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Hyo-Suk Kim, Eun Ae Jung, Seong Ho Han, Jeong Hwan Han, Bo Keun Park, Chang Gyoun Kim, Taek-Mo Chung
New germanium chalcogenide precursors, S═Ge(dmamp)2 (3), S═Ge(dmampS)2 (4), Se═Ge(dmamp)2 (5), Se═Ge(dmampS)2 (6), Te═Ge(dmamp)2 (7), and Te═Ge(dmampS)2 (8), were synthesized from Ge(dmamp)2 (1) and Ge(dmampS)2 (2) using sulfur, selenium, and tellurium powders (dmamp = 1-dimethylamino-2-methyl-2-propanolate, dmampS = 1-dimethylamino-2-methylpropane-2-thiolate). Complexes 1 and 2 were synthesized from metathesis reactions of GeCl2·dioxane with 2 equiv of aminoalkoxide or aminothiolate ligands. Thermogravimetric analysis of complex 1 displayed good thermal stability and volatility...
March 22, 2017: Inorganic Chemistry
Martin E Keillor, C E Aalseth, I J Arnquist, T A Eggemeyer, E S Fuller, B D Glasgow, E W Hoppe, S M Morley, A W Myers, J L Orrell, C T Overman, A Seifert, S M Shaff, K S Thommasson
Low-background lead for radiation measurement shielding is often assayed for (210)Pb to ensure acceptable backgrounds. Samples of lead assayed with a germanium spectrometer calibrated for bremsstrahlung-based assay of (210)Pb provide a view into the (210)Pb content of commercial lead in the U.S. (other than stockpiled Doe Run lead). Results suggest that the loss of lead smelting in the U.S. has eliminated the traditional supply of "low background" lead (~30Bqkg(-1)), and indicate current commercial supplies contain roughly an order of magnitude higher (210)Pb levels...
March 3, 2017: Applied Radiation and Isotopes
Brianna J Mount, Keenan J Thomas, Kelsey C Oliver-Mallory, Kevin T Lesko, Richard W Schnee, Reyco Henning, Ryan F MacLellan, Marcelo B B Guerra, Matthew Busch, Cabot-Ann D Christofferson, J F Wilkerson, Wenqin Xu, Dongming Mei
The Black Hills State University Underground Campus (BHUC) houses a low background counting facility on the 4850' level of the Sanford Underground Research Facility. There are currently four ultra-low background, high-purity germanium detectors installed in the BHUC and it is anticipated four more detectors will be installed within a year. In total, the BHUC will be able to accommodate up to twelve detectors with space inside a class 1000 cleanroom, an automated liquid nitrogen fill system, on-site personnel assistance and other required utilities...
February 16, 2017: Applied Radiation and Isotopes
Dechun Zhou, Xuemei Bai, Hang Zhou
Ho(3+)/Tm(3+) co-doped 50TeO2-25GeO2-3WO3-5La2O3-3Nb2O5-5Li2O-9BaF2 glass fiber is prepared with the rod-tube drawing method of 15 μm core diameter and 125 μm inner cladding diameter applied in the 2.0 μm-infrared laser. The 2.0 μm luminescence properties of the core glass are researched and the fluorescence intensity variation for different Tm(3+) doping concentration is systematically analyzed. The results show that the 2.0 μm luminescence of Ho(3+) is greatly influenced by the doping concentration ratio of Ho(3+) to Tm(3+) and that the maximum fluorescence intensity of the core glass can be obtained and its emission cross section can reach 0...
March 17, 2017: Scientific Reports
Jacob T Held, Samuel Duncan, K Andre Mkhoyan
Quantitative ADF-STEM imaging paired with image simulations has proven to be a powerful technique for determining the three dimensional location of substitutionally doped atoms in thin films. Expansion of this technique to lightly-doped nanocrystals requires an understanding of the influence of specimen mistilt on dopant visibility due to the difficulty of accurate orientation determination in such systems as well as crystal movement under the beam. In this study, the effects of specimen mistilt on ADF-STEM imaging are evaluated using germanium-doped silicon nanocrystals as model systems...
March 7, 2017: Ultramicroscopy
Igor V Korobeinikov, Natalia V Morozova, Vladimir V Shchennikov, Sergey V Ovsyannikov
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...
March 14, 2017: Scientific Reports
Sana Sadeddine, Hanna Enriquez, Azzedine Bendounan, Pranab Kumar Das, Ivana Vobornik, Abdelkader Kara, Andrew J Mayne, Fausto Sirotti, Gérald Dujardin, Hamid Oughaddou
The remarkable properties of graphene stem from its two-dimensional (2D) structure, with a linear dispersion of the electronic states at the corners of the Brillouin zone (BZ) forming a Dirac cone. Since then, other 2D materials have been suggested based on boron, silicon, germanium, phosphorus, tin, and metal di-chalcogenides. Here, we present an experimental investigation of a single silicon layer on Au(111) using low energy electron diffraction (LEED), high resolution angle-resolved photoemission spectroscopy (HR-ARPES), and scanning tunneling microscopy (STM)...
March 10, 2017: Scientific Reports
I Bandac, S Borjabad, A Ianni, R Nuñez-Lagos, C Pérez, S Rodríguez, J A Villar
To support the construction of experiments at the Laboratorio Subterráneo de Canfranc (LSC) in Spain, an Ultra-Low Background Service (ULBS) and a Copper Electroforming Service (CES) were created. The measurement technique employed at the ULBS is gamma spectroscopy with high purity germanium (HPGe) detectors. A new anti-radon system is being implemented. The main goal of CES is to obtain high-purity copper pieces. A new electroforming set-up inside LSC underground clean room is planned. Radon and environmental measurements at the LSC are presented...
March 4, 2017: Applied Radiation and Isotopes
Yoshiyuki Mizuhata, Shiori Fujimori, Takahiro Sasamori, Norihiro Tokitoh
Reduction of the stable germabenzene, 1-Tbt-2-tert-butyl-germabenzene (Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl), with KC8 resulted in the formation of 2-tert-butylgermabenzenylpotassium, that is, the germanium analogue of phenylpotassium, under concomitant elimination of the aryl group from the Ge atom. Under an inert atmosphere, this germabenzenylpotassium could be isolated in the form of stable yellow crystals. In the crystalline state, as well as in solution, the germabenzenyl moiety adopts a monomeric form, even though the X-ray diffraction analysis suggests the presence of highly reactive Ge=C double bonds...
March 8, 2017: Angewandte Chemie
Tiffany Mélanie Beaumont, Pedro Caldeira Ideias, Maeva Rimlinger, David Broggio, Didier Franck
In the case of a nuclear reactor accident the release contains a high proportion of iodine-131 that can be inhaled or ingested by members of the public. Iodine-131 is naturally retained in the thyroid and increases the thyroid cancer risk. Since the radiation induced thyroid cancer risk is greater for children than for adults, the thyroid dose to children should be assessed as accurately as possible. For that purpose direct measurements should be carried out with age-specific calibration factors but, currently, there is no age-specific thyroid phantoms allowing a robust measurement protocol...
March 7, 2017: Physics in Medicine and Biology
S M El-Bahi, A Sroor, Gehan Y Mohamed, N S El-Gendy
In this study, the activity concentrations of the natural radionuclides in phosphate rocks and its products were measured using a high- purity germanium detector (HPGe). The obtained activity results show remarkable wide variation in the radioactive contents for the different phosphate samples. The average activity concentration of (235)U, (238)U, (226)Ra, (232)Th and (40)K was found as (45, 1031, 786, 85 and 765Bq/kg) for phosphate rocks, (28, 1234, 457, 123 and 819Bq/kg) for phosphate fertilizers, (47, 663, 550, 79 and 870Bq/kg) for phosphogypsum and (25, 543, 409, 54 and 897Bq/kg) for single super phosphate respectively...
February 21, 2017: Applied Radiation and Isotopes
Christian Nitsch, Marcel Gerhardt, Claus Gößling, Kevin Kröninger
The Dortmund Low Background Facility is a germanium gamma-ray spectrometry laboratory situated above ground. A massive artificial shielding, corresponding to 10m of water equivalent in combination with an active muon veto results in a background level comparable to laboratories situated underground. Due to the recent completion of the muon veto, the background is lowered by 20% compared to previously reported values (Gastrich et al., 2016). Additionally, Monte Carlo simulations of the cosmic muon induced components of the background spectrum are described...
February 27, 2017: Applied Radiation and Isotopes
Akihito Konishi, Koichi Nakaoka, Hideto Nakajima, Kouji Chiba, Akio Baba, Makoto Yasuda
Cage-shaped borates tethered by heavier group 14 elements (Si or Ge) were synthesized. These possess an intramolecularly transannular pπ-σ* interaction between the boron center and the tethered Si/Ge atom, which allows the precise tuning of their Lewis acidity. The Lewis acidity was investigated via the ligand exchange reaction rate and IR measurements with the help of theoretical calculation. The synthesized borates exhibited catalytic activity. This study demonstrated the effectiveness of the direct orbital perturbation of a metal center via space interaction during the fine-tuning of Lewis acidity...
March 2, 2017: Chemistry: a European Journal
Yu-Liang Shan, Bi-Xiang Leong, Hong-Wei Xi, Rakesh Ganguly, Yongxin Li, Kok Hwa Lim, Cheuk-Wai So
The coordination chemistry of an amidinato silylene and germylene toward group 14 element(ii) halides is described. The reaction of the amidinato silicon(ii) amide [LSiN(SiMe3)2] (1, L = PhC(NtBu)2) with SnCl2 and PbBr2 afforded the amidinato silylene-dichlorostannylene and -dibromoplumbylene adducts [L{(Me3Si)2N}SiEX2] (E = Sn, X = Cl (2); E = Pb, X = Br (3)), respectively, in which there is a lone pair of electrons on the Sn(ii) and Pb(ii) atoms. X-ray crystallography, NMR spectroscopy and theoretical studies show conclusively that the Si(ii)-E(ii) bonds are donor-acceptor interactions...
March 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Won-Jae Joo, Jae-Hyun Lee, Yamujin Jang, Seog-Gyun Kang, Young-Nam Kwon, Jaegwan Chung, Sangyeob Lee, Changhyun Kim, Tae-Hoon Kim, Cheol-Woong Yang, Un Jeong Kim, Byoung Lyong Choi, Dongmok Whang, Sung-Woo Hwang
Rapid progress in two-dimensional (2D) crystalline materials has recently enabled a range of device possibilities. These possibilities may be further expanded through the development of advanced 2D glass materials. Zachariasen carbon monolayer, a novel amorphous 2D carbon allotrope, was successfully synthesized on germanium surface. The one-atom-thick continuous amorphous layer, in which the in-plane carbon network was fully sp(2)-hybridized, was achieved at high temperatures (>900°C) and a controlled growth rate...
February 2017: Science Advances
Long Li, Guang Xu, Hua Shao, Zhi-Hu Zhang, Xing-Fu Pan, Jin-Ye Li
Trace elements, including zinc (Zn) and germanium (Ge), are essential for health; deficiency or excess levels of trace elements results is harmful. As a result of industrial and agricultural production, Pb widely exists in people's living environment. It is absorbed mainly through the respiratory and digestive tracts, producing systemic harm. Reference values for a normal, healthy population are necessary for health assessment, prevention and treatment of related diseases, and evaluation of occupational exposures...
February 24, 2017: International Journal of Environmental Research and Public Health
Mondo Izawa, Taeyeon Kim, Shin-Ichiro Ishida, Takayuki Tanaka, Tadashi Mori, Dongho Kim, Atsuhiro Osuka
[28]Hexaphyrin Ge(IV) and Sn(IV) complexes were synthesized in high yields by reactions of [28]hexaphyrin with GeCl4 or SnCl4 in the presence of triethylamine. Both complexes display distinct 28π Möbius aromatic character and possess a trigonal bipyramidal geometry at the central Ge(IV) or Sn(IV) atom. The equatorial hydroxy group of the Ge(IV) complex was smoothly exchanged with neutral nucleophiles, such as phenol derivatives and thiophenol, with retention of configuration. In the Sn(IV) complex, intersystem crossing to the T1  state is remarkably enhanced owing to the effective heavy-atom effect, thus allowing the formation of the T1  state in high yield...
February 28, 2017: Angewandte Chemie
H Ishizu, T Yamada
When calibrating absolute peak efficiency and total efficiency functions for high efficient germanium detectors, single gamma-emitting nuclides are used in general to avoid coincidence summing effects. As another approach, Blaauw developed calibration technique using multiple gamma-emitting nuclides with least-square technique (Blaauw, 1993; Blaauw and Gelsema, 2003). In the present study, we tried to calibrate efficiency functions of a well-type germanium detector based on Blaauw's approach using a home-made iteration calculation algorithm with the "Solver" add-in in Excel™...
February 21, 2017: Applied Radiation and Isotopes
Yun Tu, Lin Ye, Shao-Ping Zhou, Shan-Tung Tu
Local strain measurements are considered as an effective method for structural health monitoring of high-temperature components, which require accurate, reliable and durable sensors. To develop strain sensors that can be used in higher temperature environments, an improved metal-packaged strain sensor based on a regenerated fiber Bragg grating (RFBG) fabricated in hydrogen (H₂)-loaded boron-germanium (B-Ge) co-doped photosensitive fiber is developed using the process of combining magnetron sputtering and electroplating, addressing the limitation of mechanical strength degradation of silica optical fibers after annealing at a high temperature for regeneration...
February 23, 2017: Sensors
Yuzhong Wang, Hunter P Hickox, Pingrong Wei, Gregory H Robinson
While the 1 : 1 reaction of C4-trichlorosilyl-functionalized N-heterocyclic carbene (NHC) (2) with [(η(5)-C5H4Li)2Fe]3[TMEDA]2 (3) gives C4-sila[1]ferrocenophane-substituted NHC (4), C4-ferrocenylsilyl-bridged bis-NHC (6) is synthesized by combining 3 with C4-chlorodimethylsilyl-functionalized NHC (5) in a 1 : 2 ratio, (compound 5 is prepared by reaction of the anionic N-heterocyclic dicarbene (NHDC) [:C{[N(2,6-Pr(i)2C6H3)]2CHCLi}]n (1) with Me2SiCl2). In addition, ligand 4- and 6-based GeCl2 complexes (7 and 8) are also synthesized...
February 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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