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Germanium and other brittle single crystal materials can be diamond turned with negative rake angle tools, but to maintain surface integrity parameters are typically chosen conservatively. This work describes experiments performed on (100)Ge crystal samples that support a recent scientific finding: increasing the surface speed in diamond turning of germanium improves surface integrity. Materials are machined on a modern ultraprecision diamond turning machine at constant surface speed and constant feed per revolution keeping both the geometric character and the material flow dynamics constant during machining. Forces are measured in the experiments at cutting speeds ranging from 0.2 m/s to 10 m/s. Surface roughness of the machined surfaces was characterized using coherence scanning interferometry and surface analysis. The key findings of the work are (a) force and specific forces decrease by approximately a factor of 2 over the cutting speed range and (b) surface damage substantively decreases with cutting speed. This is correlated to the behavior of the cutting forces during machining and the chip geometry. The findings indicate that higher material removal rates can be obtained in diamond turning of germanium and that this increase in material remove rates also improves surface integrity. [ABSTRACT FROM AUTHOR]

The critical size for the formation of a Ta 2 -endohedral germanium cage-like structure is determined to be Ta 2 Ge 18 -, characterized by a C 6v symmetric Ta 2 -unit-encapsulated tubular structure composed of three Ge 6 hexagons. Additionally, Ta 2 Ge 20 - and Ta 2 Ge 20 clusters display a C 2v symmetric Ge-bicapped Ta 2 -unit-encapsulated tubular structure. [Display omitted] • Critical size determination (n = 18) for Ta 2 -endohedral germanium cage-like structure formation. • Prism-based geometries with central Ta–Ta bonding axis in Ta 2 Ge n -/0 clusters. • Ta 2 Ge 18 - has a C 6v symmetric Ta 2 -unit-encapsulated tubular structure composed of three Ge 6 hexagons. • Both Ta 2 Ge 20 - and Ta 2 Ge 20 have a C 2v symmetric Ge-bicapped Ta 2 -unit-encapsulated tubular structure. This study explores the structural evolution and electronic properties of T Ta 2 Ge n - and Ta 2 Ge n (n = 16–22) clusters using the ABCluster global search algorithm and DFT calculations. The critical size for the formation of a Ta 2 -endohedral germanium cage-like structure is n = 18. The analysis shows a preference for high coordination sites for the two Ta atoms, maintaining proximity to the Ge n frameworks. As a result, the global minima of Ta 2 Ge n -/0 clusters exhibit prism-based geometries with a central Ta–Ta bonding axis interacting with surrounding Ge atoms. [ABSTRACT FROM AUTHOR]

Thermodynamic calculations were performed to determine the optimal conditions for the growth of germanium epitaxial layers from a Ge-Sn solution (system) to a germanium substrate. The determination of the optimal conditions was based on the change in the Gibbs energy values of the system during the crystallization process and the size of the crystal-forming nanoclusters. Based on the results obtained, we determined the optimal conditions for obtaining low-dislocation, crystalline perfect germanium epitaxial layers from a liquid tin solution, and recommended starting the crystallization process at 923 K and finishing at 800 K. When the temperature drops below 800 K, the formation of Ge1-xSnx epitaxial layers from the Ge-Sn solution was observed. [ABSTRACT FROM AUTHOR]

High octane gasoline and aromatics, such as benzene, toluene, and xylenes, are both produced by the catalytic reforming of naphtha, being aromatics crucial building blocks in the chemical industry. Competing reactions occurring concurrently and catalyst deactivation under specific operating conditions make catalytic reforming of naphtha a very complicated process. This review focuses on the catalytic naphtha reforming process for aromatics production and makes special emphasis on reforming catalysts (evolution and recent novelties, as well as their deactivation, regeneration, and reactivation processes). Various aspects of the catalytic reforming process, such as the major reforming reactions carried out during the reforming process, types of industrial reforming processes, characteristics of the reviewed reforming processes, and the reaction parameters and their effect on the catalytic reforming process, are also considered in order to establish the context. Reforming catalysts are bifunctional, while some reactions just require the Pt site or the acid function to complete, others require both of these types of sites. Platinum is generally combined with one or two metals, such as Re, Ir, Sn, or Ge. The catalyst's acidic function is determined by chlorine, which also contributes to a high dispersion of the metallic phase. Research into naphtha reforming catalysts is looking for ways to improve aromatics yield and catalyst life. It has been noted that low dehydrogenating capacity and high hydrogenolytic capacity, both of which are provided by Pt, as well as low polymerization capacity, which is provided by the strong acid sites in the support, are the characteristics that make a catalyst stable as a result of the lesser formation of coke. Significant differences in the catalysts' basic composition have not been documented because bi- and trimetallic catalysts are still actively researched due to the complexity of their chemistry, with the identification of the wide variety of sites present within them and the understanding of their chemistry being of utmost importance. Even so, some innovation has occurred in recent years, among which are: non-noble metal reforming catalysts based on metal carbides, metal zeolite composite catalysts, the use of metals (In and Ga) other than those commonly used, and Ce3+-modified zeolites as support. [Display omitted] • High octane gasoline and aromatics, can be produced by the catalytic reforming of naphtha. • Catalytic reforming of naphtha is a very complicated process due to the catalyst deactivation. • Research into naphtha reforming catalysts is looking to improve aromatics yield and catalyst life. • Naphtha catalytic innovation is based on metal carbides, In,Ga,Ce modified zeolites and F promotion. [ABSTRACT FROM AUTHOR]

The resulting surface integrity of (100)Ge subjected to off-axis single point diamond turning was investigated. Feedrate was varied using 9 and 20 μm/rev at 10 μm nominal depth of cut. Surface topography was measured with coherence scanning interferometry and atomic force microscopy. The resulting near surface lattice disorder was investigated with channeling Rutherford Backscattering Spectrometry and Raman Spectroscopy. Measured near surface lattice disorder was quantified in terms of equivalent amorphous layer thickness and minimum channeling yield. A comparison of the resulting surface integrity was made with surfaces created by chemomechanical polishing and magnetorheological finishing. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rare Metal Materials & Engineering is the property of Northwest Institute for Nonferrous Metal Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work we investigate a structure based on p-doped Ge/SiGe asymmetric-coupled quantum wells (ACQW) that enables the second harmonic generation in SiGe waveguide by double-resonant intersubband transitions (ISBTs). These transitions lead to χ(2) coefficients in the range 104-105 pm/V, significantly higher compared to the one of conventional nonlinear materials. We developed a model for the integration of Quantum Wells (QWs) into the active region of the waveguide through an adiabatic taper. Furthermore, we modelled the second harmonic (SH) conversion efficiency as a function of the propagation length, under both non-phase matching and phase-matching conditions. Our work demonstrates that the SiGe ACQWs can be used in spectral ranges not covered by the majority of conventional non-linear crystals, while allowing for the ready-integration with the CMOS technologies. • Theoretical investigation of second harmonic generation in waveguide integrated Ge quantum wells • Modelling of an adiabatic taper to transfer optical mode with minimal losses. • Second-Harmonic conversion efficiencies up to 2.91%/W in the mid-infrared. [ABSTRACT FROM AUTHOR]

Large amount of coal ash is produced as industrial waste during the electricity generation through the combustion of lignite. Toxic elements arsenic exists in the coal ash, which hinders the subsequent recycling processes. Moreover, coal ash could be recycled further to retrieve scattered metals germanium and tungsten. It is believed that traditional recycling methods present barriers to scaled application, especially serious secondary pollution, such as toxic residue and waste liquid. In this work, a novel sequential vacuum distillation with disulphide method is proposed to separate arsenic, germanium and tungsten from coal ash. First, arsenic can be volatilized completely out of the reaction system at temperatures below 550 °C. Subsequently, Ge and W volatilized in the form of sulfide in the presence of Na 2 S 2 O 3. The optimal condition was 1050 °C, the mass ratio of 0.6 with reaction a pressure of 1 Pa and a time duration of 120 min demonstrated the best evaporation ratio. For coal fly ash, chemical species As 2 S 3 , GeS, and WO x (x < 3)/WS 2 were the main condensed products. For coal bottom ash, As 2 S 3 , GeS, and WO 3 /WS 2 were dominant chemical components. Mechanisms for the process of release and evaporation of As, Ge, and W from coal ash, vacuum reaction, evaporation, and condensation were analyzed. In summary, the vacuum distillation method deserves to be further developed as it provides an eco-friendly method to recycle coal ash. [Display omitted] • An environment-friendly sequential vacuum distillation method is proposed. • Mixed sulfide reagents are used to remove As and recycle Ge, and W step by step. • As 2 S 3 , GeS, and WO x (x < 3)/WS 2 are the main condensed products in ash. • Mechanisms of release and evaporation processes of As, Ge, and W are analyzed. • Residues are not a hazardous material and can be further recycled. [ABSTRACT FROM AUTHOR]

[Display omitted] • The metallic nature of germanium allotropes in the form of prismanes is predicted. • The metallicity of germanium prismanes conserves under mechanical strain. • The studied properties of electron transport confirm the presence of ballistic conductivity in 6 G 0 and 7 G 0 for Ge 5 - and Ge 6 -prismanes, respectively. Guided by Density Functional Theory within the bounds of GGA/PBE theory, we study the electronic, energy, mechanical and ballistic conductivity of germanium [n,m]-prismanes. The prismatic structure is a cylinder, with a m -vertices polygon (germanium ring) at the foot and an n -number of such polygons along the growth direction of the nanotube. As depicted, the finite prismanes reduce their band gap with an increase in the number of rings and periodic systems have metallic conductivity. It is established that metallic properties are resistant to the stress applied along the main axis of the prismanes. [ABSTRACT FROM AUTHOR]

• A novel persimmon tannin/graphene oxide composite by one-step crosslinking method was prepared. • This method resolved the solidification problem of persimmon tannin and improved the hydrophilicity of GO. • The composite showed superior adsorption capacity towards Ge(IV). Herein, a new persimmon tannin/graphene oxide (GO-PT-6Glu) composite was fabricated through one-step cross-linking method. The as-prepared GO-PT-6Glu has substantial phenolic hydroxyl groups (up to 5.23 mmol g−1) by introducing water-soluble PT (up to 5.50 mmol g−1) on the GO, which provides the opportunity to use it as an adsorption material to recover germanium. The GO-PT-6Glu was then used to adsorb germanium from aqueous solution and showed the highest than among currently reported adsorption capacity (117.38 mg g−1). Simultaneously, it exhibits excellent cycle performance to adsorb germanium still with a high adsorption efficiency (up to 81.42%) after 5 adsorption–desorption cycles. More importantly, the GO-PT-6Glu showed superior selectivity towards Ge(IV) as compared to As(III) (Cl−/SO 4 2−/PO 4 3−), in spite of the concentration of As(III) (Cl−/SO 4 2−/PO 4 3−) was 100 times higher than that of Ge(IV). Taking advantages of its low cost, selective adsorption, as well as environmental protection and high adsorption, the GO-PT-6Glu is expected to be the most promising material in recovery of Ge(IV) from water containing As(III). [ABSTRACT FROM AUTHOR]

This paper aims to investigate the mechanism of stress mitigation in micrometer (μm) sized Selenium (Se)-doped Germanium (Ge) electrode, which includes a self-forming inactive Li-Ge-Se network enveloping multiple nanometer-sized crystalline Ge (c-Ge) particles. Considering the electrode system contains multiply active particles, models based on single-particle are unable to fully understand elusive underpinning mechanism. Hence, a phase-field model is employed to investigate the effect of the Li-Ge-Se network on the particle-particle interaction, and the stress variation of the electrode upon lithiation. The amorphous Li-Ge-Se network provides an effective Li diffusion path for inter-particle diffusion, reducing stress difference between the surfaces of neighboring particles. Furthermore, the constraint between the adjacent particles induces a higher compressive stress at the reaction front impeding the mobile Li insertion during lithiation. Though small c-Ge nano-particle in the Ge0.9Se0.1 microparticle is lithiated quickly, the compressive stress is generated at its center for stress equilibrim causing more retardation effect. Meanwhile, the size difference between adjacent particles increases the principle and shear stresses in the inactive Li-Ge-Se, which could potentially lead to mechanical failure and debonding of the amorphous network. We believe that the results of this investigation can shed some light on the optimization design of electrodes. [ABSTRACT FROM AUTHOR]

Integrated geological and geochemical studies were performed for lignite from the Yenisei middle reaches, represented by carbonized fragments of trees with high germanium contents. Geochemical characteristics of terrigenous sediments with Ge-bearing lignite are determined. The chemical and mineral compositions, textures, and structures of carbonized wood fragments were studied. Scanning of individual cross sections of lignite fragments has revealed a regular distribution of germanium and impurity elements. Consistent patterns of the formation of Ge-containing lignites have been established, as well as the processes of their posthydrothermal transformation, which led to the impoverishment of the primary contents of the valuable component and to the input of a number of impurity elements. The latter formed rims over the lignite fragments and microveinlets with sulfide mineralization. The hypothesis has been put forward that germanium mineralization formed in lignites of the Kas basin, in particular, the Serchanskoe deposit. [ABSTRACT FROM AUTHOR]

Gamma spectroscopy was performed to determine the concentrations of 226 Ra, 232 Th and 40 K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg −1 for 226 Ra, 85.67 Bq kg −1 for 232 Th and 425.72 Bq kg −1 for 40 K. The average activity concentration of 232 Th and 40 K are slightly higher and 226 Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Ra eq ) Absorbed Gamma Dose Rate (D R ), Annual Effective Dose Rate (H R ), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE) , Internal Hazard Index (H in ) and External Hazard index (H ex ) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides. [ABSTRACT FROM AUTHOR]

The electrodeposition of germanium antimony telluride (GST) alloys from a single non-aqueous plating bath based on tetrabutylammonium chlorometallate precursors is presented. The system provides a case-study for plating bath optimization in order to produce complex functional materials. GST deposits in the amorphous phase and the film composition and morphology can be readily adjusted by tuning the three precursor concentrations and the electrodeposition potential. Adjustment of the precursor concentrations allows the preparation of deposits ranging from the binaries (GeSb, GeTe, Sb2 Te3) to ternaries with a wide range of compositions, including the standard Ge2Sb2Te5 composition - more commonly known as GST-225 - which is widely used in the solid state memory industry. In this paper we present a detailed study discussing the complex interplay between the deposition of germanium, antimony and tellurium and how adjusting the concentrations of their chlorometallates allows control over the composition and also the morphology of the deposits. We also highlight the benefits that arise from the wide separation in the deposition potentials for the three precursors, and in particular the ability to control the composition through modulation of the deposition potential. [ABSTRACT FROM AUTHOR]

A GeCl2-mediated addition reaction of α-(N-phthaloylamino) allylic stannane to aldehydes was achieved to give 1,2-amino alcohol derivatives in high anti-selectivity. Various types of aromatic and aliphatic aldehydes were applicable. The synthesized N-phthaloylamino alcohols were smoothly transformed to aminoalcohols by conventional methods with no loss of stereochemistry. [ABSTRACT FROM AUTHOR]

Planar tetracoordinate silicon/germanium (ptSi and ptGe) clusters, D 4h SiNi 4 Cl 4 and GeNi 4 Cl 4 , are used to construct three series of low-dimensional ptSi/ptGe nanostructures: nanoribbon complexes X n Ni 2 n +2 Cl 2 n +2 (X = Si, Ge; n  = 1–8) and nanotube complexes Si n Ni 2 n Cl 2 n ( n  = 11–14), denoted as 1 – 8 , 1′ − 8′ , and 9 – 12 , respectively. Density-functional theory (DFT) calculations indicate that all species are true minimum on their potential energy surfaces. Chemical integrity of ptSi/ptGe is maintained in the nanostructures. The ptSi based nanoribbons undergo out-of-plane distortion, whereas ptGe based ones are perfectly planar. This observation is attributed to steric effects of Cl ligands in the former species. A chemical bonding model is proposed for D 4h SiNi 4 Cl 4 and GeNi 4 Cl 4 clusters, featuring π and σ aromaticity. Aromaticity appears to be preserved for ptSi/ptGe centers in the nanoribbon complexes. [ABSTRACT FROM AUTHOR]

Ferrocenyl derivatives with perfluorinated organometallic fragments are prospective sensitizers for photovoltaic devices which can provide higher stability and resistance to oxidation in comparison with the known analogs. For the development of the photovoltaic devices based on such molecules, the estimates of probabilities of photoinduced electron transfer both inside the molecule and from the molecule to the internal semiconductor electrode are required. In this work, the structural, electronic, spectral and radiative parameters of trialkylgermyl (alkyl = Me, n -C 3 H 7 , CF 3 , n -C 3 F 7 ) derivatives of 4,4′-diethynylbiphenyl containing ferrocenyl donor group are considered. The spectral and radiative parameters of these compounds were calculated using the TD-DFT theory with the B3LYP, PBE0, BHandHLYP и CAM-B3LYP functionals. For all the molecules, the probabilities of photoinduced electron transfer to the outer molecular fragments inside the sensitizer are estimated on the basis of direct analysis of charge redistributions in the excited states. [ABSTRACT FROM AUTHOR]

100 Gbps (4 × 25 Gbps) optical receiver (Rx) module is demonstrated using Germanium (Ge) photodetector (PD) which is fabricated through Silicon-photonics process using 750 ohm-cm of high-resistivity silicon oxide insulator (SOI) wafer. Trans-impedance amplifier (TIA) and Ge PD are packaged with chip-on-board (COB) manner on a printed circuit board (PCB). High speed PCB for the assembly of both electronic and photonic devices in COB package is precisely designed from the material selection to the device footprint layout and transmission line design. The layout on PCB is optimized using high frequency simulation tool of HFSS to minimize RF loss happening in the transmission line and electrical interconnection points of bond wires. Electrical-optical (EO) S-parameter measurement for the Ge PD shows 22 GHz of transmittance (S21) 3dB bandwidth. Photocurrents of the photodetector induced by the optical input power are analyzed for signal integrity both TIA ON and OFF states. Photocurrent changes by the misalignment of the lensed optical fiber coupled to the edge coupler of the Ge PD shows that 3dB misalignment tolerances are 5.5 µm in the longitudinal and around +/-1 µm in the lateral directions. This COB packaging technique of optical Rx module can be applied for the integration and assembly of the optical module of higher data rate of 100 Gbps and beyond. [ABSTRACT FROM AUTHOR]

A Sn-Ge oxide film was deposited on glass using a chemical method that was based on electroless reactions at low temperatures. The film was dark brown and demonstrated catalytic activity that meant that Ni could be deposited onto it in an electroless Ni bath without any catalyzing treatment being required. After annealing, the Sn-Ge oxide film became relatively transparent, and it approached the appearance of bare glass. The morphological and crystal structure of the film was examined using scanning electron microscopy, X-ray diffraction measurements, and atomic force microscopy. We determined there was no change in the morphological structure of the films, and the films were amorphous even if the film was annealed. The composition of the film was characterized using X-ray photoelectron spectroscopy, which indicated that the film contained SnOx (x = 1, 2), and GeOx (x = 1, 2) as a mixture. We tried to apply the Sn-Ge oxide film as an adhesion layer between a plating film of Cu/Ni and a glass substrate, and we found that the peel strength of this layer was about 3-4 N cm-1 after annealing was conducted at 450°C. According to the X-ray photoelectron spectroscopy depth profile, the increase in the adhesion strength was due to atomic inter-diffusion between the Sn-Ge oxide film and the glass substrate. [ABSTRACT FROM AUTHOR]

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. Feasibility of those alloys to be used as orthopaedic implant applications was systematically evaluated. Mg-Ge alloys consisted of α-Mg matrix and eutectic phases (α-Mg + Mg 2 Ge). Mechanical properties of Mg-Ge alloys were comparable to current Mg-Ca, Mg-Zn and Mg-Sr biodegradable metals. As-rolled Mg-3Ge alloy exhibited outstanding corrosion resistance in vitro (0.02 mm/y, electrochemical) with decent corrosion rate in vivo (0.6 mm/y, in rabbit tibia). New bone could directly lay down onto the implant and grew along its surface. After 3 months, bone and implant were closely integrated, indicating well osseointegration being obtained. Generally, this is a pioneering study on the in vitro and in vivo performances of novel Mg-Ge based biodegradable metals, and will benefit the future development of this alloy system. Statement of Significance The ideal alloying elements for magnesium-based biodegradable metals should be those which are essential to or naturally presented in human body. Element germanium is a unique metalloid in the carbon group. It is a dietary trace element that naturally presents in human body. In present study, feasibility of Mg-Ge alloys to be utilized as orthopedic applications was systematically investigated, mainly focusing on the microstructure, mechanical property, corrosion behavior and biocompatibility. Our findings showed that Mg-3Ge alloy exhibited superior corrosion resistance to current Mg-Ca, Mg-Zn and Mg-Sr alloys with favorable biocompatibility. This is a pioneering study on the in vitro & in vivo performances of Mg-Ge biodegradable metals, and will benefit the future development of this alloy system. [ABSTRACT FROM AUTHOR]

Low leaching efficiency of germanium has always been a difficult point hindering the efficient utilization of zinc oxide dust containing germanium. Based on the previous research results that the formation of insoluble Fe 4 Ge 3 O 12 leads to germanium loss in the leaching process, a new process of reduction leaching of zinc oxide dust containing germanium enhanced by ultrasonic and iron powder is proposed. Under optimized conditions, the germanium leaching efficiency can be increased by 9.17%, reaching 93.43%. When leaching, the addition of iron powder can reduce the Fe3+ formed in the leaching process and hinder the formation of insoluble Fe 4 Ge 3 O 12, which can increase the leaching efficiency of germanium by 5.30%. At the same time, strong mechanical action of ultrasonic can fully disperse the iron powder in the leaching system, avoiding the phenomenon of insufficient local reduction. More importantly, the addition of ultrasonic can reduce the dissolved oxygen in the solution system and produce strong reducing hydrogen free radicals (H), strengthening the reduction leaching effect, thus the germanium leaching efficiency is further increased by 3.87%. The research results provide a new method and theoretical guidance for the efficient utilization of zinc oxide dust containing germanium, which is of great significance. [ABSTRACT FROM AUTHOR]

For the first time chloranilic acid was used as a complexing agent in the adsorptive stripping voltammetric method to perform trace determination of germanium. As an example of the proposed procedure the ultra-trace Ge(IV) determination in environmental samples, such as river and lake water samples was carried out. The composition of the supporting electrolyte as well as the influence of accumulation potential and time on the germanium voltammetric signal were verified. The method is based on cathodic adsorptive stripping voltammetry of the Ge(IV)-chloranilic acid complex at a renewable mercury film silver based electrode (Hg(Ag)FE). The calibration graph was linear from 5 × 10-10 to 2 × 10-7 mol L-1 with a detection limit calculated as 1.67 × 10-10 mol L-1 for a deposition time of 30 s. The influence of interfering substances such as foreign ions, EDTA, surfactants and humic substances present in the matrices of natural water samples on the Ge(IV) signal was precisely examined and the satisfying minimization of these interferences was proposed. [ABSTRACT FROM AUTHOR]

With the rapid development of optical fiber communications industry, germanium as main raw materials of optical fiber cables become more important in recent years. Due to the scarcity and importance of germanium, we developing an effective recycling process of recovering germanium metal from waste fiber optic cables. The process was arranged to do pre-treatment, leach the fiber and extract the germanium from silicon. In the leaching step, the concentration of different acid, reaction time and liquid-solid ratio were investigated. At the solvent extraction process, the pH value, concentration of extractant and stripping agents, organic-aqueous ratio and reaction time were considered. In leaching step, germanium and silicon were dissolved in solution by sulfuric acid and hydrofluoric acid. Then, germanium was extracted by Trioctylamine (TOA) to the organic phase and silicon was remained in the aqueous by controlling the conditions. After then, Germanium was then stripped by sodium hydroxide. With the optimal conditions, the recovery of germanium could be up to 99%. After separation, germanium could be recycled to back to the industrial effectively. [ABSTRACT FROM AUTHOR]

Tunnel FET (TFET) has potential applications in the next generation ultra-low power transistor to substitute the conventional FETs. It can offer very steep inverse subthreshold swing slope to maintain a low leakage current, thus it can be very essential for limiting power consumption in MOSFETs. The carriers in TFET transport from source to channel by the band-to-band tunneling (BTBT) mechanisms. To realize high saturation currents of TFET, it critically depends on the transmission probability, TWKB. In indirect semiconductor, such as Si and Ge, the BTBT model is very crucial for designing and predicting the device performance. In this paper, we employed the nonlocal BTBT model applied to three-dimensional Ge-Si heterojunction TFET with gate length 10 nm compare with Si TFET by including quantum effects simulation. The results show that the Ge-Si TFET outperforms Si TFET because of the lower bandgap and larger tunneling windows. BTBT generation rates of Ge-Si TFET are higher than Si TFET in the on-state condition. The highest BTBT generation rates are located in the source and channel junction and its peaks close to the gate dielectric. [ABSTRACT FROM AUTHOR]

The geochemistry of major, trace, rare earth elements (REEs), with special reference to Ge, Li, and Hg in selected Gondwana and Eocene coals, has been studied. Major oxide and trace element ratios have been utilised to compare the tectonic setting, provenance of source rocks, and paleoweathering conditions that prevailed the during formation of these coals. The Gondwana coals have a higher mean mercury and ash content (244.5 μg/kg and 17.2 %, respectively) than the Eocene coals (142.1 μg/kg, 8.9 % respectively). The major oxides, SiO 2 , Fe 2 O 3, and Al 2 O 3, in Gondwana and Eocene coals, are enriched relative to the upper continental crust (UCC), Chinese and American coals. The UCC normalized trace element concentration coefficients of the Gondwana and Eocene coals show enrichment in Ge, Se, Th, Co, Mo, Sn, W, and Li. The mean Ge and Li concentrations (mg/kg) in Gondwana (106.7, 154.7) and Eocene (120.0, 252.6) exceed the corresponding values in world coal (2.2, and 12). The Rajmahal coals have the highest mean Ge concentration (168.8 mg/kg) among the Gondwana coals while Eocene coals from East Jaintia Hills have the highest mean value (343.7 mg/kg). The Gondwana coals have a higher mean As concentration (3.5 mg/kg) in comparison to the Eocene coals (1.9 mg/kg). The mean of the rare earth elements in Gondwana (24.1 mg/kg) is higher than that in Eocene coals (11.3 mg/kg) and these values are less than the World coals (68.5 mg/kg). Both the Gondwana and Eocene coals are enriched in light rare earth elements (LREEs). However, among the Eocene coals, the Meghalayan coals show REE enrichment in comparison to Assam coals. Both the Gondwana and Eocene coals were formed in warm and humid climates under oxic conditions with moderate weathering of the source rocks. • Geochemistry of major, trace, rare earth elements in some Gondwana and Eocene coals studied • The Gondwana coals have a higher mean mercury and ash content than the Eocene coals. • Ge and Li show a high and persistent enrichment in both the Gondwana and the Eocene coals. • The Gondwana and the Eocene coals have lower mean REY concentrations than the World coals. • The Gondwana and the Eocene coals were formed in warm, humid climates under oxic conditions. [ABSTRACT FROM AUTHOR]

Ge NWs have been selectively grown directly on top of the suspended microhotplates, with heater and interdigitated electrodes, via Au catalyzed Vapor Liquid Solid (VLS) mechanism through a low-power consumption CVD-like process. The so-fabricated devices, with a p-type semiconductors behavior, have been characterized towards water vapor in synthetic air, keeping the temperature at 100°C in order to achieve a stable oxide. The results show reproducible responses towards H 2 O. [ABSTRACT FROM AUTHOR]

• Three hydroxyl groups were modified on the surface of TA-TiO 2 -OH by TA. • The maximum adsorption capacity of TA-TiO 2 -OH for Ge(IV) is 122.26 mg·g−1. • Adsorption capacity of TA-TiO 2 -OH was larger than SA-TiO 2 -OH and MA-TiO 2 -OH. • TA-TiO 2 -OH exhibited good adsorption selectivity of Ge at high acidity. To compose an effective adsorbent for water purification, surface functional groups have a critical role in determining the adsorption achievement of metal oxide particles. Herein, the organic acid-functionalized TiO 2 nanoparticles were synthesized by modifying TiO 2 nanoparticles with organic acids contenting different number of hydroxyl groups. The adjustment of the surface hydroxyl functional groups content of functionalized TiO 2 nanoparticles significantly affected the Ge(IV) adsorption capacity. Our results indicate successfully that the obtained tartaric acid (dihydroxysuccinic acid) functionalized TiO 2 (TA-TiO 2 -OH) have more hydroxyl functional groups (up to 4.38 mmol·g−1) and large Ge(IV) adsorption capacity (122.26 mg·g−1) at pH = 3, which are higher than those of the currently reported adsorbents. More importantly, TA-TiO 2 -OH also has a remarkable affinity for Ge(IV) at a Ge(IV) metallurgical simulated solution. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present research, the gamma-emitting radionuclides in beach sands along the coastal regions of the Ordu, Giresun and Trabzon provinces, Turkey have been determined. The natural and anthropogenic radionuclide concentrations of the samples have been measured employing a germanium (HPGe) detector with high resolution and purity. The activity for 238 U, 232 Th, 40 K and 137 Cs of the samples were found to vary in the range from below detection limit (BDL) to 65 Bq·kg − 1 , from BDL to 28 Bq·kg − 1 , from 9 to 1936 Bq·kg − 1 and from BDL to 22 Bq·kg − 1 , respectively. The activity concentrations were compared with those in the literature. The associated radiological hazard indices were estimated, and were compared to the internationally recommended values. The radiological map of beach sand in the surveyed area was imaged. The data presented in the study are crucial since they constitute a baseline for the radiological mapping of the region in the future. [ABSTRACT FROM AUTHOR]

The electron spin resonance (ESR) dating of tills using germanium-doped (Ge) paramagnetic centers in quartz has advantages over other dating techniques, as quartz is common, processing is easy, and the technique has the potential for dating features several hundreds of thousands years old. ESR dating of moraines is based on the supposition that either subglacial comminution or exposure to sunlight resets the signal. However, actual dating suggests that a signal that is initially present cannot be bleached to zero by grinding alone. We found that grinding coarse samples (0.5–1 mm in diameter) to the mean grain size of fine sand (0.125–0.193 mm) reduced the signal intensity to 53–69% of its original value. From the value of the signal difference, one can devise a correction factor for ESR ages of subglacial sediment. Polymineralic grains are commonly present in till. Exposure of them to sunlight for several days can reduce the signal intensity to 7–8% of its original value within 1–2 mm thick of the sediment surface. However, within 5–8 mm of the sediment surface, exposure to sunlight for over one week only reduced the signal intensity to mean plateau values of 42–50% of the initial value. Mixing upper and lower layers of the samples during exposure to sunlight changed the signal intensity. This suggests that the amount of bleaching varies spatially. Sediments initially deposited at the margins of ice caps or ice sheets and subsequently overridden may have been sufficiently exposed to sunlight to allow ESR dating of moraines. The purity of the quartz and the grain size have significant impacts on signal intensity; intensive purification and the use of a uniform fine sand fraction are thus recommended. [ABSTRACT FROM AUTHOR]

A resonant-cavity-enhanced solar cell with a 25 nm thick amorphous germanium nanoabsorber is demonstrated. The device is specifically designed for use as bottom cell in multijunction devices. In this case, instead of relying on broadband absorption, only red light needs to be absorbed in the bottom cell. This allows exploiting the narrow resonance patterns of long Fabry-Pérot cavities to achieve efficient absorption inside the nanoabsorber. It is shown that this approach can only be integrated into multijunction devices when suppressing inter-subcell coherence. To achieve this, the intermediate reflector of the tandem device is textured using electrochemically grown zinc oxide nanorods. [ABSTRACT FROM AUTHOR]

Silicon-based photonic integrated circuits (PICs) operating in the mid-infrared wavelength range are presented. Firstly, it is shown that the operation of the SOI-based waveguide circuits can be pushed beyond the telecom window till a wavelength of 4 μm. Ge-on-Si based PICs are demonstrated for operation beyond 4 μm wavelength. Low-loss waveguides and integrated spectrometers are reported for both the waveguide platforms. We also present our results on efficient thermo-optic phase shifters for germanium waveguide circuits. [ABSTRACT FROM AUTHOR]

Freeform germanium optics produced by single crystal diamond milling are important for infrared (IR) imaging applications. However the mechanics of interrupted cutting of germanium is not fully understood. This paper presents new findings from cutting experiments including: (1) uninterrupted orthogonal cutting and (2) interrupted flycutting of germanium. Forces are measured and the cutting mechanics are correlated with surface and subsurface measurements performed with: (1) atomic force microscopy, (2) confocal Raman spectroscopy, and (3) channeling Rutherford backscattering spectrometry. These fundamental results guide parameter choice for more complex freeform ball milling of optics for IR applications ranging from surveillance to medical imaging. [ABSTRACT FROM AUTHOR]

The heavier phenyl anion analogues, 2-tert-butylgermabenzenyllithium Li+¢1- and sodium Na+¢1-, were synthesized via aryl elimination from the corresponding 1-Tbt-2-tert-butylgermabenenze 3 (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl). The properties of Li+¢1- and Na+¢1- have been elucidated spectroscopically, and structural determination of Na+¢1- was performed using X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

A high performance germanium (Ge) based anode is achieved through an appropriate air annealing post-treatment. Annealed Ge is fabricated by sputtering of Ge onto a stainless steel (SS) current collector and then annealed in air. It shows high specific and volumetric capacities of 1186 mA h g −1 and 5887.4 mA h cm −3 , respectively, at the rate of 812 mA g −1 up to 50 cycles. These specific and volumetric capacities are approximately a factor of 20 higher than those from as-deposited Ge on the SS substrate. In addition, the annealed Ge has a higher initial Coulombic efficiency of 90.8% than the as-deposited Ge of 81%. The improved performance of the annealed Ge can be attributed to the enhanced adhesion of annealed Ge film to SS substrate through interdiffusion at the SS/Ge interface due to the annealing post-treatment. [ABSTRACT FROM AUTHOR]

We report a computational study of the aluminum doped germanium clusters Ge n Al ( n = 1–9). The molecular geometries and electronic structures of the Ge n Al clusters are investigated systematically using quantum calculations at the B3LYP level with the 6-311G(d) basis sets. The growth pattern behaviors, stabilities, electronic properties, and magnetic moments of these clusters are discussed in detail. Obviously different growth patterns appear between small and larger Al-doped germanium clusters, the optimized equilibrium geometries trend to prefer the close-packed configurations for Al-doped germanium clusters up to n = 9. The size dependence of cluster average binding energies per atom ( E b /atom), second-order differences of total energies ( Δ 2 E ), fragmentation energies ( E f ) and HOMO–LUMO gaps of Ge n +1 and Ge n Al ( n = 1–9) clusters are studied. The stability results show that Ge n +1 cluster possess relatively higher stability than Ge n Al cluster. Furthermore, the investigated highest occupied molecular orbital-lowest unoccupied molecular orbital gaps indicate that the Ge n +1 and Ge n Al clusters have different HOMO–LUMO gap. In addition, the calculated vertical ionization potentials and vertical electron affinities confirm the electric properties of Ge n +1 and Ge n Al clusters. Besides, the doping of Al atom also brings the decrease as the cluster sizes increase for atomic magnetic moments ( μ b ). [ABSTRACT FROM AUTHOR]