

2012-06-12

Several fast food companies have made commitments to reduce the levels of salt in the foods they serve, but technical issues are often cited as a barrier to achieving substantial reductions. Our objective was to examine the reported salt levels for products offered by leading multinational fast food chains. Data on salt content for products served by six fast food chains operating in Australia, Canada, France, New Zealand, the United Kingdom and the United States were collected by survey in April 2010. Mean salt contents (and their ranges) were calculated and compared within and between countries and companies. We saw substantial variation in the mean salt content for different categories of products. For example, the salads we included in our survey contained 0.5 g of salt per 100 g, whereas the chicken products we included contained 1.6 g. We also saw variability between countries: chicken products from the UK contained 1.1 g of salt per 100 g, whereas chicken products from the US contained 1.8 g. Furthermore, the mean salt content of food categories varied between companies and between the same products in different countries (e.g., McDonald's Chicken McNuggets contain 0.6 g of salt per 100 g in the UK, but 1.6 g of salt per 100 g in the US). The salt content of fast foods varies substantially, not only by type of food, but by company and country in which the food is produced. Although the reasons for this variation are not clear, the marked differences in salt content of very similar products suggest that technical reasons are not a primary explanation. In the right regulatory environment, it is likely that fast food companies could substantially reduce the salt in their products, translating to large gains for population health.

The variability of reported salt levels in fast foods across six countries: opportunities for salt reduction

PubMed Central

Dunford, Elizabeth; Webster, Jacqueline; Woodward, Mark; Czernichow, Sebastien; Yuan, Wen Lun; Jenner, Katharine; Mhurchu, Cliona Ni; Jacobson, Michael; Campbell, Norm; Neal, Bruce

2012-01-01

Background: Several fast food companies have made commitments to reduce the levels of salt in the foods they serve, but technical issues are often cited as a barrier to achieving substantial reductions. Our objective was to examine the reported salt levels for products offered by leading multinational fast food chains. Methods: Data on salt content for products served by six fast food chains operating in Australia, Canada, France, New Zealand, the United Kingdom and the United States were collected by survey in April 2010. Mean salt contents (and their ranges) were calculated and compared within and between countries and companies. Results: We saw substantial variation in the mean salt content for different categories of products. For example, the salads we included in our survey contained 0.5 g of salt per 100 g, whereas the chicken products we included contained 1.6 g. We also saw variability between countries: chicken products from the UK contained 1.1 g of salt per 100 g, whereas chicken products from the US contained 1.8 g. Furthermore, the mean salt content of food categories varied between companies and between the same products in different countries (e.g., McDonald’s Chicken McNuggets contain 0.6 g of salt per 100 g in the UK, but 1.6 g of salt per 100 g in the US). Interpretation: The salt content of fast foods varies substantially, not only by type of food, but by company and country in which the food is produced. Although the reasons for this variation are not clear, the marked differences in salt content of very similar products suggest that technical reasons are not a primary explanation. In the right regulatory environment, it is likely that fast food companies could substantially reduce the salt in their products, translating to large gains for population health. PMID:22508978

Alternative methods of salt disposal at the seven salt sites for a nuclear waste repository

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-02-01

This study discusses the various alternative salt management techniques for the disposal of excess mined salt at seven potentially acceptable nuclear waste repository sites: Deaf Smith and Swisher Counties, Texas; Richton and Cypress Creek Domes, Mississippi; Vacherie Dome, Louisiana; and Davis and Lavender Canyons, Utah. Because the repository development involves the underground excavation of corridors and waste emplacement rooms, in either bedded or domed salt formations, excess salt will be mined and must be disposed of offsite. The salt disposal alternatives examined for all the sites include commercial use, ocean disposal, deep well injection, landfill disposal, and underground mine disposal.more » These alternatives (and other site-specific disposal methods) are reviewed, using estimated amounts of excavated, backfilled, and excess salt. Methods of transporting the excess salt are discussed, along with possible impacts of each disposal method and potential regulatory requirements. A preferred method of disposal is recommended for each potentially acceptable repository site. 14 refs., 5 tabs.« less

Influence of the deposition and annealing temperatures on the luminescence of germanium nanocrystals formed in GeO x films and multilayer Ge/SiO2 structures

NASA Astrophysics Data System (ADS)

Grachev, D. A.; Ershov, A. V.; Karabanova, I. A.; Pirogov, A. V.; Nezhdanov, A. V.; Mashin, A. I.; Pavlov, D. A.

2017-05-01

The GeO x films and multilayer nanoperiodic Ge/SiO2 structures containing germanium nanocrystals were prepared by physical vapor deposition in vacuum. The properties of the films and multilayer structures were controlled by varying the deposition temperature in the range of 35-590°C and the annealing temperature in the range of 400-1000°C. A comparative study of the optical and structural characteristics of the nanosystems was performed using the methods of Raman scattering spectroscopy, IR spectroscopy, photoluminescence, and electron microscopy, which demonstrated a qualitative similarity of the nanosystems. It was found that annealing at temperatures in the range of 600-800°C leads to the formation of germanium nanocrystals with a high density ( 1012 cm-2), whereas in the materials not subjected to annealing, their density did not exceed 1010 cm-2. The average size of the nanocrystals was found to be 5 ± 2 nm. For both nanosystems, three luminescence bands were observed at 1.2, 1.5-1.7, and 1.7-2.0 eV. It was assumed that the origin of these bands is associated with germanium nanocrystals, oxygen-deficient centers in GeOx, and defects at the Ge/dielectric interface, respectively.

Significance of adjusting salt intake by body weight in the evaluation of dietary salt and blood pressure.

PubMed

Hashimoto, Tomomi; Takase, Hiroyuki; Okado, Tateo; Sugiura, Tomonori; Yamashita, Sumiyo; Kimura, Genjiro; Ohte, Nobuyuki; Dohi, Yasuaki

2016-08-01

The close association between dietary salt and hypertension is well established. However, previous studies generally assessed salt intake without adjustment for body weight. Herein, we investigated the significance of body weight-adjusted salt intake in the general population. The present cross-sectional study included 7629 participants from our yearly physical checkup program, and their salt intake was assessed using a spot urine test to estimate 24-hour urinary salt excretion. Total salt intake increased with increasing body weight. Body weight-adjusted salt intake was greater in participants with hypertension than in those without hypertension. Systolic blood pressure, estimated glomerular filtration rate, and urinary albumin were independently correlated with body weight-adjusted salt intake after adjustment for possible cardiovascular risk factors. Excessive body weight-adjusted salt intake could be related to an increase in blood pressure and hypertensive organ damage. Adjustment for body weight might therefore provide clinically important information when assessing individual salt intake. Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

The processing of enriched germanium for the Majorana   Demonstrator  and R&D for a next generation double-beta decay experiment

DOE PAGES

Abgrall, N.; Arnquist, I. J.; Avignone III, F. T.; ...

2017-10-07

The Majorana Demonstrator is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluidsmore » from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.« less

COMPLEX EVOLUTION OF BILE SALTS IN BIRDS

PubMed Central

Hagey, Lee R.; Vidal, Nicolas; Hofmann, Alan F.; Krasowski, Matthew D.

2010-01-01

Bile salts are the major end-metabolites of cholesterol and are important in lipid digestion and shaping of the gut microflora. There have been limited studies of bile-salt variation in birds. The purpose of our study was to determine bile-salt variation among birds and relate this variation to current avian phylogenies and hypotheses on the evolution of bile salt pathways. We determined the biliary bile-salt composition of 405 phylogenetically diverse bird species, including 7 paleognath species. Bile salt profiles were generally stable within bird families. Complex bile-salt profiles were more common in omnivores and herbivores than in carnivores. The structural variation of bile salts in birds is extensive and comparable to that seen in surveys of bile salts in reptiles and mammals. Birds produce many of the bile salts found throughout nonavian vertebrates and some previously uncharacterized bile salts. One difference between birds and other vertebrates is extensive hydroxylation of carbon-16 of bile salts in bird species. Comparison of our data set of bird bile salts with that of other vertebrates, especially reptiles, allowed us to infer evolutionary changes in the bile salt synthetic pathway. PMID:21113274

Microplastic Pollution in Table Salts from China.

PubMed

Yang, Dongqi; Shi, Huahong; Li, Lan; Li, Jiana; Jabeen, Khalida; Kolandhasamy, Prabhu

2015-11-17

Microplastics have been found in seas all over the world. We hypothesize that sea salts might contain microplastics, because they are directly supplied by seawater. To test our hypothesis, we collected 15 brands of sea salts, lake salts, and rock/well salts from supermarkets throughout China. The microplastics content was 550-681 particles/kg in sea salts, 43-364 particles/kg in lake salts, and 7-204 particles/kg in rock/well salts. In sea salts, fragments and fibers were the prevalent types of particles compared with pellets and sheets. Microplastics measuring less than 200 μm represented the majority of the particles, accounting for 55% of the total microplastics, and the most common microplastics were polyethylene terephthalate, followed by polyethylene and cellophane in sea salts. The abundance of microplastics in sea salts was significantly higher than that in lake salts and rock/well salts. This result indicates that sea products, such as sea salts, are contaminated by microplastics. To the best of our knowledge, this is the first report on microplastic pollution in abiotic sea products.

Modeling Episodic Ephemeral Brine Lake Evaporation and Salt Crystallization on the Bonneville Salt Flats, Utah

NASA Astrophysics Data System (ADS)

Liu, T.; Harman, C. J.; Kipnis, E. L.; Bowen, B. B.

2017-12-01

Public concern about apparent reductions in the areal extent of the Bonneville Salt Flat (BSF) and perceived changes in inundation frequency has motivated renewed interest in the hydrologic and geochemical behavior of this salt playa. In this study, we develop a numerical modeling framework to simulate the relationship between hydrometeorologic variability, brine evaporation and salt crystallization processes on BSF. The BSF, locates in Utah, is the remnant of paleo-lake Bonneville, and is capped by up to 1 meter of salt deposition over a 100 km2 area. The BSF has two distinct hydrologic periods each year: a winter wet periods with standing surface brine and the summer dry periods when the brine is evaporated, exposing the surface salt crust. We develop a lumped non-linear dynamical models coupling conservation expressions from water, dissolved salt and thermal energy to investigate the seasonal and diurnal behavior of brine during the transition from standing brine to exposed salt at BSF. The lumped dynamic models capture important nonlinear and kinetic effects introduced by the high ionic concentration of the brine, including the pronounced effect of the depressed water activity coefficient on evaporation. The salt crystallization and dissolution rate is modeled as a kinetic process linearly proportional to the degree of supersaturation of brine. The model generates predictions of the brine temperature and the solute and solvent masses controlled by diurnal net radiation input and aerodynamic forcing. Two distinct mechanisms emerge as potential controls on salt production and dissolution: (1) evapo-concentration and (2) changes in solubility related to changes in brine temperature. Although the evaporation of water is responsible for ultimate disappearance of the brine each season ,variation in solubility is found to be the dominant control on diurnal cycles of salt precipitation and dissolution in the BSF case. Most salt is crystallized during nighttime, but the

Weak hydrogen bonding and fluorous interactions in the chloride and bromide salts of 4-[(2,2,3,3-tetrafluoropropoxy)methyl]pyridinium.

PubMed

Lu, Norman; Wei, Rong Jyun; Lin, Kwan Yu; Alagesan, Mani; Wen, Yuh Sheng; Liu, Ling Kang

2017-04-01

Neutralization of 4-[(2,2,3,3-tetrafluoropropoxy)methyl]pyridine with hydrohalo acids HX (X = Cl and Br) yielded the pyridinium salts 4-[(2,2,3,3-tetrafluoropropoxy)methyl]pyridinium chloride, C 9 H 10 F 4 NO + ·Cl - , (1), and 4-[(2,2,3,3-tetrafluoropropoxy)methyl]pyridinium bromide, C 9 H 10 F 4 NO + ·Br - , (2), both carrying a fluorous side chain at the para position of the pyridinium ring. Single-crystal X-ray diffraction techniques revealed that (1) and (2) are isomorphous. The halide anions accept four hydrogen bonds from N-H, ortho-C-H and CF 2 -H groups. Two cations and two anions form a centrosymmetric dimeric building block, utilizing complimentary N-H...X...H-Csp 3 connections. These dimers are further crosslinked, utilizing another complimentary Csp 2 -H...X...H-Csp 2 connection. The pyridinium rings are π-stacked, forming columns running parallel to the a axis that make angles of ca 44-45° with the normal to the pyridinium plane. There are also supramolecular C-H...F-C interactions, namely bifurcated C-H...F and bifurcated C-F...H interactions; additionally, one type II C-F...F-C halogen bond has been observed.

Near-field effect in the infrared range through periodic Germanium subwavelength arrays.

PubMed

Dong, Wei; Hirohata, Toru; Nakajima, Kazutoshi; Wang, Xiaoping

2013-11-04

Using finite-difference-time-domain simulation, we have studied the near-field effect of Germanium (Ge) subwavelength arrays designed in-plane with a normal incidence. Spectra of vertical electric field component normal to the surface show pronounced resonance peaks in an infrared range, which can be applied in a quantum well infrared photodetector. Unlike the near-field optics in metallic systems that are commonly related to surface plasmons, the intense vertical field along the surface of the Ge film can be interpreted as a combination of diffraction and waveguide theory. The existence of the enhanced field is confirmed by measuring the Fourier transform infrared spectra of fabricated samples. The positions of the resonant peaks obtained in experiment are in good agreement with our simulations.

Dot size effects of nanocrystalline germanium on charging dynamics of memory devices

PubMed Central

2013-01-01

The dot size of nanocrystalline germanium (NC Ge) which impacts on the charging dynamics of memory devices has been theoretically investigated. The calculations demonstrate that the charge stored in the NC Ge layer and the charging current at a given oxide voltage depend on the dot size especially on a few nanometers. They have also been found to obey the tendency of initial increase, then saturation, and lastly, decrease with increasing dot size at any given charging time, which is caused by a compromise between the effects of the lowest conduction states and the capacitance of NC Ge layer on the tunneling. The experimental data from literature have also been used to compare and validate the theoretical analysis. PMID:23305228

Replacement of salt by a novel potassium- and magnesium-enriched salt alternative improves the cardiovascular effects of ramipril.

PubMed Central

Mervaala, E. M.; Paakkari, I.; Laakso, J.; Nevala, R.; Teräväinen, T. M.; Fyhrquist, F.; Vapaatalo, H.; Karppanen, H.

1994-01-01

1. The influence of salt (sodium chloride; NaCl) (an additional 6% in the diet) and that of a novel sodium-reduced, potassium-, magnesium-, and L-lysine-enriched salt alternative on the cardiovascular effects of ramipril was studied in stroke-prone spontaneously hypertensive rats in a 6-week study. The intake of sodium chloride was adjusted to the same level by adding the salt alternative at a 1.75 times higher amount than regular salt. 2. Salt produced a marked rise in blood pressure and induced cardiac hypertrophy and significant mortality, while the salt alternative neither increased blood pressure nor caused any mortality and produced less cardiac hypertrophy than salt. 3. Ramipril treatment at a daily dose of 3 mg kg-1 normalized blood pressure and prevented the development of cardiac hypertrophy of rats on control diet. These effects of ramipril were blocked by the addition of salt but were only slightly attenuated by the addition of the salt alternative. The mortality in the salt group was prevented by ramipril. 4. Responses of mesenteric arterial rings in vitro were examined at the end of the study. Salt, but not the salt alternative, increased vascular contractile responses to noradrenaline. Ramipril treatment improved the arterial relaxation responses to acetylcholine and to sodium nitroprusside. The vascular relaxation enhancing effect of ramipril was blocked by salt but only slightly attenuated by the salt alternative. 5. Ramipril treatment did not significantly increase plasma renin activity in the presence or in the absence of salt supplementation. The salt alternative did not cause hyperkalaemia, either alone or in combination with ramipril treatment.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8032605

Iodized salt sales in the United States.

PubMed

Maalouf, Joyce; Barron, Jessica; Gunn, Janelle P; Yuan, Keming; Perrine, Cria G; Cogswell, Mary E

2015-03-10

Iodized salt has been an important source of dietary iodine, a trace element important for regulating human growth, development, and metabolic functions. This analysis identified iodized table salt sales as a percentage of retail salt sales using Nielsen ScanTrack. We identified 1117 salt products, including 701 salt blends and 416 other salt products, 57 of which were iodized. When weighted by sales volume in ounces or per item, 53% contained iodized salt. These findings may provide a baseline for future monitoring of sales of iodized salt.

Laser-induced self-organization in silicon-germanium thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weizman, M.; Nickel, N. H.; Sieber, I.

We report on the formation of self-organized structures in thin films of silicon-germanium (Si{sub 1-x}Ge{sub x}) with 0.3

Properties of the exotic metastable ST12 germanium allotrope

PubMed Central

Zhao, Zhisheng; Zhang, Haidong; Kim, Duck Young; Hu, Wentao; Bullock, Emma S.; Strobel, Timothy A.

2017-01-01

The optical and electronic properties of semiconducting materials are of great importance to a vast range of contemporary technologies. Diamond-cubic germanium is a well-known semiconductor, although other ‘exotic' forms may possess distinct properties. In particular, there is currently no consensus for the band gap and electronic structure of ST12-Ge (tP12, P43212) due to experimental limitations in sample preparation and varying theoretical predictions. Here we report clear experimental and theoretical evidence for the intrinsic properties of ST12-Ge, including the first optical measurements on bulk samples. Phase-pure bulk samples of ST12-Ge were synthesized, and the structure and purity were verified using powder X-ray diffraction, transmission electron microscopy, Raman and wavelength/energy dispersive X-ray spectroscopy. Optical measurements indicate that ST12-Ge is a semiconductor with an indirect band gap of 0.59 eV and a direct optical transition at 0.74 eV, which is in good agreement with electrical transport measurements and our first-principles calculations. PMID:28045027

Properties of the exotic metastable ST12 germanium allotrope

DOE PAGES

Zhao, Zhisheng; Zhang, Haidong; Kim, Duck Young; ...

2017-01-03

The optical and electronic properties of semiconducting materials are of great importance to a vast range of contemporary technologies. Diamond-cubic germanium is a well-known semiconductor, although other ‘exotic’ forms may possess distinct properties. In particular, there is currently no consensus for the band gap and electronic structure of ST12-Ge (tP12, P4 32 12) due to experimental limitations in sample preparation and varying theoretical predictions. Here we report clear experimental and theoretical evidence for the intrinsic properties of ST12-Ge, including the first optical measurements on bulk samples. Phase-pure bulk samples of ST12-Ge were synthesized, and the structure and purity were verifiedmore » using powder X-ray diffraction, transmission electron microscopy, Raman and wavelength/energy dispersive X-ray spectroscopy. Lastly, optical measurements indicate that ST12-Ge is a semiconductor with an indirect band gap of 0.59 eV and a direct optical transition at 0.74 eV, which is in good agreement with electrical transport measurements and our first-principles calculations.« less

Ultra-Low Noise Germanium Neutrino Detection system (ULGeN).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabrera-Palmer, Belkis; Barton, Paul

Monitoring nuclear power plant operation by measuring the antineutrino flux has become an active research field for safeguards and non-proliferation. We describe various efforts to demonstrate the feasibility of reactor monitoring based on the detection of the Coherent Neutrino Nucleus Scattering (CNNS) process with High Purity Germanium (HPGe) technology. CNNS detection for reactor antineutrino energies requires lowering the electronic noise in low-capacitance kg-scale HPGe detectors below 100 eV as well as stringent reduction in other particle backgrounds. Existing state- of-the-art detectors are limited to an electronic noise of 95 eV-FWHM. In this work, we employed an ultra-low capacitance point-contact detectormore » with a commercial integrated circuit preamplifier- on-a-chip in an ultra-low vibration mechanically cooled cryostat to achieve an electronic noise of 39 eV-FWHM at 43 K. We also present the results of a background measurement campaign at the Spallation Neutron Source to select the area with sufficient low background to allow a successful first-time measurement of the CNNS process.« less

Community solar salt production in Goa, India

PubMed Central

2012-01-01

Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa’s riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans. Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1–2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested. Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced. The aim of this review is to describe salt farming in Goa’s history, importance of salt production as a community activity, traditional method of salt production and the

Community solar salt production in Goa, India.

PubMed

Mani, Kabilan; Salgaonkar, Bhakti B; Das, Deepthi; Bragança, Judith M

2012-12-01

Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa's riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans.Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1-2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested.Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced.The aim of this review is to describe salt farming in Goa's history, importance of salt production as a community activity, traditional method of salt production and the biota

Moderate (20%) fructose-enriched diet stimulates salt-sensitive hypertension with increased salt retention and decreased renal nitric oxide.

PubMed

Gordish, Kevin L; Kassem, Kamal M; Ortiz, Pablo A; Beierwaltes, William H

2017-04-01

Previously, we reported that 20% fructose diet causes salt-sensitive hypertension. In this study, we hypothesized that a high salt diet supplemented with 20% fructose (in drinking water) stimulates salt-sensitive hypertension by increasing salt retention through decreasing renal nitric oxide. Rats in metabolic cages consumed normal rat chow for 5 days (baseline), then either: (1) normal salt for 2 weeks, (2) 20% fructose in drinking water for 2 weeks, (3) 20% fructose for 1 week, then fructose + high salt (4% NaCl) for 1 week, (4) normal chow for 1 week, then high salt for 1 week, (5) 20% glucose for 1 week, then glucose + high salt for 1 week. Blood pressure, sodium excretion, and cumulative sodium balance were measured. Systolic blood pressure was unchanged by 20% fructose or high salt diet. 20% fructose + high salt increased systolic blood pressure from 125 ± 1 to 140 ± 2 mmHg ( P  < 0.001). Cumulative sodium balance was greater in rats consuming fructose + high salt than either high salt, or glucose + high salt (114.2 ± 4.4 vs. 103.6 ± 2.2 and 98.6 ± 5.6 mEq/Day19; P  < 0.05). Sodium excretion was lower in fructose + high salt group compared to high salt only: 5.33 ± 0.21 versus 7.67 ± 0.31 mmol/24 h; P  < 0.001). Nitric oxide excretion was 2935 ± 256  μ mol/24 h in high salt-fed rats, but reduced by 40% in the 20% fructose + high salt group (2139 ± 178  μ mol /24 hrs P  < 0.01). Our results suggest that fructose predisposes rats to salt-sensitivity and, combined with a high salt diet, leads to sodium retention, increased blood pressure, and impaired renal nitric oxide availability. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits

DOE PAGES

Turchi, Craig S.; Vidal, Judith; Bauer, Matthew

2018-03-14

This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.

Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turchi, Craig S.; Vidal, Judith; Bauer, Matthew

This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.

High-energy proton radiation damage of high-purity germanium detectors

NASA Technical Reports Server (NTRS)

Pehl, R. H.; Varnell, L. S.; Metzger, A. E.

1978-01-01

Quantitative studies of radiation damage in high-purity germanium gamma-ray detectors due to high-energy charged particles have been carried out; two 1.0 cm thick planar detectors were irradiated by 6 GeV/c protons. Under proton bombardment, degradation in the energy resolution was found to begin below 7 x 10 to the 7th protons/sq cm and increased proportionately in both detectors until the experiment was terminated at a total flux of 5.7 x 10 to the 8th protons/sq cm, equivalent to about a six year exposure to cosmic-ray protons in space. At the end of the irradiation, the FWHM resolution measured at 1332 keV stood at 8.5 and 13.6 keV, with both detectors of only marginal utility as a spectrometer due to the severe tailing caused by charge trapping. Annealing these detectors after proton damage was found to be much easier than after neutron damage.

Inverting polar domains via electrical pulsing in metallic germanium telluride

PubMed Central

Nukala, Pavan; Ren, Mingliang; Agarwal, Rahul; Berger, Jacob; Liu, Gerui; Johnson, A. T. Charlie; Agarwal, Ritesh

2017-01-01

Germanium telluride (GeTe) is both polar and metallic, an unusual combination of properties in any material system. The large concentration of free-carriers in GeTe precludes the coupling of external electric field with internal polarization, rendering it ineffective for conventional ferroelectric applications and polarization switching. Here we investigate alternate ways of coupling the polar domains in GeTe to external electrical stimuli through optical second harmonic generation polarimetry and in situ TEM electrical testing on single-crystalline GeTe nanowires. We show that anti-phase boundaries, created from current pulses (heat shocks), invert the polarization of selective domains resulting in reorganization of certain 71o domain boundaries into 109o boundaries. These boundaries subsequently interact and evolve with the partial dislocations, which migrate from domain to domain with the carrier-wind force (electrical current). This work suggests that current pulses and carrier-wind force could be external stimuli for domain engineering in ferroelectrics with significant current leakage. PMID:28401949

Quantitative determination of zero-gravity effects on electronic materials processing germanium crystal growth with simultaneous interface demarcation experiment MA-060, section 5

NASA Technical Reports Server (NTRS)

Gatos, H. C.; Witt, A. F.; Lichtensteiger, M.; Herman, C. J.

1982-01-01

The crystal growth and segregation characteristics of a melt in a directional solidification configuration under near zero g conditions were investigated. The germanium (doped with gallium) system was selected because it was extensively studied on Earth and because it lends itself to a very detailed macroscopic and microscopic characterization. An extensive study was performed of the germanium crystals grown during the Apollo-Soyuz Test Project mission. It was found that single crystal growth was achieved and that the interface demarcation functioned successfully. On the basis of the results obtained to date, there is no indication that convection driven by thermal or surface tension gradients was present in the melt. The gallium segregation, in the absence of gravity, was found to be fundamentally different in its initial and its subsequent stages from that of the ground based tests. None of the existing theoretical models for growth and segregation can account for the observed segregation behavior in the absence of gravity.

Optimal Cooling of High Purity Germanium Spectrometers for Missions to Planets and Moons

NASA Astrophysics Data System (ADS)

Chernenko, A.; Kostenko, V.; Konev, S.; Rybkin, B.; Paschin, A.; Prokopenko, I.

2004-04-01

Gamma-ray spectrometers based on high purity germanium (HPGe) detectors are ultimately sensitive instruments for composition studies of surfaces of planets and moons. However, they require deep cooling well below 120K for the entire duration of space mission, and this challenges the feasibility of such instruments in the era of small and cost-efficient missions. In this paper we summarise our experience in the field of the theoretical and experimental studies of optimal cryogenic cooling of gamma-ray spectrometers based on HPGe detectors in order to find out how efficient, light and compact these instruments could be, provided such technologies like cryogenic heat pipe diodes (HPDs), efficient thermal insulation and efficient miniature cryocoolers are used.

Ionomic and metabolic responses to neutral salt or alkaline salt stresses in maize (Zea mays L.) seedlings.

PubMed

Guo, Rui; Shi, LianXuan; Yan, Changrong; Zhong, Xiuli; Gu, FengXue; Liu, Qi; Xia, Xu; Li, Haoru

2017-02-10

Soil salinity and alkalinity present a serious threat to global agriculture. However, most of the studies have focused on neutral salt stress, and the information on the metabolic responses of plants to alkaline salt stress is limited. This investigation aimed at determining the influence of neutral salt and alkaline salt stresses on the content of metal elements and metabolites in maize plant tissues, by using mixtures of various proportions of NaCl, NaHCO 3 , Na 2 SO 4 , and Na 2 CO 3 . We found that alkaline salt stress suppressed more pronouncedly the photosynthesis and growth of maize plants than salinity stress. Under alkaline salt stress conditions, metal ions formed massive precipitates, which ultimately reduced plant nutrient availability. On the other hand, high neutral salt stress induced metabolic changes in the direction of gluconeogenesis leading to the enhanced formation of sugars as a reaction contributing to the mitigation of osmotic stress. Thus, the active synthesis of sugars in shoots was essential to the development of salt tolerance. However, the alkaline salt stress conditions characterized by elevated pH values suppressed substantially the levels of photosynthesis, N metabolism, glycolysis, and the production of sugars and amino acids. These results indicate the presence of different defensive mechanisms responsible for the plant responses to neutral salt and alkaline salt stresses. In addition, the increased concentration of organic acids and enhanced metabolic energy might be potential major factors that can contribute to the maintenance intracellular ion balance in maize plants and counteract the negative effects of high pH under alkaline salt stress.

The effect of hydrocarbons on the microstructural evolution in rock salt: a case study on hydrocarbon bearing Ara salt from the South Oman Salt Basin

NASA Astrophysics Data System (ADS)

Schmatz, Joyce; Urai, Janos L.; Wübbeler, Franziska M. M.; Sadler, Marc

2014-05-01

It has been shown that dilatant deformation promotes the incorporation of hydrocarbons into typically low permeable rock salt (Schoenherr et al., 2007). However, there is not much knowledge on subsequent mechanisms related to recrystallization processes, which cause morphological and chemical changes of the carbonic inclusions. This work aims to contribute to an increased understanding of fluid inclusion dynamics related to grain boundary migration recrystallization and hence to facilitate the interpretation of complex microstructures in recrystallized, multiphase salt rocks. In this case study we investigate hydrocarbon-impregnated salt from the Cambrian Ara Group in the South Oman Salt Basin. The samples were cored from cm-m thick anhydrite-salt sequences overlying hydrocarbon bearing carbonate stringers in 3300 m depth. The anhydrite layers consist mainly of fine-grained anhydrite, which contains calcite, dolomite, and olivine inclusions. Solid bitumen and lighter hydrocarbon phases are observed in between the anhydrite grains and along cracks. Anhydrite layers host salt veins, which contain fragments of anhydrite. These fragments do not differ in composition or structure from the host material and the related vein microstructures indicate crack-seal mechanisms. Halite in the salt layers is almost entirely recrystallized with solid inclusions consisting of anhydrite, calcite, dolomite and olivine with hydrocarbon-coatings present inside grains and along grain boundaries. Solid inclusions cause pinning indicated by a decreased recrystallized grain size and by the presence of grains with preserved substructures representing earlier deformation phases. We observe two types of carbonic inclusions: I) solid bitumen coatings along grain boundaries and microcracks, interpreted to be incorporated into the salt in an overpressure state that allowed dilatancy of the salt, and II) less degraded, liquid hydrocarbons along grain boundaries in the vicinity of the anhydrite

Proteomic analysis of salt stress and recovery in leaves of Vigna unguiculata cultivars differing in salt tolerance.

PubMed

de Abreu, Carlos Eduardo Braga; Araújo, Gyedre dos Santos; Monteiro-Moreira, Ana Cristina de Oliveira; Costa, José Hélio; Leite, Hugo de Brito; Moreno, Frederico Bruno Mendes Batista; Prisco, José Tarquinio; Gomes-Filho, Enéas

2014-08-01

Cowpea cultivars differing in salt tolerance reveal differences in protein profiles and adopt different strategies to overcome salt stress. Salt-tolerant cultivar shows induction of proteins related to photosynthesis and energy metabolism. Salinity is a major abiotic stress affecting plant cultivation and productivity. The objective of this study was to examine differential proteomic responses to salt stress in leaves of the cowpea cultivars Pitiúba (salt tolerant) and TVu 2331 (salt sensitive). Plants of both cultivars were subjected to salt stress (75 mM NaCl) followed by a recovery period of 5 days. Proteins extracted from leaves of both cultivars were analyzed by two-dimensional electrophoresis (2-DE) under salt stress and after recovery. In total, 22 proteins differentially regulated by both salt and recovery were identified by LC-ESI-MS/MS. Our current proteome data revealed that cowpea cultivars adopted different strategies to overcome salt stress. For the salt-tolerant cultivar (Pitiúba), increase in abundance of proteins involved in photosynthesis and energy metabolism, such as rubisco activase, ribulose-5-phosphate kinase (Ru5PK) (EC 2.7.1.19), glycine decarboxylase (EC 1.4.4.2) and oxygen-evolving enhancer (OEE) protein 2, was observed. However, these vital metabolic processes were more profoundly affected in salt-sensitive cultivar (TVu), as indicated by the down-regulation of OEE protein 1, Mn-stabilizing protein-II, carbonic anhydrase (EC 4.2.1.1) and Rubisco (EC 4.1.1.39), leading to energy reduction and a decline in plant growth. Other proteins differentially regulated in both cultivars corresponded to different physiological responses. Overall, our results provide information that could lead to a better understanding of the molecular basis of salt tolerance and sensitivity in cowpea plants.

Production of chlorine from chloride salts

DOEpatents

Rohrmann, Charles A.

1981-01-01

A process for converting chloride salts and sulfuric acid to sulfate salts and elemental chlorine is disclosed. A chloride salt and sulfuric acid are combined in a furnace where they react to produce a sulfate salt and hydrogen chloride. Hydrogen chloride from the furnace contacts a molten salt mixture containing an oxygen compound of vanadium, an alkali metal sulfate and an alkali metal pyrosulfate to recover elemental chlorine. In the absence of an oxygen-bearing gas during the contacting, the vanadium is reduced, but is regenerated to its active higher valence state by separately contacting the molten salt mixture with an oxygen-bearing gas.

Salt-Sensitive Hypertension: Perspectives on Intrarenal Mechanisms

PubMed Central

Majid, Dewan S.A.; Prieto, Minolfa C.; Navar, L Gabriel

2015-01-01

Salt sensitive hypertension is characterized by increases in blood pressure in response to increases in dietary salt intake and is associated with an enhanced risk of cardiovascular and renal morbidity. Although researchers have sought for decades to understand how salt sensitivity develops in humans, the mechanisms responsible for the increases in blood pressure in response to high salt intake are complex and only partially understood. Until now, scientists have been unable to explain why some individuals are salt sensitive and others are salt resistant. Although a central role for the kidneys in the development of salt sensitivity and hypertension has been generally accepted, it is also recognized that hypertension is of multifactorial origin and a variety of factors can induce, or prevent, blood pressure responsiveness to the manipulation of salt intake. Excess salt intake in susceptible persons may also induce inappropriate central and sympathetic nervous system responses and increase the production of intrarenal angiotensin II, catecholamines and other factors such as oxidative stress and inflammatory cytokines. One key factor is the concomitant inappropriate or paradoxical activation of the intrarenal renin-angiotensin system, by high salt intake. This is reflected by the increases in urinary angiotensinogen during high salt intake in salt sensitive models. A complex interaction between neuroendocrine factors and the kidney may underlie the propensity for some individuals to retain salt and develop salt-dependent hypertension. In this review, we focus mainly on the renal contributions that provide the mechanistic link between chronic salt intake and the development of hypertension. PMID:26028244

Salt movements and faulting of the overburden - can numerical modeling predict the fault patterns above salt structures?

NASA Astrophysics Data System (ADS)

Clausen, O. R.; Egholm, D. L.; Wesenberg, R.

2012-04-01

Salt deformation has been the topic of numerous studies through the 20th century and up until present because of the close relation between commercial hydrocarbons and salt structure provinces of the world (Hudec & Jackson, 2007). The fault distribution in sediments above salt structures influences among other things the productivity due to the segmentation of the reservoir (Stewart 2006). 3D seismic data above salt structures can map such fault patterns in great detail and studies have shown that a variety of fault patterns exists. Yet, most patterns fall between two end members: concentric and radiating fault patterns. Here we use a modified version of the numerical spring-slider model introduced by Malthe-Sørenssen et al.(1998a) for simulating the emergence of small scale faults and fractures above a rising salt structure. The three-dimensional spring-slider model enables us to control the rheology of the deforming overburden, the mechanical coupling between the overburden and the underlying salt, as well as the kinematics of the moving salt structure. In this presentation, we demonstrate how the horizontal component on the salt motion influences the fracture patterns within the overburden. The modeling shows that purely vertical movement of the salt introduces a mesh of concentric normal faults in the overburden, and that the frequency of radiating faults increases with the amount of lateral movements across the salt-overburden interface. The two end-member fault patterns (concentric vs. radiating) can thus be linked to two different styles of salt movement: i) the vertical rising of a salt indenter and ii) the inflation of a 'salt-balloon' beneath the deformed strata. The results are in accordance with published analogue and theoretical models, as well as natural systems, and the model may - when used appropriately - provide new insight into how the internal dynamics of the salt in a structure controls the generation of fault patterns above the structure. The

Bile salts as semiochemicals in fish

USGS Publications Warehouse

Buchinger, Tyler J.; Li, Weiming; Johnson, Nicholas S.

2014-01-01

Bile salts are potent olfactory stimuli in fishes; however the biological functions driving such sensitivity remain poorly understood. We provide an integrative review of bile salts as semiochemicals in fish. First, we present characteristics of bile salt structure, metabolism, and function that are particularly relevant to chemical communication. Bile salts display a systematic pattern of structural variation across taxa, are efficiently synthesized, and are stable in the environment. Bile salts are released into the water via the intestine, urinary tract, or gills, and are highly water soluble. Second, we consider the potential role of bile salts as semiochemicals in the contexts of detecting nearby fish, foraging, assessing risk, migrating, and spawning. Lastly, we suggest future studies on bile salts as semiochemicals further characterize release into the environment, behavioral responses by receivers, and directly test the biological contexts underlying olfactory sensitivity.

Just add a pinch of salt!--current directions for the use of salt in recipes in Australian magazines.

PubMed

Webster, Jacqui; Dunford, Elizabeth; Barzi, Federica; Neal, Bruce

2010-02-01

Australians currently consume too much salt causing adverse consequences for health. The media play an important role in the provision of nutrition advice to consumers. Previous research shows that many foods advertized in consumer magazines are high in salt, but little research has examined magazine recipes in this context. The aim of this project was to summarize directions for salt use in recipes in leading Australian magazines. In August 2007 and 2008, the top 10 magazines by circulation that included at least five recipes, were examined. Standardized information was collected about directions for salt use in recipes. Three hundred and thirty recipes were identified in 2007 and 417 in 2008. About 68% of recipes included high-salt ingredients, 37% instructed to season with salt, 10% instructed to add a specific quantity of salt and 15% recommended selection of low-salt ingredients. There was substantial variability in directions for salt use in recipes between magazines, but no clear differences between 2007 and 2008. Many recipes advised to add salt in direct contradiction to national dietary guidelines. There is clear potential for editorial guidelines on salt use in recipes to play a role in advancing public health efforts in Australia and other such nations.

Salt Lake City, Utah

NASA Technical Reports Server (NTRS)

2002-01-01

Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

Correlation Between Optical Properties And Chemical Composition Of Sputter-deposited Germanium Cxide (GeO x) Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, Neil R.; Grant, J. T.; Sun, L.

2014-03-18

Germanium oxide (GeO x) films were grown on (1 0 0) Si substrates by reactive Direct-Current (DC) magnetron sputter-deposition using an elemental Ge target. The effects of oxygen gas fraction, Г = O 2/(Ar + O 2), on the deposition rate, structure, chemical composition and optical properties of GeOx films have been investigated. The chemistry of the films exhibits an evolution from pure Ge to mixed Ge + GeO + GeO 2 and then finally to GeO 2 upon increasing Г from 0.00 to 1.00. Grazing incidence X-ray analysis indicates that the GeO x films grown were amorphous. The opticalmore » properties probed by spectroscopic ellipsometry indicate that the effect of Г is significant on the optical constants of the GeO x films. The measured index of refraction (n) at a wavelength (λ) of 550 nm is 4.67 for films grown without any oxygen, indicating behavior characteristic of semiconducting Ge. The transition from germanium to mixed Ge + GeO + GeO 2 composition is associated with a characteristic decrease in n (λ = 550 nm) to 2.62 and occurs at Г = 0.25. Finally n drops to 1.60 for Г = 0.50–1.00, where the films become GeO 2. A detailed correlation between Г, n, k and stoichiometry in DC sputtered GeO x films is presented and discussed.« less

Chemical Functionalization of Germanium with Dextran Brushes for Immobilization of Proteins Revealed by Attenuated Total Reflection Fourier Transform Infrared Difference Spectroscopy.

PubMed

Schartner, Jonas; Hoeck, Nina; Güldenhaupt, Jörn; Mavarani, Laven; Nabers, Andreas; Gerwert, Klaus; Kötting, Carsten

2015-07-21

Protein immobilization studied by attenuated total reflection Fourier transform infrared (ATR-FT-IR) difference spectroscopy is an emerging field enabling the study of proteins at atomic detail. Gold or glass surfaces are frequently used for protein immobilization. Here, we present an alternative method for protein immobilization on germanium. Because of its high refractive index and broad spectral window germanium is the best material for ATR-FT-IR spectroscopy of thin layers. So far, this technique was mainly used for protein monolayers, which lead to a limited signal-to-noise ratio. Further, undesired protein-protein interactions can occur in a dense layer. Here, the germanium surface was functionalized with thiols and stepwise a dextran brush was generated. Each step was monitored by ATR-FT-IR spectroscopy. We compared a 70 kDa dextran with a 500 kDa dextran regarding the binding properties. All surfaces were characterized by atomic force microscopy, revealing thicknesses between 40 and 110 nm. To analyze the capability of our system we utilized N-Ras on mono-NTA (nitrilotriacetic acid) functionalized dextran, and the amount of immobilized Ras corresponded to several monolayers. The protein stability and loading capacity was further improved by means of tris-NTA for immobilization. Small-molecule-induced changes were revealed with an over 3 times higher signal-to-noise ratio compared to monolayers. This improvement may allow the observation of very small and so far hidden changes in proteins upon stimulus. Furthermore, we immobilized green fluorescent protein (GFP) and mCherry simultaneously enabling an analysis of the surface by fluorescence microscopy. The absence of a Förster resonance energy transfer (FRET) signal demonstrated a large protein-protein distance, indicating an even distribution of the protein within the dextran.

Influence of pre-salt topographic features on supra-salt deformation in Mediterranean basins: Geology vs. physical models

NASA Astrophysics Data System (ADS)

Ferrer, Oriol; Vidal-Royo, Oskar; Gratacós, Oscar; Roca, Eduard; Muñoz, Josep Anton; Esestime, Paolo; Rodriguez, Karyna; Yazmin Piragauta, Mary; Feliu, Nil

2017-04-01

The presence of a thick Messinian evaporite unit is a well known feature of the Mediterranean basins. This salt unit is composed of three sub-units (Lower, Mobile and Upper Units) in the Northwest Mediterranean. In contrast, in the Eastern Mediterranean it is characterized by a multilayered evaporite sequence. In both regions the salt acted as a detachment favoring the downslope gravitational failure of the overlying sediments in a thin-skinned deformation regime (e.g. Liguro-Provençal or Levant basins). As a result, these salt-bearing passive margins exhibit the classical three-domain structural zonation characterized by upslope extension, intermediate translation and downslope contraction. Nevertheless, the presence of pre-salt reliefs (e.g. irregularly eroded palaeotopography or volcanic edifices) is rather common in the translational domain of the Northwestern Mediterranean (e.g. Liguro-Provençal and West Corsica margins). In this scenario, pre-salt reliefs act as flow barriers and hinder salt drainage. When their summit lies close or above the top salt, these structures may partially or fully block salt flow. They also disrupt locally the structural zonation of the passive margin and constrain cover deformation. In contrast, in the Eastern Mediterranean the Eratosthenes seamount is characterized by a large scale submerged massif (ca. 120 km in size) that significantly influenced the structural evolution of the surrounding areas. This inherited relief acted as a buttress and deflected the Messinian salt flow constraining supra-salt deformation (e.g. Levant Basin and Nile margin). In addition, the geometry of the Eratosthenes seamount also restrained the structural style of the allochthonous salt that was expulsed during the development of the Cyprus subduction zone to the north. Using an experimental approach (sandbox models) and new analysis techniques, we investigate salt and supra-salt deformation in response to two different types of pre-salt relief: 1

Whitecaps, sea-salt aerosols, and climate

NASA Astrophysics Data System (ADS)

Anguelova, Magdalena Dimitrova

Oceanic whitecaps are the major source of sea-salt aerosols. Because these aerosols are dominant in remote marine air, they control the radiative properties of the clean background atmosphere by scattering sunlight, changing cloud properties and lifetime, and providing media for chemical reactions. Including sea-salt effects in climate models improves predictions, but simulating their generation is first necessary. To make the sea-salt generation function currently used in climate models more relevant for aerosol investigations, this study proposes two modifications. First, the conventional relation between whitecap coverage, W, and the 10-meter wind speed, U10, used in typical generation functions is expanded to include additional factors that affect whitecaps and sea-salt aerosol formation. Second, the sea-salt generation function is extended to smaller sizes; sea-salt aerosol with initial radii from 0.4 to 20 mum can now be modeled. To achieve these goals, this thesis develops a new method for estimating whitecap coverage on a global scale using satellite measurements of the brightness temperature of the ocean surface. Whitecap coverage evaluated with this method incorporates the effects of atmospheric stability, sea-surface temperature, salinity, wind fetch, wind duration, and the amount of surface-active material. Assimilating satellite-derived values for whitecap coverage in the sea-salt generation function incorporates the effects of all environmental factors on sea-salt production and predicts realistic sea-salt aerosol loadings into the atmosphere. An extensive database of whitecap coverage and sea-salt aerosol fluxes has been compiled with the new method and is used to investigate their spatial and temporal characteristics. The composite effect of all environmental factors suggests a more uniform latitudinal distribution of whitecaps and sea-salt aerosols than that predicted from wind speed alone. The effect of sea-surface temperature, TS, is

Germanium oxide removal by citric acid and thiol passivation from citric acid-terminated Ge(100).

PubMed

Collins, Gillian; Aureau, Damien; Holmes, Justin D; Etcheberry, Arnaud; O'Dwyer, Colm

2014-12-02

Many applications of germanium (Ge) are underpinned by effective oxide removal and surface passivation. This important surface treatment step often requires H-X (X = Cl, Br, I) or HF etchants. Here, we show that aqueous citric acid solutions are effective in the removal of GeOx. The stability of citric acid-treated Ge(100) is compared to HF and HCl treated surfaces and analyzed by X-ray photoelectron spectroscopy. Further Ge surface passivation was investigated by thiolation using alkane monothiols and dithiols. The organic passivation layers show good stability with no oxide regrowth observed after 3 days of ambient exposure.

Direct measurement of AC electrokinetics properties and capture frequencies of silicon and silicon-germanium nanowires

NASA Astrophysics Data System (ADS)

Merhej, M.; Honegger, T.; Bassani, F.; Baron, T.; Peyrade, D.; Drouin, D.; Salem, B.

2018-01-01

The assembly of semiconductor nanowires with nanoscale precision is crucial for their integration into functional systems. In this work, we propose a novel method to experimentally determine the real part of the Clausius-Mossotti factor (CMF) of silicon and silicon-germanium nanowires. The quantification of this CMF is measured with the nanowires velocities in a pure dielectrophoretic regime. This approach combined with a study on the connected nanowires alignment yield has led to a frequency of capture evaluation. In addition, we have also presented the morphology of nanowires assembly using dielectrophoresis for a wide frequency variation of AC electric fields.

Salt bridges: geometrically specific, designable interactions.

PubMed

Donald, Jason E; Kulp, Daniel W; DeGrado, William F

2011-03-01

Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. Copyright © 2010 Wiley-Liss, Inc.

Salting-out and salting-in: competitive effects of salt on the aggregation behavior of soy protein particles and their emulsifying properties.

PubMed

Xu, Hua-Neng; Liu, Yang; Zhang, Lianfu

2015-08-07

Emulsions stabilized by protein particles have gained increasing research attention due to their combined advantages of biocompatibility and superior stability. In this study, colloidal particles consisting of soy protein isolates (SPIs) prepared through a heat-treatment procedure are used to make oil-in-water emulsions at a protein concentration of 10 g L(-1) and a pH of 5.91. We investigate parallelly the effects of NaCl on the stability and rheological properties of the particle suspensions and their stabilized emulsions at salt concentrations of 0, 100 and 400 mM. The aggregation behavior of the particles is strongly dependent on the NaCl concentration, showing signs of sedimentation at low NaCl concentration (100 mM) but redispersion again at high NaCl concentration (400 mM). The extensive particle aggregation is beneficial to the formation of a continuous interfacial film for the emulsions, and hence results in a remarkable increase of creaming stability and interfacial viscoelastic moduli. The results can be explained in terms of two competitive effects of NaCl: salting-out and salting-in, which are attributed to complex electrostatic interactions between the particles as a function of NaCl concentration. The delicate balance between salting-out and salting-in provides an interesting insight into the nature of underlying protein particle interactions in aqueous suspensions and a possible mechanism for tailoring their emulsifying properties via salt effects.

Radiation-enhanced self- and boron diffusion in germanium

NASA Astrophysics Data System (ADS)

Schneider, S.; Bracht, H.; Klug, J. N.; Hansen, J. Lundsgaard; Larsen, A. Nylandsted; Bougeard, D.; Haller, E. E.

2013-03-01

We report experiments on proton radiation-enhanced self- and boron (B) diffusion in germanium (Ge) for temperatures between 515 ∘C and 720 ∘C. Modeling of the experimental diffusion profiles measured by means of secondary ion mass spectrometry is achieved on the basis of the Frenkel pair reaction and the interstitialcy and dissociative diffusion mechanisms. The numerical simulations ascertain concentrations of Ge interstitials and B-interstitial pairs that deviate by several orders of magnitude from their thermal equilibrium values. The dominance of self-interstitial related defects under irradiation leads to an enhanced self- and B diffusion in Ge. Analysis of the experimental profiles yields data for the diffusion of self-interstitials (I) and the thermal equilibrium concentration of BI pairs in Ge. The temperature dependence of these quantities provides the migration enthalpy of I and formation enthalpy of BI that are compared with recent results of atomistic calculations. The behavior of self- and B diffusion in Ge under concurrent annealing and irradiation is strongly affected by the property of the Ge surface to hinder the annihilation of self-interstitials. The limited annihilation efficiency of the Ge surface can be caused by donor-type surface states favored under vacuum annealing, but the physical origin remains unsolved.

Etching of germanium-tin using ammonia peroxide mixture

NASA Astrophysics Data System (ADS)

Dong, Yuan; Ong, Bin Leong; Wang, Wei; Zhang, Zheng; Pan, Jisheng; Gong, Xiao; Tok, Eng-Soon; Liang, Gengchiau; Yeo, Yee-Chia

2015-12-01

The wet etching of germanium-tin (Ge1-xSnx) alloys (4.2% < x < 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge1-xSnx is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge1-xSnx surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge0.918Sn0.082 samples. Both root-mean-square roughness and undulation periods of the Ge1-xSnx surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge1-xSnx using APM and may be used for the fabrication of Ge1-xSnx-based electronic and photonic devices.

Effects of Ge-132 and GeO2 on seed germination and seedling growth of Oenothera biennis L. under NaCl stress.

PubMed

Liu, Yan; Hou, Long-Yu; Li, Qing-Mei; Jiang, Ze-Ping; Gao, Wei-Dong; Zhu, Yan; Zhang, Hai-Bo

2017-01-01

To investigate the effects of β-carboxyethyl germanium sequioxide (Ge-132) and germanium dioxide (GeO 2 ) on improving salt tolerance of evening primrose (Oenothera biennis L.), seed germination, seedling growth, antioxidase and malondialdehyde (MDA) were observed under treatments of various concentrations (0, 5, 10, 20, 30 μM) of Ge in normal condition and in 50 mM NaCl solution. The results showed that both Ge-132 and GeO 2 treatments significantly increased seed germination percentage and shoot length in dose-dependent concentrations but inhibited early root elongation growth. 5-30 μM Ge-132 and 10, 20 μM GeO 2 treatments could significantly mitigate even eliminate harmful influence of salt, representing increased percentage of seed germination, root length, ratio between length of root and shoot, and decreased shoot length. These treatments also significantly decreased peroxidase (POD) and catalase (CAT) activities and MDA content. The mechanism is likely that Ge scavenges reactive oxygen species - especially hydrogen peroxide (H 2 O 2 ) - by its electron configuration 4S 2 4P 2 so as to reduce lipid peroxidation. This is the first report about the comparison of bioactivity effect of Ge-132 and GeO 2 on seed germination and seedling growth under salt stress. We conclude that Ge-132 is better than GeO 2 on promoting salt tolerance of seed and seedling.

Evolution of salt structures and Cretaceous uplift in westernmost Mississippi Salt basin, Madison Parish, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, A.H.M.S.; Pilger, R.H. Jr.

1988-09-01

Subsurface structures were interpreted from seismic images and well logs in the westernmost Mississippi Salt basin, Madison Parish, Louisiana. Structural and stratigraphic relations indicate that salt structures (Duckport, North Tallulah, South Coleman, Tallulah, and Walnut domes) have evolved through pillow, diapir, and postdiapir stages. Withdrawal synclines associated with each stage of growth occur adjacent to salt domes and are characterized by overthickening of sediments. Synclines associated with Walnut dome are particularly well recognized in the seismic data. Primary withdrawal synclines and present day turtle structure anticlines involve the deepest recorded reflections (possibly Jurassic carbonates) above seismically transparent Paleozoic basement andmore » overlying remnant salt. Similar early (Late Jurassic) salt mobility has recently been documented in North Louisiana and East Texas Salt basins. Secondary withdrawal synclines (Cotton Valley) are exceptionally overthickened and their axes are closer to the dome than the axes of primary synclines. Tertiary synclines are broad and appear to be active at present. North-south seismic sections that cross the approximate northwest boundary of the Mississippi Salt basin display post-middle Cretaceous upwarp (the Monroe Uplift) involving basement. Successively older Lower Cretaceous reflections are truncated to the north beneath an erosional surface. Upwarp apparently continued well into the Cenozoic.« less

Synthesis and properties of acetamidinium salts

PubMed Central

2011-01-01

Background Acetamidines are starting materials for synthesizing many chemical substances, such as imidazoles, pyrimidines and triazines, which are further used for biochemically active compounds as well as energetic materials. The aim of this study was to synthesise and characterise a range of acetamidinium salts in order to overcome the inconvenience connected with acetamidinium chloride, which is the only commercially available acetamidinium salt. Results Acetamidinium salts were synthesised and characterised by elemental analysis, mass spectrometry, NMR and - in the case of energetic salts - DTA. The structures of previously unknown acetamidinium salts were established by X-ray diffraction analysis. Hygroscopicities in 90% humidity of eight acetamidinium salts were evaluated. Conclusions The different values of hygroscopicity are corroborated by the structures determined by X-ray analysis. The acetamidinium salts with 2D layered structures (acetamidinium nitrate, formate, oxalate and dinitromethanide) show a lack of hygroscopicity, and the compounds with 3D type of structure (acetamidinium chloride, acetate, sulphate and perchlorate) and possessing rather large cavities are quite hygroscopic. PMID:22152129

Methods to Prepare Aluminum Salt-Adjuvanted Vaccines.

PubMed

Thakkar, Sachin G; Cui, Zhengrong

2017-01-01

Many human vaccines contain certain insoluble aluminum salts such as aluminum oxyhydroxide and aluminum hydroxyphosphate as vaccine adjuvants to boost the immunogenicity of the vaccines. Aluminum salts have been used as vaccine adjuvants for decades and have an established, favorable safety profile. However, preparing aluminum salts and aluminum salt-adjuvanted vaccines in a consistent manner remains challenging. This chapter discusses methods to prepare aluminum salts and aluminum salt-adjuvanted vaccines, factors to consider during preparation, and methods to characterize the vaccines after preparation.

Modeling and Simulation of - and Silicon Germanium-Base Bipolar Transistors Operating at a Wide Range of Temperatures.

NASA Astrophysics Data System (ADS)

Shaheed, M. Reaz

1995-01-01

Higher speed at lower cost and at low power consumption is a driving force for today's semiconductor technology. Despite a substantial effort toward achieving this goal via alternative technologies such as III-V compounds, silicon technology still dominates mainstream electronics. Progress in silicon technology will continue for some time with continual scaling of device geometry. However, there are foreseeable limits on achievable device performance, reliability and scaling for room temperature technologies. Thus, reduced temperature operation is commonly viewed as a means for continuing the progress towards higher performance. Although silicon CMOS will be the first candidate for low temperature applications, bipolar devices will be used in a hybrid fashion, as line drivers or in limited critical path elements. Silicon -germanium-base bipolar transistors look especially attractive for low-temperature bipolar applications. At low temperatures, various new physical phenomena become important in determining device behavior. Carrier freeze-out effects which are negligible at room temperature, become of crucial importance for analyzing the low temperature device characteristics. The conventional Pearson-Bardeen model of activation energy, used for calculation of carrier freeze-out, is based on an incomplete picture of the physics that takes place and hence, leads to inaccurate results at low temperatures. Plasma -induced bandgap narrowing becomes more pronounced in device characteristics at low temperatures. Even with modern numerical simulators, this effect is not well modeled or simulated. In this dissertation, improved models for such physical phenomena are presented. For accurate simulation of carrier freeze-out, the Pearson-Bardeen model has been extended to include the temperature dependence of the activation energy. The extraction of the model is based on the rigorous, first-principle theoretical calculations available in the literature. The new model is shown

Salt intake and dietary sources of salt on weekdays and weekend days in Australian adults.

PubMed

Nowson, Caryl; Lim, Karen; Land, Mary-Ann; Webster, Jacqui; Shaw, Jonathan E; Chalmers, John; Flood, Victoria; Woodward, Mark; Grimes, Carley

2018-02-01

To assess if there is a difference in salt intake (24 h urine collection and dietary recall) and dietary sources of salt (Na) on weekdays and weekend days. A cross-sectional study of adults who provided one 24 h urine collection and one telephone-administered 24 h dietary recall. Community-dwelling adults living in the State of Victoria, Australia. Adults (n 598) who participated in a health survey (53·5 % women; mean age 57·1 (95 % CI 56·2, 58·1) years). Mean (95 % CI) salt intake (dietary recall) was 6·8 (6·6, 7·1) g/d and 24 h urinary salt excretion was 8·1 (7·8, 8·3) g/d. Mean dietary and 24 h urinary salt (age-adjusted) were 0·9 (0·1, 1·6) g/d (P=0·024) and 0·8 (0·3, 1·6) g/d (P=0·0017), respectively, higher at weekends compared with weekdays. There was an indication of a greater energy intake at weekends (+0·6 (0·02, 1·2) MJ/d, P=0·06), but no difference in Na density (weekday: 291 (279, 304) mg/MJ; weekend: 304 (281, 327) mg/MJ; P=0·360). Cereals/cereal products and dishes, meat, poultry, milk products and gravy/sauces accounted for 71 % of dietary Na. Mean salt intake (24 h urine collection) was more than 60 % above the recommended level of 5 g salt/d and 8-14 % more salt was consumed at weekends than on weekdays. Substantial reductions in the Na content of staple foods, processed meat, sauces, mixed dishes (e.g. pasta), convenience and takeaway foods are required to achieve a significant consistent reduction in population salt intake throughout the week.

Measuring salt retention : [summary].

DOT National Transportation Integrated Search

2013-03-01

This project involves measuring and reporting the retention of salt and brine on the roadway as a result of using different salt spreaders, application speeds, and brine quantities. The research develops an evaluation methodology, directs the field c...

Great Salt Lake, Utah

USGS Publications Warehouse

Stephens, Doyle W.; Gardner, Joe F.

1999-01-01

This document is intended as a source of general information and facts about Great Salt Lake, Utah. This U.S. Geological Survey information sheet answers frequently asked questions about Great Salt Lake. Topics include: History, salinity, brine shrimp, brine flies, migratory birds, and recreation. Great Salt Lake, the shrunken remnant of prehistoric Lake Bonneville, has no outlet. Dissolved salts accumulate in the lake by evaporation. Salinity south of the causeway has ranged from 6 percent to 27 percent over a period of 22 years (2 to 7 times saltier than the ocean). The high salinity supports a mineral industry that extracts about 2 million tons of salt from the lake each year. The aquatic ecosystem consists of more than 30 species of organisms. Harvest of its best-known species, the brine shrimp, annually supplies millions of pounds of food for the aquaculture industry worldwide. The lake is used extensively by millions of migratory and nesting birds and is a place of solitude for people. All this occurs in a lake that is located at the bottom of a 35,000-square-mile drainage basin that has a human population of more than 1.5 million.

Overexpression of a partial fragment of the salt-responsive gene OsNUC1 enhances salt adaptation in transgenic Arabidopsis thaliana and rice (Oryza sativa L.) during salt stress.

PubMed

Sripinyowanich, Siriporn; Chamnanmanoontham, Nontalee; Udomchalothorn, Thanikarn; Maneeprasopsuk, Somporn; Santawee, Panudda; Buaboocha, Teerapong; Qu, Li-Jia; Gu, Hongya; Chadchawan, Supachitra

2013-12-01

The rice (Oryza sativa L.) nucleolin gene, OsNUC1, transcripts were expressed in rice leaves, flowers, seeds and roots but differentially expressed within and between two pairs of salt-sensitive and salt-resistant rice lines when subjected to salt stress. Salt-resistant lines exhibited higher OsNUC1 transcript expression levels than salt-sensitive lines during 0.5% (w/v) NaCl salt stress for 6d. Two sizes of OsNUC1 full-length cDNA were found in the rice genome database and northern blot analysis confirmed their existence in rice tissues. The longer transcript (OsNUC1-L) putatively encodes for a protein with a serine rich N-terminal, RNA recognition motifs in the central domain and a glycine- and arginine-rich repeat in the C-terminal domain, while the shorter one (OsNUC1-S) putatively encodes for the similar protein without the N-terminus. Without salt stress, OsNUC1-L expressing Arabidopsis thaliana Atnuc1-L1 plants displayed a substantial but incomplete revertant phenotype, whereas OsNUC1-S expression only induced a weak effect. However, under 0.5% (w/v) NaCl salt stress they displayed a higher relative growth rate, longer root length and a lower H2O2 level than the wild type plants, suggesting a higher salt resistance. Moreover, they displayed elevated AtSOS1 and AtP5CS1 transcript levels. We propose that OsNUC1-S plays an important role in salt resistance during salt stress, a new role for nucleolin in plants. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Salt or cocrystal of salt? Probing the nature of multicomponent crystal forms with infrared spectroscopy

NASA Astrophysics Data System (ADS)

da Silva, Cameron Capeletti; Guimarães, Freddy Fernandes; Ribeiro, Leandro; Martins, Felipe Terra

2016-10-01

The recognition of the nature of a multicomponent crystal form (solvate, salt, cocrystal or cocrystal of salt) is of great importance for pharmaceutical industry because it is directly related to the performance of a pharmaceutical ingredient, since there is interdependence between the structure, its energy and its physical properties. In this context, here we have identified the nature of multicomponent crystal forms of the anti-HIV drug lamivudine with mandelic acid through infrared spectroscopy. These investigated crystal forms were the known S-mandelic acid cocrystal of lamivudine R-mandelate trihydrate (1), a cocrystal of salt, and lamivudine R-mandelate (2), a salt. This approach also supports the identification and distinction of both ionized and unionized forms of mandelic acid in the infrared spectrum of 1. In this way, infrared spectroscopy can be useful to distinguish a cocrystal of salt from either salt or cocrystal forms. In the course of this study, for the first time we have also characterized and determined the crystal structure of R-mandelic acid cocrystal of sodium R-mandelate (3).

Algebraic reasoning and bat-and-ball problem variants: Solving isomorphic algebra first facilitates problem solving later.

PubMed

Hoover, Jerome D; Healy, Alice F

2017-12-01

The classic bat-and-ball problem is used widely to measure biased and correct reasoning in decision-making. University students overwhelmingly tend to provide the biased answer to this problem. To what extent might reasoners be led to modify their judgement, and, more specifically, is it possible to facilitate problem solution by prompting participants to consider the problem from an algebraic perspective? One hundred ninety-seven participants were recruited to investigate the effect of algebraic cueing as a debiasing strategy on variants of the bat-and-ball problem. Participants who were cued to consider the problem algebraically were significantly more likely to answer correctly relative to control participants. Most of this cueing effect was confined to a condition that required participants to solve isomorphic algebra equations corresponding to the structure of bat-and-ball question types. On a subsequent critical question with differing item and dollar amounts presented without a cue, participants were able to generalize the learned information to significantly reduce overall bias. Math anxiety was also found to be significantly related to bat-and-ball problem accuracy. These results suggest that, under specific conditions, algebraic reasoning is an effective debiasing strategy on bat-and-ball problem variants, and provide the first documented evidence for the influence of math anxiety on Cognitive Reflection Test performance.

EFFECTS OF CHRONIC EXCESS SALT FEEDING

PubMed Central

Dahl, Lewis K.; Heine, Martha

1961-01-01

Female rats were fed diets containing either excess sea salt or excess sodium chloride for periods up to 14 months. The hypertension produced by sea salt was more pronounced than that caused by sodium chloride alone, although the average amount of sodium chloride contained in the sea salt feeding was slightly less. The ions involved in this incremental effect of sea salt were not identified. PMID:13719314

Salt-Bridge Energetics in Halophilic Proteins

PubMed Central

Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K.

2014-01-01

Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are −3.0 kcal mol−1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of −5.0 kcal mol−1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (−10 kcal mol−1) exceeds than that of bridge term (−7 kcal mol−1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic

Salt-bridge energetics in halophilic proteins.

PubMed

Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K

2014-01-01

Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1) exceeds than that of bridge term (-7 kcal mol-1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its

Canister cryogenic system for cooling germanium semiconductor detectors in borehole and marine probes

USGS Publications Warehouse

Boynton, G.R.

1975-01-01

High resolution intrinsic and lithium-drifted germanium gamma-ray detectors operate at about 77-90 K. A cryostat for borehole and marine applications has been designed that makes use of prefrozen propane canisters. Uses of such canisters simplifies cryostat construction, and the rapid exchange of canisters greatly reduces the time required to restore the detector to full holding-time capability and enhances the safety of a field operation where high-intensity 252Cf or other isotopic sources are used. A holding time of 6 h at 86 K was achieved in the laboratory in a simulated borehole probe in which a canister 3.7 cm diameter by 57 cm long was used. Longer holding times can be achieved by larger volume canisters in marine probes. ?? 1975.

Temperature induced phonon behaviour in germanium selenide thin films probed by Raman spectroscopy

NASA Astrophysics Data System (ADS)

Taube, A.; Łapińska, A.; Judek, J.; Wochtman, N.; Zdrojek, M.

2016-08-01

Here we report a detailed study of temperature-dependent phonon properties of exfoliated germanium selenide thin films (several tens of nanometers thick) probed by Raman spectroscopy in the 70-350 K temperature range. The temperature-dependent behavior of the positions and widths of the Raman modes was nonlinear. We concluded that the observed effects arise from anharmonic phonon-phonon interactions and are explained by the phenomenon of optical phonon decay into acoustic phonons. At temperatures above 200 K, the position of the Raman modes tended to be linearly dependent, and the first order temperature coefficients χ were  -0.0277, -0.0197 and  -0.031 cm-1 K-1 for B 3g , A g(1) and A g(2) modes, respectively.

saltPAD: A New Analytical Tool for Monitoring Salt Iodization in Low Resource Settings

PubMed Central

Myers, Nicholas M.; Strydom, Emmerentia Elza; Sweet, James; Sweet, Christopher; Spohrer, Rebecca; Dhansay, Muhammad Ali; Lieberman, Marya

2016-01-01

We created a paper test card that measures a common iodizing agent, iodate, in salt. To test the analytical metrics, usability, and robustness of the paper test card when it is used in low resource settings, the South African Medical Research Council and GroundWork performed independent validation studies of the device. The accuracy and precision metrics from both studies were comparable. In the SAMRC study, more than 90% of the test results (n=1704) were correctly classified as corresponding to adequately or inadequately iodized salt. The cards are suitable for market and household surveys to determine whether salt is adequately iodized. Further development of the cards will improve their utility for monitoring salt iodization during production. PMID:29942380

Molten salt electrolyte separator

DOEpatents

Kaun, Thomas D.

1996-01-01

A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.

Electrochromic Salts, Solutions, and Devices

DOEpatents

Burrell, Anthony K.; Warner, Benjamin P.; McClesky, T. Mark

2008-11-11

Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

Electrochromic salts, solutions, and devices

DOEpatents

Burrell, Anthony K [Los Alamos, NM; Warner, Benjamin P [Los Alamos, NM; McClesky,7,064,212 T. Mark

2006-06-20

Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

Electrochromic Salts, Solutions, and Devices

DOEpatents

Burrell, Anthony K.; Warner, Benjamin P.; McClesky, T. Mark

2008-10-14

Electrochromic salts. Electrochromic salts of dicationic viologens such as methyl viologen and benzyl viologen associated with anions selected from bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and tris(trifluoromethylsulfonyl)methide are produced by metathesis with the corresponding viologen dihalide. They are highly soluble in molten quarternary ammonium salts and together with a suitable reductant provide electrolyte solutions that are used in electrochromic windows.

Discretionary salt use in airline meal service.

PubMed

Wallace, S; Wellman, N S; Dierkes, K E; Johnson, P M

1987-02-01

Salt use in airline meal service was studied through observation of returned meal trays of 932 passengers. Observation and weighing of salt packets on returned trays revealed that 64% of passengers did not salt their airline dinner, while 6% used the entire salt packet, 0.92 gm NaCl (362 mg Na). Average discretionary salt use among the 234 passengers (25%) who added salt was 0.57 gm NaCl (232 mg Na). Estimates of total sodium in the four airline dinners averaged 2.0 gm NaCl (786 mg Na). Laboratory assays of menu items produced by the airline foodservice differed 3% to 19% from estimated values. Sodium content of the four airline dinner menus was similar and did not affect salt use. Discretionary salt use was related to the total amount of entrée consumed but was not affected by the amount of salad consumed. It is postulated that salt use in the "captive" airline situation is predicated on consistent, habitual practices. Lowering sodium consumption in this setting may require alteration in both food preparation methods and quantity of salt presented in the packets.

Salt-induced epithelial-to-mesenchymal transition in Dahl salt-sensitive rats is dependent on elevated blood pressure.

PubMed

Wang, Y; Mu, J J; Liu, F Q; Ren, K Y; Xiao, H Y; Yang, Z; Yuan, Z Y

2014-02-01

Dietary salt intake has been linked to hypertension and cardiovascular disease. Accumulating evidence has indicated that salt-sensitive individuals on high salt intake are more likely to develop renal fibrosis. Epithelial-to-mesenchymal transition (EMT) participates in the development and progression of renal fibrosis in humans and animals. The objective of this study was to investigate the impact of a high-salt diet on EMT in Dahl salt-sensitive (SS) rats. Twenty-four male SS and consomic SS-13(BN) rats were randomized to a normal diet or a high-salt diet. After 4 weeks, systolic blood pressure (SBP) and albuminuria were analyzed, and renal fibrosis was histopathologically evaluated. Tubular EMT was evaluated using immunohistochemistry and real-time PCR with E-cadherin and alpha smooth muscle actin (α-SMA). After 4 weeks, SBP and albuminuria were significantly increased in the SS high-salt group compared with the normal diet group. Dietary salt intake induced renal fibrosis and tubular EMT as identified by reduced expression of E-cadherin and enhanced expression of α-SMA in SS rats. Both blood pressure and renal interstitial fibrosis were negatively correlated with E-cadherin but positively correlated with α-SMA. Salt intake induced tubular EMT and renal injury in SS rats, and this relationship might depend on the increase in blood pressure.

Laser-initiated explosive electron emission from flat germanium crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porshyn, V., E-mail: porshyn@uni-wuppertal.de; Mingels, S.; Lützenkirchen-Hecht, D.

2016-07-28

Flat Sb-doped germanium (100) crystals were investigated in the triode configuration under pulsed tunable laser illumination (pulse duration t{sub laser} = 3.5 ns and photon energy hν = 0.54–5.90 eV) and under DC voltages <10{sup 4} V. Large bunch charges up to ∼1 μC were extracted from the cathodes for laser pulses >1 MW/cm{sup 2} corresponding to a high quantum efficiency up to 3.3% and cathode currents up to 417 A. This laser-induced explosive electron emission (EEE) from Ge was characterized by its voltage-, laser power- and hν-sensitivity. The analysis of the macroscopic surface damage caused by the EEE is included as well. Moreover, we have carried out firstmore » direct measurements of electron energy distributions produced during the EEE from the Ge samples. The measured electron spectra hint for electron excitations to the vacuum level of the bulk and emission from the plasma plume with an average kinetic energy of ∼0.8 eV.« less

Cross-sectional survey of salt content in cheese: a major contributor to salt intake in the UK

PubMed Central

Hashem, Kawther M; He, Feng J; Jenner, Katharine H; MacGregor, Graham A

2014-01-01

Objective To investigate the salt (sodium chloride) content in cheese sold in UK supermarkets. Study design We carried out a cross-sectional survey in 2012, including 612 cheeses available in UK supermarkets. Methods The salt content (g/100 g) was collected from product packaging and nutrient information panels of cheeses available in the top seven retailers. Results Salt content in cheese was high with a mean (±SD) of 1.7±0.58 g/100 g. There was a large variation in salt content between different types of cheeses and within the same type of cheese. On average, halloumi (2.71±0.34 g/100 g) and imported blue cheese (2.71±0.83 g/100 g) contained the highest amounts of salt and cottage cheese (0.55±0.14 g/100 g) contained the lowest amount of salt. Overall, among the 394 cheeses that had salt reduction targets, 84.5% have already met their respective Department of Health 2012 salt targets. Cheddar and cheddar-style cheese is the most popular/biggest selling cheese in the UK and has the highest number of products in the analysis (N=250). On average, salt level was higher in branded compared with supermarket own brand cheddar and cheddar-style products (1.78±0.13 vs 1.72±0.14 g/100 g, p<0.01). Ninety per cent of supermarket own brand products met the 2012 target for cheddar and cheddar-style cheese compared with 73% of branded products (p=0.001). Conclusions Salt content in cheese in the UK is high. There is a wide variation in the salt content of different types of cheeses and even within the same type of cheese. Despite this, 84.5% of cheeses have already met their respective 2012 targets. These findings demonstrate that much larger reductions in the amount of salt added to cheese could be made and more challenging targets need to be set, so that the UK can continue to lead the world in salt reduction. PMID:25099933

Cross-sectional survey of salt content in cheese: a major contributor to salt intake in the UK.

PubMed

Hashem, Kawther M; He, Feng J; Jenner, Katharine H; MacGregor, Graham A

2014-07-18

To investigate the salt (sodium chloride) content in cheese sold in UK supermarkets. We carried out a cross-sectional survey in 2012, including 612 cheeses available in UK supermarkets. The salt content (g/100 g) was collected from product packaging and nutrient information panels of cheeses available in the top seven retailers. Salt content in cheese was high with a mean (±SD) of 1.7±0.58 g/100 g. There was a large variation in salt content between different types of cheeses and within the same type of cheese. On average, halloumi (2.71±0.34 g/100 g) and imported blue cheese (2.71±0.83 g/100 g) contained the highest amounts of salt and cottage cheese (0.55±0.14 g/100 g) contained the lowest amount of salt. Overall, among the 394 cheeses that had salt reduction targets, 84.5% have already met their respective Department of Health 2012 salt targets. Cheddar and cheddar-style cheese is the most popular/biggest selling cheese in the UK and has the highest number of products in the analysis (N=250). On average, salt level was higher in branded compared with supermarket own brand cheddar and cheddar-style products (1.78±0.13 vs 1.72±0.14 g/100 g, p<0.01). Ninety per cent of supermarket own brand products met the 2012 target for cheddar and cheddar-style cheese compared with 73% of branded products (p=0.001). Salt content in cheese in the UK is high. There is a wide variation in the salt content of different types of cheeses and even within the same type of cheese. Despite this, 84.5% of cheeses have already met their respective 2012 targets. These findings demonstrate that much larger reductions in the amount of salt added to cheese could be made and more challenging targets need to be set, so that the UK can continue to lead the world in salt reduction. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Differential expression of salt-responsive genes to salinity stress in salt-tolerant and salt-sensitive rice (Oryza sativa L.) at seedling stage.

PubMed

Singh, Vijayata; Singh, Ajit Pal; Bhadoria, Jyoti; Giri, Jitender; Singh, Jogendra; T V, Vineeth; Sharma, P C

2018-05-08

The understanding of physio-biochemical and molecular attributes along with morphological traits contributing to the salinity tolerance is important for developing salt-tolerant rice (Oryza sativa L.) varieties. To explore these facts, rice genotypes CSR10 and MI48 with contrasting salt tolerance were characterized under salt stress (control, 75 and 150 mM NaCl) conditions. CSR10 expressed higher rate of physio-biochemical parameters, maintained lower Na/K ratio in shoots, and restricted Na translocation from roots to shoots than MI48. The higher expression of genes related to the osmotic module (DREB2A and LEA3) and ionic module (HKT2;1 and SOS1) in roots of CSR10 suppresses the stress, enhances electrolyte leakage, promotes the higher compatible solute accumulation, and maintains cellular ionic homeostasis leading to better salt stress tolerance than MI48. This study further adds on the importance of these genes in salt tolerance by comparing their behaviour in contrasting rice genotypes and utilizing specific marker to identify salinity-tolerant accessions/donors among germplasm; overexpression of these genes which accelerate the selection procedure precisely has been shown.

Micromechanical processes in consolidated granular salt

DOE PAGES

Mills, Melissa Marie; Stormont, John C.; Bauer, Stephen J.

2018-03-27

Here, granular salt is likely to be used as backfill material and a seal system component within geologic salt formations serving as a repository for long-term isolation of nuclear waste. Pressure from closure of the surrounding salt formation will promote consolidation of granular salt, eventually resulting in properties comparable to native salt. Understanding dependence of consolidation processes on stress state, moisture availability, temperature, and time is important for demonstrating sealing functions and long-term repository performance. This study characterizes laboratory-consolidated granular salt by means of microstructural observations. Granular salt material from mining operations was obtained from the bedded Salado Formation hostingmore » the Waste Isolation Pilot Plant and the Avery Island salt dome. Laboratory test conditions included hydrostatic consolidation of jacketed granular salt with varying conditions of confining isochoric stress to 38 MPa, temperature to 250 °C, moisture additions of 1% by weight, time duration, and vented and non-vented states. Resultant porosities ranged between 1% and 22%. Optical and scanning electron microscopic techniques were used to ascertain consolidation mechanisms. From these investigations, samples with 1% added moisture or unvented during consolidation, exhibit clear pressure solution processes with tightly cohered grain boundaries and occluded fluid pores. Samples with only natural moisture content consolidated by a combination of brittle, cataclastic, and crystal plastic deformation. Recrystallization at 250 °C irrespective of moisture conditions was also observed. The range and variability of conditions applied in this study, combined with the techniques used to display microstructural features, are unique, and provide insight into an important area of governing deformation mechanism(s) occurring within salt repository applications.« less

Micromechanical processes in consolidated granular salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mills, Melissa Marie; Stormont, John C.; Bauer, Stephen J.

Here, granular salt is likely to be used as backfill material and a seal system component within geologic salt formations serving as a repository for long-term isolation of nuclear waste. Pressure from closure of the surrounding salt formation will promote consolidation of granular salt, eventually resulting in properties comparable to native salt. Understanding dependence of consolidation processes on stress state, moisture availability, temperature, and time is important for demonstrating sealing functions and long-term repository performance. This study characterizes laboratory-consolidated granular salt by means of microstructural observations. Granular salt material from mining operations was obtained from the bedded Salado Formation hostingmore » the Waste Isolation Pilot Plant and the Avery Island salt dome. Laboratory test conditions included hydrostatic consolidation of jacketed granular salt with varying conditions of confining isochoric stress to 38 MPa, temperature to 250 °C, moisture additions of 1% by weight, time duration, and vented and non-vented states. Resultant porosities ranged between 1% and 22%. Optical and scanning electron microscopic techniques were used to ascertain consolidation mechanisms. From these investigations, samples with 1% added moisture or unvented during consolidation, exhibit clear pressure solution processes with tightly cohered grain boundaries and occluded fluid pores. Samples with only natural moisture content consolidated by a combination of brittle, cataclastic, and crystal plastic deformation. Recrystallization at 250 °C irrespective of moisture conditions was also observed. The range and variability of conditions applied in this study, combined with the techniques used to display microstructural features, are unique, and provide insight into an important area of governing deformation mechanism(s) occurring within salt repository applications.« less

Solution synthesis of lead seeded germanium nanowires and branched nanowire networks and their application as Li-ion battery anodes

NASA Astrophysics Data System (ADS)

Flynn, Grace; Palaniappan, Kumaranand; Sheehan, Martin; Kennedy, Tadhg; Ryan, Kevin M.

2017-06-01

Herein, we report the high density growth of lead seeded germanium nanowires (NWs) and their development into branched nanowire networks suitable for application as lithium ion battery anodes. The synthesis of the NWs from lead seeds occurs simultaneously in both the liquid zone (solution-liquid-solid (SLS) growth) and solvent rich vapor zone (vapor-liquid-solid (VLS) growth) of a high boiling point solvent growth system. The reaction is sufficiently versatile to allow for the growth of NWs directly from either an evaporated catalyst layer or from pre-defined nanoparticle seeds and can be extended to allowing extensive branched nanowire formation in a secondary reaction where these seeds are coated onto existing wires. The NWs are characterized using TEM, SEM, XRD and DF-STEM. Electrochemical analysis was carried out on both the single crystal Pb-Ge NWs and the branched Pb-Ge NWs to assess their suitability for use as anodes in a Li-ion battery. Differential capacity plots show both the germanium wires and the lead seeds cycle lithium and contribute to the specific capacity that is approximately 900 mAh g-1 for the single crystal wires, rising to approximately 1100 mAh g-1 for the branched nanowire networks.

Drop the Salt! Assessing the impact of a public health advocacy strategy on Australian government policy on salt.

PubMed

Webster, Jacqui; Dunford, Elizabeth; Kennington, Sarah; Neal, Bruce; Chapman, Simon

2014-01-01

In 2007 the Australian Division of World Action on Salt and Health (AWASH) launched a campaign to encourage the Australian government to take action to reduce population salt intake. The objective of the present research was to assess the impact of the Drop the Salt! campaign on government policy. A review of government activities related to salt reduction was conducted and an advocacy strategy implemented to increase government action on salt. Advocacy actions were documented and the resulting outcomes identified. An analysis of stakeholder views on the effectiveness of the advocacy strategy was also undertaken. Settings Advocacy activities were coordinated through AWASH at the George Institute for Global Health in Sydney. All relevant State and Federal government statements and actions were reviewed and thirteen stakeholders with known interests or responsibilities regarding dietary salt, including food industry, government and health organisations, were interviewed. Stakeholder analysis affirmed that AWASH influenced the government's agenda on salt reduction and four key outputs were attributed to the campaign: (i) the Food Regulation Standing Committee discussions on salt, (ii) the Food and Health Dialogue salt targets, (iii) National Health and Medical Research Council partnership funding and (iv) the New South Wales Premier's Forum on Fast Foods. While it is not possible to definitively attribute changes in government policy to one organisation, stakeholder research indicated that the AWASH campaign increased the priority of salt reduction on the government's agenda. However, a coordinated government strategy on salt reduction is still required to ensure that the potential health benefits are fully realised.

Segmentation and pulse shape discrimination techniques for rejecting background in germanium detectors

NASA Technical Reports Server (NTRS)

Roth, J.; Primbsch, J. H.; Lin, R. P.

1984-01-01

The possibility of rejecting the internal beta-decay background in coaxial germanium detectors by distinguishing between the multi-site energy losses characteristic of photons and the single-site energy losses of electrons in the range 0.2 - 2 MeV is examined. The photon transport was modeled with a Monte Carlo routine. Background rejection by both multiple segmentation and pulse shape discrimination techniques is investigated. The efficiency of a six 1 cm-thick segment coaxial detector operating in coincidence mode alone is compared to that of a two-segment (1 cm and 5 cm) detector employing both front-rear coincidence and PSD in the rear segment to isolate photon events. Both techniques can provide at least 95 percent rejection of single-site events while accepting at least 80 percent of the multi-site events above 500 keV.

Self-monitoring urinary salt excretion in adults: A novel education program for restricting dietary salt intake

PubMed Central

YASUTAKE, KENICHIRO; SAWANO, KAYOKO; YAMAGUCHI, SHOKO; SAKAI, HIROKO; AMADERA, HATSUMI; TSUCHIHASHI, TAKUYA

2011-01-01

This study aimed to examine the usefulness of the self-monitoring of urinary salt excretion for educating individuals about the risk of excessive dietary salt intake. The subjects were 30 volunteers (15 men and 15 women) not consuming anti-hypertensive medication. The subjects measured urinary salt excretion at home for 4 weeks using a self-monitoring device. Blood pressure (BP), anthropometric variables and nutritional variables (by a dietary-habits questionnaire) were measured before and after the measurement of urinary salt excretion. Statistical analyses were performed, including paired t-tests, Chi-square test, Pearson’s product moment correlation coefficient and multiple linear regression analysis. In all subjects, the average urinary salt excretion over 4 weeks was 8.05±1.61 g/day and the range (maximum-minimum value) was 5.58±2.15 g/day. Salt excretion decreased significantly in weeks 3 and 4 (P<0.05 and P<0.01, respectively). Diastolic BP decreased from 77.7±14.3 (at baseline) to 74.3±13.3 after 4 weeks (P<0.05), while systolic BP and anthropometric variables remained unchanged. Nutrition surveys indicated that energy intake was correlated with salt intake both before and after the measurements; changes in both variables during the observation period were correlated (r=0.40, P<0.05). The percentage of subjects who were aware of the restriction in dietary salt intake increased from 47 to 90%. In conclusion, daily monitoring of the amount of urinary salt excretion using a self-monitoring device appears to be an effective educational tool for improving the quality of life of healthy adults. PMID:22977549

Self-monitoring urinary salt excretion in adults: A novel education program for restricting dietary salt intake.

PubMed

Yasutake, Kenichiro; Sawano, Kayoko; Yamaguchi, Shoko; Sakai, Hiroko; Amadera, Hatsumi; Tsuchihashi, Takuya

2011-07-01

This study aimed to examine the usefulness of the self-monitoring of urinary salt excretion for educating individuals about the risk of excessive dietary salt intake. The subjects were 30 volunteers (15 men and 15 women) not consuming anti-hypertensive medication. The subjects measured urinary salt excretion at home for 4 weeks using a self-monitoring device. Blood pressure (BP), anthropometric variables and nutritional variables (by a dietary-habits questionnaire) were measured before and after the measurement of urinary salt excretion. Statistical analyses were performed, including paired t-tests, Chi-square test, Pearson's product moment correlation coefficient and multiple linear regression analysis. In all subjects, the average urinary salt excretion over 4 weeks was 8.05±1.61 g/day and the range (maximum-minimum value) was 5.58±2.15 g/day. Salt excretion decreased significantly in weeks 3 and 4 (P<0.05 and P<0.01, respectively). Diastolic BP decreased from 77.7±14.3 (at baseline) to 74.3±13.3 after 4 weeks (P<0.05), while systolic BP and anthropometric variables remained unchanged. Nutrition surveys indicated that energy intake was correlated with salt intake both before and after the measurements; changes in both variables during the observation period were correlated (r=0.40, P<0.05). The percentage of subjects who were aware of the restriction in dietary salt intake increased from 47 to 90%. In conclusion, daily monitoring of the amount of urinary salt excretion using a self-monitoring device appears to be an effective educational tool for improving the quality of life of healthy adults.

Salt stress-induced changes in antioxidative defense system and proteome profiles of salt-tolerant and sensitive Frankia strains.

PubMed

Srivastava, Amrita; Singh, Anumeha; Singh, Satya S; Mishra, Arun K

2017-04-16

An appreciation of comparative microbial survival is most easily done while evaluating their adaptive strategies during stress. In the present experiment, antioxidative and whole cell proteome variations based on spectrophotometric analysis and SDS-PAGE and 2-dimensional gel electrophoresis have been analysed among salt-tolerant and salt-sensitive Frankia strains. This is the first report of proteomic basis underlying salt tolerance in these newly isolated Frankia strains from Hippophae salicifolia D. Don. Salt-tolerant strain HsIi10 shows higher increment in the contents of superoxide dismutase, catalase and ascorbate peroxidase as compared to salt-sensitive strain HsIi8. Differential 2-DGE profile has revealed differential profiles for salt-tolerant and salt-sensitive strains. Proteomic confirmation of salt tolerance in the strains with inbuilt efficiency of thriving in nitrogen-deficient locales is a definite advantage for these microbes. This would be equally beneficial for improvement of soil nitrogen status. Efficient protein regulation in HsIi10 suggests further exploration for its potential use as biofertilizer in saline soils.

Molten salt electrolyte separator

DOEpatents

Kaun, T.D.

1996-07-09

The patent describes a molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication. 5 figs.

One-pot size-controlled growth of graphene-encapsulated germanium nanocrystals

NASA Astrophysics Data System (ADS)

Lee, Jae-Hyun; Lee, Eun-Kyung; Kang, Seog-Gyun; Jung, Su-Ho; Son, Seok-Kyun; Nam, Woo Hyun; Kim, Tae-Hoon; Choi, Byong Lyong; Whang, Dongmok

2018-05-01

To realize graphene-encapsulated semiconductor nanocrystals (NCs), an additional graphene coating process, which causes shape destruction and chemical contamination, has so far been inevitable. We report herein one-pot growth of uniform graphene-germanium core-shell nanocrystals (Ge@G NCs) in gram scale by the addition of methane as a carbon source during the thermal pyrolysis of germane. The methane plays a critical role in the growth of the graphene shell, as well as in the determination of the nucleation density and diameter of the NCs, similar to a surfactant in the liquid-phase growth of monodisperse NCs. By adjusting the gas ratio of precursors, a mixture of germane and methane, we can control the size of the Ge@G NCs in the range of ∼5-180 nm. The Ge@G NCs were characterized by various microscopic and spectroscopic tools, which indicated that the Ge core is single crystalline, and is completely covered by the graphene shell. We further investigated the merits of the graphene shell, which can enhance the electrical conductivity of nanocrystalline materials.

Improved WIMP-search reach of the CDMS II germanium data

DOE PAGES

Agnese, R.

2015-10-12

CDMS II data from the five-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector weakly interacting massive particle (WIMP)-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to ~5 keV, to increase sensitivity near a WIMP mass of 8 GeV/c 2. After unblinding, there were zero candidate events above a deposited energy of 10 keV and six events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of 1.8×10more » –44 and 1.18×10 –41 at 90% confidence for 60 and 8.6 GeV/c 2 WIMPs, respectively. This improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6) GeV/c 2 WIMPs.« less

Improved WIMP-search reach of the CDMS II germanium data

DOE PAGES

Agnese, R.

2015-10-12

CDMS II data from the five-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector weakly interacting massive particle (WIMP)-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to ~5 keV, to increase sensitivity near a WIMP mass of 8 GeV/c 2. After unblinding, there were zero candidate events above a deposited energy of 10 keV and six events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of 1.8×10more » –44 and 1.18×10 –41 at 90% confidence for 60 and 8.6 GeV/c 2 WIMPs, respectively. Furthermore, this improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6) GeV/c 2 WIMPs.« less

Spin-to-charge conversion for hot photoexcited electrons in germanium

NASA Astrophysics Data System (ADS)