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Delphine Vallot, Olivier Caselles, Leonor Chaltiel, Anthony Fernandez, Erwan Gabiache, Lawrence Dierickx, Slimane Zerdoud, Mathilde Bauriaud, Frédéric Courbon
PURPOSE: The aim of this study was to evaluate the impact of using the Bayesian penalized likelihood (BPL) algorithm on a bismuth germanium oxide positron emission tomography (PET)/computed tomography (CT) system for F-FDG PET/CT exams in case of low injected activity and scan duration. MATERIALS AND METHODS: F-FDG respiratory gated PET/CT performed on 102 cancer patients, injected with ∼2 MBq/kg of F-FDG, were reconstructed using two algorithms: ordered subset expectation maximization (OSEM) and BPL...
November 2017: Nuclear Medicine Communications
Xiaolei Sun, Xueyi Lu, Shaozhuan Huang, Lixia Xi, Lixiang Liu, Bo Liu, Qunhong Weng, Lin Zhang, Oliver G Schmidt
Germanium is a promising anode material for lithium ion batteries because of its high theoretical specific capacity and low operation voltage. However, a significant challenge in using Ge-based anodes is the large volume variation during cycling that causes pulverization and capacity fade. Despite intense studies in the past decade, unsatisfactory cycling stability of the Ge-based electrodes still impedes their widespread applications. In this paper, we demonstrate a high performance electrode through the synergistic combination of a high-capacity Ge film grown on a three-dimensional current collector and an in-situ formed PVDF-HFP/SiO2 protective layer...
October 18, 2017: ACS Applied Materials & Interfaces
Daniel Burt, Abdelrahman Al-Attili, Zuo Li, Frédéric Gardès, Moïse Sotto, Naoki Higashitarumizu, Yasuhiko Ishikawa, Katsuya Oda, Osvaldo M Querin, Shinichi Saito, Robert Kelsall
A silicon compatible light source is crucial to develop a fully monolithic silicon photonics platform. Strain engineering in suspended Germanium membranes has offered a potential route for such a light source. However, biaxial structures have suffered from poor optical properties due to unfavorable strain distributions. Using a novel geometric approach and finite element modelling (FEM) structures with improved strain homogeneity were designed and fabricated. Micro-Raman (μ-Raman) spectroscopy was used to determine central strain values...
September 18, 2017: Optics Express
Jicheng Wang, Ci Song, Jing Hang, Zheng-Da Hu, Feng Zhang
A grating-coupled Otto configuration consisting of multilayer films including a few layers of graphene and a germanium prism is proposed. A sharp and sensitive Fano resonance appears when a graphene surface plasmon polaritons (GSPPs) mode from the graphene-dielectric interface couple with the planar waveguide (PWG) mode. We utilize the classical harmonic oscillator (CHO) to explain Fano resonance and study the influence of various parameters of the configuration on the reflection spectra. The highly sensitive sensor can be achieved by introducing detected materials into Otto structure...
October 2, 2017: Optics Express
Zhao Wang, Dixon Paez, Ahmed I Abd El-Rahman, Peng Wang, Liam Dow, John C Cartledge, Andrew P Knights
A method to stabilize the resonance wavelength of a depletion-type silicon micro-ring resonator modulator during high-speed operation is described. The method utilizes the intrinsic defect-mediated photo-absorption of a silicon waveguide and results in a modulator chip fabrication process that is free of heterogeneous integration (for example using germanium), thus significantly reducing the complexity and cost of manufacture. Residual defects, present after p-n junction formation, are found to produce an adequate photocurrent for use as a feedback signal, while an integrated heater is used to compensate for thermal drift via closed-loop control...
October 2, 2017: Optics Express
Gao Yi, Hyub Lee, Jiao Jiannan, Byung Jae Chun, Seunghwoi Han, Hyunwoong Kim, Yong Woo Kim, Donghwan Kim, Seung-Woo Kim, Young-Jin Kim
Third harmonic generation (THG) is a nonlinear optical phenomenon which can be applied in diverse research areas including interfacial studies, sub-wavelength light manipulation, and high sensitivity bio-molecular detection. Most precedent studies on THG have focused on dielectric and metallic materials, including silicon, gold, and germanium, due to their high nonlinear susceptibility. Sapphire, a widely-used optical substrate, has not been studied in depth for its third harmonic characteristics, despite its excellent optical transmission in the UV-visible range, high thermal conductance, and superior physical and chemical stability...
October 16, 2017: Optics Express
Léopold Virot, Daniel Benedikovic, Bertrand Szelag, Carlos Alonso-Ramos, Bayram Karakus, Jean-Michel Hartmann, Xavier Le Roux, Paul Crozat, Eric Cassan, Delphine Marris-Morini, Charles Baudot, Frédéric Boeuf, Jean-Marc Fédéli, Christophe Kopp, Laurent Vivien
Germanium photodetectors are considered to be mature components in the silicon photonics device library. They are critical for applications in sensing, communications, or optical interconnects. In this work, we report on design, fabrication, and experimental demonstration of an integrated waveguide PIN photodiode architecture that calls upon lateral double Silicon/Germanium/Silicon (Si/Ge/Si) heterojunctions. This photodiode configuration takes advantage of the compatibility with contact process steps of silicon modulators, yielding reduced fabrication complexity for transmitters and offering high-performance optical characteristics, viable for high-speed and efficient operation near 1...
August 7, 2017: Optics Express
Sanja Radosavljevic, Bart Kuyken, Gunther Roelkens
We present the design, fabrication and characterization of efficient fiber-to-chip grating couplers on a Germanium-on-Silicon (Ge-on-Si) and Germanium-on-silicon-on-insulator (Ge-on-SOI) platform in the 5 µm wavelength range. The best grating couplers on Ge-on-Si and Ge-on-SOI have simulated coupling efficiencies of -4 dB (40%) with a 3 dB bandwidth of 180 nm and -1.5 dB (70%) with a 3 dB bandwidth of 200 nm, respectively. Experimentally, we show a maximum efficiency of -5 dB (32%) and a 3 dB bandwidth of 100 nm for Ge-on-Si grating couplers, and a -4 dB (40%) efficiency with a 3 dB bandwidth of 180 nm for Ge-on-SOI couplers...
August 7, 2017: Optics Express
Wei Wang, Yuan Dong, Shuh-Ying Lee, Wan-Khai Loke, Dian Lei, Soon-Fatt Yoon, Gengchiau Liang, Xiao Gong, Yee-Chia Yeo
The floating-base germanium-tin (Ge1-xSnx) heterojunction phototransistor (HPT) is designed and investigated as an efficient optical receiver in the short-wave infrared range. Simulations indicate that as the Sn content increases, the responsivity significantly increases due to a higher absorption coefficient and a larger valence band offset between Ge and Ge1-xSnx. Ge0.935Sn0.065 HPTs that incorporated high-quality Ge0.935Sn0.065 film grown by molecular beam epitaxy were fabricated, demonstrating optical response beyond wavelength of 2003 nm...
August 7, 2017: Optics Express
K Mayer, L J Schiegerl, T Kratky, S Günther, T F Fässler
Molecules with low-valent Ge atoms are generally synthesized from organohalogen germanes as precursors. The Zintl phase K4Ge9 provides reactive building blocks for a targeted synthesis of germanium-rich molecules. The silylation of Ge9 clusters with chlorosilanes ClSiR2R', that carry unsaturated olefin groups R' leads to the introduction of olefinic side chains of variable lengths allowing for further reactions. The compounds K[Ge9{Si(SiMe3)3}2(SiPh2R')] (R' = -CH[double bond, length as m-dash]CH2 (1); -(CH2)3CH[double bond, length as m-dash]CH2 (2)) carry one such functionality, whereas K[Ge9(SiPh2R')3] (3 and 4) offer the possibility for an interconnection of clusters due to three functional groups on the Ge9 core...
October 16, 2017: Chemical Communications: Chem Comm
Tsukasa Aso, Yoshimune Ogata, Ryuta Makino
The modified sum-peak method can practically estimate radioactivity by using solely the peak and the sum peak count rate. In order to efficiently verify the method in various experimental conditions, a Geant4 based Monte Carlo simulation for a high-purity germanium detector system was applied. The energy spectra in the detector were simulated for a (60)Co point source in various source to detector distances. The calculated radioactivity shows good agreement with the number of decays in the simulation.
September 14, 2017: Applied Radiation and Isotopes
B R Jany, A Janas, F Krok
The quantitative composition of metal alloy nanowires on InSb semiconductor surface and gold nanostructures on germanium surface is determined by blind source separation (BSS) machine learning method using non-negative matrix factorization from energy dispersive X-ray spectroscopy (EDX) spectrum image maps measured in a scanning electron microscope (SEM). The BSS method blindly decomposes the collected EDX spectrum image into three source components, which correspond directly to the X-ray signals coming from the supported metal nanostructures, bulk semiconductor signal, and carbon background...
October 18, 2017: Nano Letters
Katri Avarmaa, Simon Yliaho, Pekka Taskinen
The recycling and recovery of valuable metals from waste materials is one of the key issues in maintaining the sustainability of base and rare metals. Especially WEEE (Waste Electric and Electronic Equipment) can be considered as a high potential resource for a number of valuable and critical metals like gallium, germanium and indium. During the mechanical processing of WEEE, these metals are primary separated into the non-ferrous scrap fractions, including copper fraction. As a consequence, the behavior of these valuable metals and the possibility of their recycling in secondary copper smelting are of great interest...
October 11, 2017: Waste Management
J Riffaud, P Cassette, D Lacour, V Lourenço, I Tartès, M A Kellett, M Corbel, M-C Lépy, C Domergue, C Destouches, H Carcreff, O Vigneau
A new experiment was designed to measure the photon emission intensities in the decay of (103m)Rh. The rhodium samples were activated in the ISIS experimental nuclear reactor at CEA Saclay. The procedure includes an absolute activity measurement by liquid scintillation counting using the Triple-to-Double Coincidence Ratio method, followed by X-ray spectrometry using a high-purity germanium detector to determine the photon emission intensities. The new result (IX = 0.0825 (17)) is derived with a significant reduction of the uncertainty...
October 4, 2017: Applied Radiation and Isotopes
Fei Tuo, Jing Zhang, Wenhong Li, Shuaimo Yao, Qiang Zhou, Zeshu Li
Activity concentrations of (238)U, (226)Ra, (228)Ra, (137)Cs and (40)K in 64 mushroom samples collected in China from Yunnan, Fujian and Heilongjiang Provinces, were measured. Gamma-ray emissions were determined by using high-purity germanium (HPGe) γ spectrometry. The range of concentrations (Bq kg(-1) dry weight) for (238)U, (226)Ra, (228)Ra, (137)Cs and (40)K in all investigated mushroom samples were from 0.12 to 12, 0.05 to 7.5, 0.14 to 14, MDC(<0.01) to 339, and 396 to 1880, respectively. Activity concentrations of (137)Cs in mushrooms showed some variation between species sampled at the same site...
October 11, 2017: Journal of Environmental Radioactivity
Tabitha Amollo, Gene Tessema, Vincent O Nyamori
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...
October 11, 2017: Nanotechnology
Desmond Campbell, Todd Peterson
High-Purity Germanium (HPGe) gamma cameras are an emerging technology for Molecular Breast Imaging (MBI) due to their 2D lateral spatial resolution, depth-of-interaction (DOI) estimation, and superb energy resolution. In this simulation study, we investigate the potential imaging performance of an opposing view dual-head HPGe breast imaging system using a synthetic-projection technique, which utilizes DOI data with varying degrees of overlap in an iterative OSEM reconstruction algorithm to create 3D images from which new 2D projections are then created...
September 2017: IEEE transactions on radiation and plasma medical sciences
Dong Bian, Weirui Zhou, Jiuxu Deng, Yang Liu, Wenting Li, Xiao Chu, Peng Xiu, Hong Cai, Yuhui Kou, Baoguo Jiang, Yufeng Zheng
From the perspective of element biosafety and dietetics, the ideal alloying elements for magnesium should be those which are essential to or naturally presented in human body. Element germanium is a unique metalloid in the carbon group, chemically similar to its group neighbors, Si and Sn. It is a dietary trace element that naturally presents in human body. Physiological role of Ge is still unanswered, but it might be necessary to ensure normal functioning of the body. In present study, novel magnesium alloys with dietary trace element Ge were developed...
October 4, 2017: Acta Biomaterialia
A A Qureshi, S Manzoor, H Younis, K H Shah, T Ahmed
Natural radioactivity was measured in Bunair Granite using high purity germanium gamma-ray spectrometer and compared to world's granites and building materials to access its suitability for the construction purpose. Average gamma-activities of 226Ra, 232Th and 40K were found to be 52.41, 58.41 and 1130.12 Bq kg-1, respectively. The Indoor and outdoor radiation indices including excessive life-time cancer risk (ELCR) were calculated. The average indoor ELCR was estimated as 3.49 × 10-3. The average outdoor ELCR was assessed as 0...
July 20, 2017: Radiation Protection Dosimetry
Dalal A Aloraini, Gharam A Alharshan, Aljawharah H Almuqrin, Hanan Al-Ghamdi, Khaled M El-Azony
Twenty-six brands of canned tuna and sardines imported from several countries in Southeast Asia to consume in the KSA. All samples were prepared and analyzed by using a High Pure Germanium Detector of 40% efficiency. Natural radionuclides 40K, 238U (226Ra) and 232Th(228Ra) series were observed with a varying range in all analyzed samples. The values found to be 192.3 ± 14.6, 1.5 ± 0.8 and 1.0 ± 0.6 Bq kg-1 for canned tuna and 219.8 ± 15.8, 0.37 ± 0.3 and 1.2 ± 0.3 Bq kg-1 for canned sardines, respectively...
July 14, 2017: Radiation Protection Dosimetry
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