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Hazem H Abdelmaksoud, Taryn M Guinan, Nicolas H Voelcker
Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is a high-throughput analytical technique ideally suited for small molecule detection from different bodily fluids (e.g. saliva, urine, and blood plasma). Many SALDI-MS substrates require complex fabrication processes and further surface modifications. Furthermore, some substrates show instability upon exposure to ambient conditions and need to be kept under special inert conditions. We have successfully optimized mesoporous germanium (meso-pGe) using bipolar electrochemical etching (BEE) and efficiently applied meso-pGe as a SALDI-MS substrate for the detection of cocaine in the context of workplace, roadside, and anti-addictive drug compliance...
January 20, 2017: ACS Applied Materials & Interfaces
Sinho Choi, Yoon-Gyo Cho, Jieun Kim, Nam-Soon Choi, Hyun-Kon Song, Guoxiu Wang, Soojin Park
Porous structured materials have unique architectures and are promising for lithium-ion batteries to enhance performances. In particular, mesoporous materials have many advantages including a high surface area and large void spaces which can increase reactivity and accessibility of lithium ions. This study reports a synthesis of newly developed mesoporous germanium (Ge) particles prepared by a zincothermic reduction at a mild temperature for high performance lithium-ion batteries which can operate in a wide temperature range...
January 18, 2017: Small
Alan Y Liu, Jon Peters, Xue Huang, Daehwan Jung, Justin Norman, Minjoo L Lee, Arthur C Gossard, John E Bowers
We demonstrate the first electrically pumped continuous-wave (CW) III-V semiconductor lasers epitaxially grown on on-axis (001) silicon substrates without offcut or germanium layers, using InAs/GaAs quantum dots as the active region and an intermediate GaP buffer between the silicon and device layers. Broad-area lasers with uncoated facets achieve room-temperature lasing with threshold current densities around 860  A/cm<sup>2</sup> and 110 mW of single-facet output power for the same device...
January 15, 2017: Optics Letters
Wei-Chung Chang, Kuan-Wei Tseng, Hsing-Yu Tuan
Red Phosphorus (RP) is a promising anode material for lithium-ion battery due to its earth abundance and a high theoretical capacity of 2596 mA h g-1. Although RP-based anodes for lithium-ion batteries have been reported, they were all in the form of carbon/P composites, including P-graphene, P-graphite, P-CNTs and P-carbon black, in order to improve P's extremely low conductivity and large volume change during cycling process. Here we report the large-scale synthesis of red phosphorus nanoparticles (RPNPs) with sizes ranging from 100 to 200 nm by reacting PI3 with ethylene glycol in the presence of cetyltrimethylammonium bromide (CTAB) in ambient environment...
January 12, 2017: Nano Letters
Jens Trommer, André Heinzig, Uwe Mühle, Markus Löffler, Annett Winzer, Paul M Jordan, Jürgen Beister, Tim Baldauf, Marion Geidel, Barbara Adolphi, Ehrenfried Zschech, Thomas Mikolajick, Walter M Weber
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...
January 17, 2017: ACS Nano
Ravindra K Raut, Moumita Majumdar
The germanium(ii) center of dicationic compound 1 donates an electron pair to transition metal Ag(i) and Au(i) cations, leading to complexes 2 and 3 respectively. Complex 3 is stabilized by [Ge:](2+)→Au(i) σ-donation and π-back donation from filled d-orbitals of Au(i) to the two sets of p-orbitals available on Ge(ii) centers.
January 11, 2017: Chemical Communications: Chem Comm
Michael Jeffrey Sear, Alex Schenk, Anton Tadich, Benjamin Spencer, Christopher Wright, Alastair Stacey, Christopher Pakes
An ordered germanium terminated (100) diamond surface has been formed and characterised using a combination of low energy electron diffraction and synchrotron-based core level photoemission spectroscopy. A number of preparation methods are explored, in each case inducing a two domain (3x1) surface reconstruction. The surface becomes saturated with bonded germanium such that each (3x1) unit cell hosts 1.26 Ge atoms on average, and possesses a negative electron affinity of -0.71 eV.
January 9, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Tae-Hee Kim, Song Yi Park, Tack Ho Lee, Jeong Jaeki, Dong Suk Kim, Mark Swihart, Song Hyun-Kon, Jin Young Kim, Seongbeom Kim
Germanium exhibits both high charge capacity and high lithium diffusivity, both key requirements for electrode materials in high performance lithium ion batteries (LIBs). However, high volume expansion and segregation from the electrode during charge-discharge cycling have limited use of germanium in LIBs. Here, we demonstrate that ZnO decorated Ge nanoparticles (Ge@ZnO NPs) can overcome these limitations of Ge as an LIB anode material. We produced Ge NPs at high rates by laser pyrolysis of GeH4, then coated them with solution phase synthesized ZnO NPs...
January 9, 2017: Nanotechnology
Nikola Marković, Per Roos, Sven Poul Nielsen
The performance of a new gamma-gamma coincidence spectrometer system for environmental samples analysis at the Center for Nuclear Technologies of the Technical University of Denmark (DTU) is reported. Nutech Coincidence Low Energy Germanium Sandwich (NUCLeGeS) system consists of two HPGe detectors in a surface laboratory with a digital acquisition system used to collect the data in time-stamped list mode with 10ns time resolution. The spectrometer is used in both anticoincidence and coincidence modes.
December 24, 2016: Applied Radiation and Isotopes
Janine Kaden, Stephan I Brückner, Susanne Machill, Christoph Krafft, Andreas Pöppl, Eike Brunner
Iron incorporation into diatom biosilica was investigated for the species Stephanopyxis turris. It is known that several "foreign" elements (e.g., germanium, titanium, aluminum, zinc, iron) can be incorporated into the siliceous cell walls of diatoms in addition to silicon dioxide (SiO2). In order to examine the amount and form of iron incorporation, the iron content in the growth medium was varied during cultivation. Fe:Si ratios of isolated cell walls were measured by ICP-OES. SEM studies were performed to examine of a possible influence of excess iron during diatom growth upon cell wall formation...
January 7, 2017: Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
Marie-Christine Lépy, Sylvie Pierre, Raf Van Ammel, Maria Marouli
New measurements of photon emission intensities in the decay of U-235 were performed. Source was prepared by deposition of a U-235 solution on glass plate. Standardization was carried out by defined solid angle alpha counting, giving the reference activity with 0.7% relative combined uncertainty. Gamma spectrometry was performed with accurately calibrated high-purity germanium detectors. Corrections for source geometry and coincidence summing effects were applied. The reference line (185.72keV) intensity was obtained with 1...
December 23, 2016: Applied Radiation and Isotopes
Yingzi Liu, Farshad Mostafaei, Daniel Sowers, Ming-Jung Hsieh, Wei Zheng, Linda Nie
In the US alone, millions of workers, including over 300,000 welders, are at high risk of occupational manganese (Mn) exposure. Those who have been chronically exposed to excessive amount of Mn can develop severe neurological disorders similar, but not identical, to the idiopathic Parkinson's disease. One challenge to identify the health effects of Mn exposure is to find a reliable biomarker for exposure assessment, especially for long-term cumulative exposure. Mn's long biological half-life as well as its relatively high concentration in bone makes bone Mn (BnMn) a potentially valuable biomarker for Mn exposure...
January 6, 2017: Physiological Measurement
Karol Tarnowski, Tadeusz Martynkien, Paweł Mergo, Krzysztof Poturaj, Grzegorz Soboń, Wacław Urbańczyk
For the first time to our knowledge, we demonstrate a coherent supercontinuum in silica fibers reaching 2.2 µm in a long wavelength range. The process of supercontinuum generation was studied experimentally and numerically in two microstructured fibers with a germanium doped core, having flat all-normal chromatic dispersion optimized for pumping at 1.55 µm. The fibers were pumped with two pulse lasers operating at 1.56 µm with different pulse duration times equal respectively to 23 fs and 460 fs. The experimental results are in a good agreement with the simulations conducted by solving the generalized nonlinear Schrödinger equation with the split-step Fourier method...
December 26, 2016: Optics Express
Chiao Chang, Hui Li, Chien-Te Ku, Shih-Guo Yang, Hung Hsiang Cheng, Joshua Hendrickson, Richard A Soref, Greg Sun
We report the experimental fabrication and testing of a GeSn-based 320×256 image sensor focal plane array operating at -15°C in the 1.6-1.9 μm spectral range. For image readout, the 2D pixel array of Ge/GeSn/Ge p-i-n heterophotodiodes was flip-chip bonded to a customized silicon CMOS readout integrated circuit. The resulting camera chip was operated using back-side illumination. Successful imaging of a tungsten-filament light bulb was attained with observation of gray-scale "hot spot" infrared features not seen using a visible-light camera...
December 20, 2016: Applied Optics
Walter M Weber, Thomas Mikolajick
Research in the field of electronics of one-dimensional group-IV semiconductor structures has attracted increasing attention over the past 15 years. The exceptional combination of the unique one-dimensional 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 1-D group IV nanowires endows new device principles...
January 5, 2017: Reports on Progress in Physics
Georg R J Artus, Sandro Olveira, Debabrata Patra, Stefan Seeger
Chemical composition and shape determine the basic properties of any object. Commonly, chemical synthesis and shaping follow each other in a sequence, although their combination into a single process would be an elegant simplification. Here, a pathway of simultaneous synthesis and shaping as applied to polysiloxanes on the micro- and nanoscale is presented. Complex structures such as stars, chalices, helices, volcanoes, rods, or combinations thereof are obtained. Varying the shape-controlling reaction parameters including temperature, water saturation, and the type of substrate allows to direct the reaction toward specific structures...
January 3, 2017: Macromolecular Rapid Communications
Runwei Mo, David Rooney, Kening Sun, Hui Ying Yang
Flexible electrochemical energy storage devices have attracted extensive attention as promising power sources for the ever-growing field of flexible and wearable electronic products. However, the rational design of a novel electrode structure with a good flexibility, high capacity, fast charge-discharge rate and long cycling lifetimes remains a long-standing challenge for developing next-generation flexible energy-storage materials. Herein, we develop a facile and general approach to three-dimensional (3D) interconnected porous nitrogen-doped graphene foam with encapsulated Ge quantum dot/nitrogen-doped graphene yolk-shell nano architecture for high specific reversible capacity (1,220 mAh g(-1)), long cycling capability (over 96% reversible capacity retention from the second to 1,000 cycles) and ultra-high rate performance (over 800 mAh g(-1) at 40 C)...
January 4, 2017: Nature Communications
Yung-Chen Lin, Dongheun Kim, Zhen Li, Binh-Minh Nguyen, Nan Li, Shixiong Zhang, Jinkyoung Yoo
We report on strain-induced structural defect formation in core Si nanowires of a Si/Ge core/shell nanowire heterostructure and the influence of the structural defects on the electrochemical performances in lithium-ion battery anodes based on Si/Ge core/shell nanowire heterostructures. The induced structural defects consisting of stacking faults and dislocations in the core Si nanowire were observed for the first time. The generation of stacking faults in the Si/Ge core/shell nanowire heterostructure is observed to prefer settling in either only the Ge shell region or in both the Ge shell and Si core regions and is associated with the increase of the shell volume fraction...
January 19, 2017: Nanoscale
Shinya Fujii
 Hydrophobic interaction, as well as polar interactions such as hydrogen bonding and electrostatic interaction, plays an essential role in the interaction between biologically active compounds and their target molecules. Therefore, the application of novel hydrophobic structures other than simple hydrocarbons or aromatic rings is expected to be useful in the development of biologically active compounds with distinctive chemical and pharmacological properties. In this study, we developed various bioactive compounds bearing a boron cluster, silicon-containing or germanium-containing functionalities as novel hydrophobic structures...
2017: Yakugaku Zasshi: Journal of the Pharmaceutical Society of Japan
Y John Zhai
PURPOSE: To obtain an improved precise gamma efficiency calibration curve of HPGe (High Purity Germanium) detector with a new comprehensive approach. METHODS: Both of radioactive sources and Monte Carlo simulation (CYLTRAN) are used to determine HPGe gamma efficiency for energy range of 0-8 MeV. The HPGe is a GMX coaxial 280 cm(3) N-type 70% gamma detector. Using Momentum Achromat Recoil Spectrometer (MARS) at the K500 superconducting cyclotron of Texas A&M University, the radioactive nucleus (24) Al was produced and separated...
June 2016: Medical Physics
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