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G V Brown, P Beiersdorfer, N Hell, E Magee
We have used the EBIT-I electron beam ion trap at the Lawrence Livermore National Laboratory and a duplicate Orion High Resolution X-ray Spectrometer (OHREX) to measure the relative efficiency of a spherically bent quartz (101̄1) crystal (2d = 6.687 Å) and a spherically bent germanium (111) crystal (2d = 6.532 Å). L-shell X-ray photons from highly charged molybdenum ions generated in EBIT-I were simultaneously focussed and Bragg reflected by each crystal, both housed in a single spectrometer, onto a single CCD X-ray detector...
November 2016: Review of Scientific Instruments
G A Wurden, L A Stephey, C Biedermann, M W Jakubowski, J P Dunn, M Gamradt
A high-resolution imaging system, consisting of megapixel mid-IR and visible cameras along the same line of sight, has been prepared for the new W7-X stellarator and was operated during Operational Period 1.1 to view one of the five inboard graphite limiters. The radial line of sight, through a large diameter (184 mm clear aperture) uncoated sapphire window, couples a direct viewing 1344 × 784 pixel FLIR SC8303HD camera. A germanium beam-splitter sends visible light to a 1024 × 1024 pixel Allied Vision Technologies Prosilica GX1050 color camera...
November 2016: Review of Scientific Instruments
Julia Schneider, Christian P Sindlinger, Sarah M Freitag, Hartmut Schubert, Lars Wesemann
Intramolecular germylene, stannylene, and plumbylene Lewis pairs were reacted with hexanal and yielded the cyclic addition products only with the germanium and tin reagents. In further reactivity studies, the hydroboration of aldehydes and ketones catalyzed by intramolecular germylene, stannylene, and plumbylene Lewis pairs was studied. In the case of the cyclic germylene Lewis pair, the product of the oxidative addition of pinacolborane at the germylene moiety was observed. According to stoichiometric as well as catalytic experiments, the intramolecular germylene Lewis pair acts as a catalyst in the hydroboration of aldehydes and ketones...
December 2, 2016: Angewandte Chemie
Sankha Chattopadhyay, Md Neyar Alam, Madhu Smita, Umesh Kumar, Sujata Saha Das, Luna Barua
Gallium-68 radioisotope is an excellent source in clinical positron emission tomography application due to its ease of availability from germanium-68 ((68) Ge)/gallium-68 ((68) Ga) generator having a shelf life of 1 year. In this paper, a modified method for purification of the primary eluate of (68) Ge-(68) Ga generator by using a small cation exchange resin (Dowex-50) column has been described. The breakthrough of (68) Ge before and after purification of (68) Ga eluate was 0.014% and 0.00027%, respectively...
December 1, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Tingting Tang, Jie Li, Yanfen Zhang, Chaoyang Li, Li Luo
We study spin Hall effect (SHE) of transmitted light in a three-layer waveguide with epsilon-near-zero (ENZ) metamaterial. As the increased loss of anisotropic ENZ metamaterial brings decreased propagation loss for oblique incidence, the transmission of incident light is enhanced which induces a different distribution of transverse shift peaks. Based on simulation results, the influences of ENZ permittivity components and thickness as well as gold layer thickness on transverse shift of left-circularly polarized light in ENZ/Au/ENZ waveguide are analyzed...
November 28, 2016: Optics Express
Stanislav Hrivňak, Jozef Uličný, Ladislav Mikeš, Angelica Cecilia, Elias Hamann, Tilo Baumbach, Libor Švéda, Zdenko Zápražný, Dušan Korytár, Eva Gimenez-Navarro, Ulrich H Wagner, Christoph Rau, Hartmut Greven, Patrik Vagovič
We present an improved, single-distance phase retrieval algorithm applicable for holographic X-ray imaging of biological objects for an in-line germanium Bragg Magnifier Microscope (BMM). The proposed algorithm takes advantage of a modified shrink-wrap algorithm for phase objects, robust unwrapping algorithm as well as other reasonable constraints applied to the wavefield at the object and the detector plane. The performance of the algorithm is analyzed on phantom objects and the results are shown and discussed...
November 28, 2016: Optics Express
Monireh Moayedi Pour Fard, Glenn Cowan, Odile Liboiron-Ladouceur
This paper experimentally demonstrates a design optimization of an evanescently-coupled waveguide germanium-on-silicon photodetector (PD) towards high-speed (> 30 Gb/s) applications. The resulting PD provides a responsivity of 1.09 A/W at 1550 nm, a dark current of 3.5 µA and bandwidth of 42.5 GHz at 2 V reverse-bias voltage. To optimize the PD, the impact of various design parameters on performance is investigated. A novel optimization methodology for the PD's responsivity based on the required bandwidth is developed...
November 28, 2016: Optics Express
Jake Fontana, Melissa Maldonado, Nicholas Charipar, Scott A Trammell, Rafaela Nita, Jawad Naciri, Alberto Pique, Banahalli Ratna, Anderson S L Gomes
We created centimeter-scale area metasurfaces consisting of a quasi-hexagonally close packed monolayer of gold nanospheres capped with alkanethiol ligands on glass substrates using a directed self-assembly approach. We experimentally characterized the morphology and the linear and nonlinear optical properties of metasurfaces. We show these metasurfaces, with interparticle gaps of 0.6 nm, are modeled well using a classical (without charge transfer) description. We find a large dispersion of linear refractive index, ranging from values less than vacuum, 0...
November 28, 2016: Optics Express
Mojdeh Naderi, Samaneh Zolghadri, Hassan Yousefnia, Ali Ramazani, Amir Reza Jalilian
OBJECTIVES: Gallium-68 DOTA-DPhe(1)-Tyr(3)-Octreotide ((68)Ga-DOTATOC) has been applied by several European centers for the treatment of a variety of human malignancies. Nevertheless, definitive dosimetric data are yet unavailable. According to the Society of Nuclear Medicine and Molecular Imaging, researchers are investigating the safety and efficacy of this radiotracer to meet Food and Drug Administration requirements. The aim of this study was to introduce the optimized procedure for (68)Ga-DOTATOC preparation, using a novel germanium-68 ((68)Ge)/(68)Ga generator in Iran and evaluate the absorbed doses in numerous organs with high accuracy...
2016: Asia Oceania Journal of Nuclear Medicine & Biology
Bishwajit Ganguly, Abul Kalam Biswas
This study reports for the first time that compounds of Ge (II) can function as superbases. Two B(N=PiPr3)2 groups attached to a germanium (II) center show a gas phase proton affinity of 296.2 kcal/mol, close to the range of a hyperbase as revealed by B3LYP-D3/6-31G(2d,p) level of theory. These DFT calculations showed better agreement of geometrical parameters for the reported stable germylene compound 1 than previously reported calculations at the B3LYP/6-31G(2d,p) and PBE/DZP level of theory. A systematic study performed with different substitutions of Ge(II) revealed that such system can achieve basicity close to a hyperbase...
November 30, 2016: Chemistry: a European Journal
K K Sriram, Simantini Nayak, Stefanie Pengel, Chia-Fu Chou, Andreas Erbe
The fabrication of sub-nanoliter fluidic channels is demonstrated, with merely 10 nm depth on germanium, using conventional semiconductor device fabrication methods and a polymer assisted room-temperature sealing method. As a first application, an ultralow volume (650 pL) was studied by ATR-IR spectroscopy. A detection limit of ∼7.9 × 10(10) molecules of human serum albumin (HSA) (∼0.2 mM) in D2O was achieved with highly specific ATR-IR spectroscopy.
November 30, 2016: Analyst
Mohammad Abu Shayeb, Thamer Alharbi, Muzahir Ali Baloch, Omar Abdul Rahman Alsamhan
Palm pits are used in various human and animal feed products. In this study, the natural radioactivity levels from soil and date palm pits of 9 samples collected from major date palm farms in three different regions (Buraidah, Al-Zulfi and Al-Majmaah) of Saudi Arabia were determined by using the high purity germanium (HPGe) gamma-ray spectrometer. The mean activity concentrations of (226)Ra, (232)Th, (137)Cs and (40)K in soil samples were 12.8 ± 2.2, 10.2 ± 2.1, 0.28 ± 0.10 and 329 ± 87 Bg kg(-1), respectively...
November 25, 2016: Journal of Environmental Radioactivity
Hao Geng, Jiayun Dai, Jinhua Li, Zengfeng Di, Xuanyong Liu
Germanium (Ge), as an elemental semiconductor material, has been an attractive candidate for manufacturing semiconductor microelectronic device. In the present investigation, to improve the biocompatibility of Ge-based device, graphene film is directly deposited on the Ge surface with different coverage area by controlling the growth time. Compared to bare Ge, the presence of graphene film entitles Ge with satisfactory antibacterial ability against Staphylococcus aureus (S.aureus), and acceptable antibacterial ability against Escherichia coli (E...
November 23, 2016: Scientific Reports
Fazel Shojaei, Hong Seok Kang
Based on the first-principles calculations, we predict that the monoclinic GeP can be exfoliated into two-dimensional (2D) monolayers. In fact, the interlayer van der Waals interactions are found to be comparable to those in black phosphorus. For the first time, we also elaborate mechanical and electronic properties of the monolayer for possible applications in optoelectronics. Although the monolayer is an indirect-gap semiconductor, it turns into a direct-gap material under appropriate strain. Namely, the material exhibits a direct gap of 2...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
Zhaowen Dong, Crispin R W Reinhold, Marc Schmidtmann, Thomas Müller
The synthesis of a bicyclic germylene from the reaction of a germole dianion with hafnocene dichloride is reported. This germylene is stabilized by a homoconjugative interaction of the dicoordinated germanium atom with a remote C=C double bond. First reactivity studies revealed its nucleophilic character and resulted in the synthesis of bimetallic hafnium/iron and hafnium/tungsten complexes with a germylene group linker.
November 17, 2016: Angewandte Chemie
Muhammad Usman, Shruti Mendiratta, Kuang-Lieh Lu
Metal-organic frameworks (MOFs) with low density, high porosity, and easy tunability of functionality and structural properties, represent potential candidates for use as semiconductor materials. The rapid development of the semiconductor industry and the continuous miniaturization of feature sizes of integrated circuits toward the nanometer (nm) scale require novel semiconductor materials instead of traditional materials like silicon, germanium, and gallium arsenide etc. MOFs with advantageous properties of both the inorganic and the organic components promise to serve as the next generation of semiconductor materials for the microelectronics industry with the potential to be extremely stable, cheap, and mechanically flexible...
November 18, 2016: Advanced Materials
Zhenzhou Cheng, Keisuke Goda
We present waveguide-integrated graphene devices for photonic gas sensing. In a gas environment, graphene's conductivity is changed by adsorbed gas molecules which serve as charge-carrier donors or acceptors. To accurately probe gas-induced variations in the graphene's conductivity, we optimize the graphene's Fermi level and spectral region. Then, we propose graphene-on-silicon and graphene-on-germanium suspended membrane slot waveguides in which propagating light in the waveguide has a strong interaction with the top graphene layer...
December 16, 2016: Nanotechnology
Lingkuan Meng, Xiaobin He, Jianfeng Gao, Junjie Li, Yayi Wei, Jiang Yan
A novel nanofabrication technique which can produce highly controlled silicon-based nanostructures in wafer scale has been proposed using a simple amorphous silicon (α-Si) material as an etch mask. SiO2 nanostructures directly fabricated can serve as nanotemplates to transfer into the underlying substrates such as silicon, germanium, transistor gate, or other dielectric materials to form electrically functional nanostructures and devices. In this paper, two typical silicon-based nanostructures such as nanoline and nanofin have been successfully fabricated by this technique, demonstrating excellent etch performance...
December 2016: Nanoscale Research Letters
Zhihao Jia, Qiang Cheng, Jinlin Song, Yifan Zhou, Yang Liu
This paper proposes an assembly structure incorporating two-dimensional silicon gratings and germanium nanorods applied to photovoltaic absorbers. The absorptance of the assembly structure is numerically investigated using the finite-difference time-domain method. The results demonstrate that such a structure can greatly improve the absorptance and conversion efficiency compared to the gratings or nanowires in the 300-1100 nm wavelength region. The average spectral absorptance of such a structure reaches up to 0...
November 1, 2016: Applied Optics
Ionel Stavarache, Valentin Adrian Maraloiu, Petronela Prepelita, Gheorghe Iordache
Obtaining high-quality materials, based on nanocrystals, at low temperatures is one of the current challenges for opening new paths in improving and developing functional devices in nanoscale electronics and optoelectronics. Here we report a detailed investigation of the optimization of parameters for the in situ synthesis of thin films with high Ge content (50 %) into SiO2. Crystalline Ge nanoparticles were directly formed during co-deposition of SiO2 and Ge on substrates at 300, 400 and 500 °C. Using this approach, effects related to Ge-Ge spacing are emphasized through a significant improvement of the spatial distribution of the Ge nanoparticles and by avoiding multi-step fabrication processes or Ge loss...
2016: Beilstein Journal of Nanotechnology
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