Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

AbstractMonolayer tungsten disulphide (WS2) is a direct band gap semiconductor which holds promise for a wide range of optoelectronic applications. The large-area growth of WS2 has previously been successfully achieved using a W(CO)6 precursor, however, this is flammable and a potent source of carbon monoxide (CO) upon decomposition. To address this issue, we have developed a process for the wafer-scale growth of monolayer WS2 from a tungsten hexachloride (WCl6) precursor in a commercial cold-wall CVD reactor. In comparison to W(CO)6, WCl6 is less toxic and less reactive and so lends itself better to the large-scale CVD growth of 2D layers. We demonstrate that a post-growth H2S anneal can lead to a dramatic improvement in the optical quality of our films as confirmed by photoluminescence (PL) and Raman measurements. Optimised films exhibit PL exciton emission peaks with full width at half maximum of 51 ± 2 meV, comparable to other state-of-the-art methods. We demonstrate that our WS2 films can be readily transferred from the sapphire growth substrate to a Si/SiO2 target substrate with no detectable degradation in quality using a polystyrene support layer. Our approach represents a promising step towards the industrial-scale fabrication of p-n junctions, photodetectors and transistors based on monolayer WS2.

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DeepMAsED: evaluating the quality of metagenomic assemblies

Bioinformatics ◽

10.1093/bioinformatics/btaa124 ◽

2020 ◽

Vol 36 (10) ◽

pp. 3011-3017 ◽

Cited By ~ 5

Author(s):

Olga Mineeva ◽

Mateo Rojas-Carulla ◽

Ruth E Ley ◽

Bernhard Schölkopf ◽

Nicholas D Youngblut

Keyword(s):

Large Scale ◽

State Of The Art ◽

Ground Truth ◽

Supplementary Information ◽

Learning Approach ◽

Wide Range ◽

Metagenome Assembly ◽

Model Training ◽

Reference Genomes

Abstract Motivation Methodological advances in metagenome assembly are rapidly increasing in the number of published metagenome assemblies. However, identifying misassemblies is challenging due to a lack of closely related reference genomes that can act as pseudo ground truth. Existing reference-free methods are no longer maintained, can make strong assumptions that may not hold across a diversity of research projects, and have not been validated on large-scale metagenome assemblies. Results We present DeepMAsED, a deep learning approach for identifying misassembled contigs without the need for reference genomes. Moreover, we provide an in silico pipeline for generating large-scale, realistic metagenome assemblies for comprehensive model training and testing. DeepMAsED accuracy substantially exceeds the state-of-the-art when applied to large and complex metagenome assemblies. Our model estimates a 1% contig misassembly rate in two recent large-scale metagenome assembly publications. Conclusions DeepMAsED accurately identifies misassemblies in metagenome-assembled contigs from a broad diversity of bacteria and archaea without the need for reference genomes or strong modeling assumptions. Running DeepMAsED is straight-forward, as well as is model re-training with our dataset generation pipeline. Therefore, DeepMAsED is a flexible misassembly classifier that can be applied to a wide range of metagenome assembly projects. Availability and implementation DeepMAsED is available from GitHub at https://github.com/leylabmpi/DeepMAsED. Supplementary information Supplementary data are available at Bioinformatics online.

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Design and Demonstration of Large Scale Cu2O Photocathodes with Metal Grid Structure for Photoelectrochemical Water Splitting

Energies ◽

10.3390/en14217422 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7422

Author(s):

Min-Kyu Son

Keyword(s):

Water Splitting ◽

Large Scale ◽

Grid Structure ◽

Large Area ◽

Intrinsic Conductivity ◽

Metal Grid ◽

Splitting System ◽

Insight Into ◽

Better Than

Upscaling of photoelectrode for a practical photoelectrochemical (PEC) water splitting system is still challenging because the PEC performance of large-scale photoelectrode is significantly low, compared to the lab scale photoelectrode. In an effort to overcome this challenge, sputtered gold (Au) and copper (Cu) grid lines were introduced to improve the PEC performance of large-scale cuprous oxide (Cu2O) photocathode in this work. It was demonstrated that Cu grid lines are more effective than Au grid lines to improve the PEC performance of large-scale Cu2O photocathode because its intrinsic conductivity and quality of grid lines are better than ones containing Au grid lines. As a result, the PEC performance of a 25-cm2 scaled Cu2O photocathode with Cu grid lines was almost double than one without grid lines, resulting in an improved charge transport in the large area substrate by Cu grid lines. Finally, a 50-cm2 scaled Cu2O photocathode with Cu grid lines was tested in an outdoor condition under natural sun. This is the first outdoor PEC demonstration of large-scale Cu2O photocathode with Cu grid lines, which gives insight into the development of efficient upscaled PEC photoelectrode.

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Impact Assessment of Phosphogypsum Leachate on Groundwater of Sfax-Agareb (Southeast of Tunisia): Using Geochemical and Isotopic Investigation

Journal of Chemistry ◽

10.1155/2018/2721752 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Samira Melki ◽

Moncef Gueddari

Keyword(s):

Physicochemical Parameters ◽

Large Scale ◽

Major Effect ◽

Major Elements ◽

Spatiotemporal Variation ◽

Water Residence Time ◽

Evaporation Process ◽

Natural Conditions ◽

Wide Range

The production of phosphoric acid by the Tunisian Chemical Group, in Sfax, Tunisia, led to the degradation of the groundwater quality of the Sfax-Agareb aquifer mainly by the phosphogypsum leachates infiltration. Spatiotemporal monitoring of the quality of groundwater was carried out by performing bimonthly sampling between October 2013 and October 2014. Samples culled in the current study were subject to physicochemical parameters measurements and analysis of the major elements, orthophosphates, fluorine, trace metals, and stable isotopes (18O, 2H). The obtained results show that the phosphogypsum leachates infiltration has a major effect on the downstream part of the aquifer, where the highest values of conductivity, SO42-, Ortho-P, and F-, and the lowest pH were recorded. In addition, these results indicated that phosphogypsum leachates contained much higher amount of Cr, Cd, Zn, Cu, Fe, and Al compared to the groundwater. Spatiotemporal variation of the conductivity and concentrations of major elements is linked to the phosphogypsum leachates infiltration as well as to a wide range of factors such as the natural conditions of feeding and the water residence time. Contents of O18 and 2H showed that the water of the Sfax-Agareb aquifer undergoes a large scale evaporation process originated from recent rainfall.

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FCAW vertical welding of “V” butt plate in AC UHV transmission line construction

MATEC Web of Conferences ◽

10.1051/matecconf/201817503001 ◽

2018 ◽

Vol 175 ◽

pp. 03001

Author(s):

Han Yang ◽

Chen Kerui ◽

Li Yang ◽

Qu Bao

Keyword(s):

Transmission Line ◽

Large Scale ◽

Optimal Allocation ◽

Welding Process ◽

Steel Structure ◽

Solid Core ◽

Flux Cored Arc Welding ◽

Welded Structure ◽

Wide Range

In twenty-first Century, China vigorously promoted the research and construction of AC and DC transmission technology in order to ensure the optimal allocation of energy resources in a large scale[1]. In the construction of AC UHV transmission line, the welding quality of tower and stiffening plate as the load bearing tower and the tension of the welded structure plays an important role in the overall quality of the steel structure. In the past, the welding process of semi automatic carbon dioxide solid core welding wire often has the characteristics of weld spatter not easy to clean up and low efficiency of welding. The semi-automatic CO2 flux cored arc welding, has the characteristics of current and voltage to adapt to a wide range, melting speed, has important significance for improving the process, this paper describes the technology in practical engineering applications, and developed the basic strategy of training for grid steel structure welding technicians. This paper also lists both V groove plate butt FCAW welding typical welding project, hope this welding process will continue to spread.

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Aggregated criterion for estimating the efficiency of functioning of sections of the Ulan-Bator railway

Южно-Сибирский научный вестник ◽

10.25699/sssb.2021.39.5.013 ◽

2021 ◽

pp. 159-164

Author(s):

С.И. Носков ◽

М.П. Базилевский ◽

Ю.А. Трофимов ◽

А. Буяннэмэх

Keyword(s):

Large Scale ◽

Idle Time ◽

State University ◽

Efficiency Function ◽

Personnel Decisions ◽

Similar Work ◽

Wide Range ◽

Communication Lines ◽

Computational Technology

В статье рассматривается проблема разработки (формирования) функции эффективности (агрегированного критерия, свертки критериев) входящих в состав Улан-Баторской железной дороги (УБЖД) участков, которая содержала бы специальным образом взвешенные частные характеристики качества функционирования этих участков. Решение этой проблемы осуществляется на основе разработанной в Иркутском государственном университете путей сообщения информационно-вычислительной технологии (ИВТ) многокритериального оценивания эффективности функционирования сложных социально-экономических и технических систем. ИВТ позволяет на модельном уровне оценивать эту эффективность одним числом (выраженным, например, в процентах), что открывает широкие возможности в управлении этими системами, поскольку позволяет выполнять, в частности, масштабный многофакторный сравнительный анализ деятельности однородных организационных и других структур и принимать на этой основе решения самого различного характера. Построена функция эффективности функционирования участков УБЖД, включающая в свой состав взвешенные частные индикаторы такой эффективности: погрузка, статическая нагрузка, выгрузка, отправление вагонов, перевозка пассажиров, простои вагонов с одной переработкой, простои местных вагонов, простои транзитных вагонов с переработкой, простои транзитных вагонов без переработки. На основе этой функции рассчитана масштабированная на сто процентов эффективность каждого участка. При этом все показатели предпочтения упорядочены по убыванию значимости. Подобная информация, формируемая с годичной периодичностью, может быть весьма полезна руководству УБЖД для принятия широкого спектра управленческих, в том числе кадровых, решений. Аналогичная работа может быть выполнена в интересах РАО РЖД. The article discusses the problem of developing (forming) an efficiency function (aggregated criterion, convolution of criteria) of the sections included in the Ulan Bator Railway (UBZhD), which would contain specially weighted private characteristics of the quality of the functioning of these sections. The solution to this problem is carried out on the basis of the information and computational technology (ICT) developed at the Irkutsk State University of communication lines for multi-criteria assessment of the effectiveness of the functioning of complex socio-economic and technical systems. IWT makes it possible at the model level to evaluate this efficiency by one number (expressed, for example, as a percentage), which opens up ample opportunities in the management of these systems, since it allows performing, in particular, a large-scale multifactorial comparative analysis of the activities of homogeneous organizational and other structures and on this basis solutions of the most varied nature. The function of the effectiveness of the functioning of the UBZhD sections has been built, which includes weighted private indicators of such efficiency: loading, static load, unloading, dispatch of cars, transportation of passengers, idle time of cars with one processing, idle time of local cars, idle time of transit cars with processing, idle time of transit cars without processing. Based on this function, a 100% scaled efficiency is calculated for each site. Moreover, all preference indicators are sorted in descending order of importance. Such information, generated on a yearly basis, can be very useful to the UBZhD leadership for making a wide range of managerial, including personnel, decisions. Similar work can be performed in the interests of RAO Russian Railways.

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CheckM: assessing the quality of microbial genomes recovered from isolates, single cells, and metagenomes

10.7287/peerj.preprints.554v2 ◽

2015 ◽

Cited By ~ 5

Author(s):

Donovan H Parks ◽

Michael Imelfort ◽

Connor T Skennerton ◽

Philip Hugenholtz ◽

Gene W Tyson

Keyword(s):

Large Scale ◽

Single Cells ◽

Metagenomic Data ◽

Marker Genes ◽

Specific Gene ◽

Diverse Range ◽

Automated Method ◽

A Genome ◽

Wide Range

Large-scale recovery of genomes from isolates, single cells, and metagenomic data has been made possible by advances in computational methods and substantial reductions in sequencing costs. While this increasing breadth of draft genomes is providing key information regarding the evolutionary and functional diversity of microbial life, it has become impractical to finish all available reference genomes. Making robust biological inferences from draft genomes requires accurate estimates of their completeness and contamination. Current methods for assessing genome quality are ad hoc and generally make use of a limited number of ‘marker’ genes conserved across all bacterial or archaeal genomes. Here we introduce CheckM, an automated method for assessing the quality of a genome using a broader set of marker genes specific to the position of a genome within a reference genome tree and information about the collocation of these genes. We demonstrate the effectiveness of CheckM using synthetic data and a wide range of isolate, single cell and metagenome derived genomes. CheckM is shown to provide accurate estimates of genome completeness and contamination, and to outperform existing approaches. Using CheckM, we identify a diverse range of errors currently impacting publicly available isolate genomes and demonstrate that genomes obtained from single cells and metagenomic data vary substantially in quality. In order to facilitate the use of draft genomes, we propose an objective measure of genome quality that can be used to select genomes suitable for specific gene- and genome-centric analyses of microbial communities.

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Large-area integration of two-dimensional materials and their heterostructures by wafer bonding

Nature Communications ◽

10.1038/s41467-021-21136-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Arne Quellmalz ◽

Xiaojing Wang ◽

Simon Sawallich ◽

Burkay Uzlu ◽

Martin Otto ◽

...

Keyword(s):

Wafer Bonding ◽

Semiconductor Manufacturing ◽

Large Scale ◽

Hexagonal Boron Nitride ◽

2D Materials ◽

High Volume ◽

Two Dimensional ◽

Wafer Level ◽

Large Area ◽

Wide Range

AbstractIntegrating two-dimensional (2D) materials into semiconductor manufacturing lines is essential to exploit their material properties in a wide range of application areas. However, current approaches are not compatible with high-volume manufacturing on wafer level. Here, we report a generic methodology for large-area integration of 2D materials by adhesive wafer bonding. Our approach avoids manual handling and uses equipment, processes, and materials that are readily available in large-scale semiconductor manufacturing lines. We demonstrate the transfer of CVD graphene from copper foils (100-mm diameter) and molybdenum disulfide (MoS2) from SiO2/Si chips (centimeter-sized) to silicon wafers (100-mm diameter). Furthermore, we stack graphene with CVD hexagonal boron nitride and MoS2 layers to heterostructures, and fabricate encapsulated field-effect graphene devices, with high carrier mobilities of up to $$4520\;{\mathrm{cm}}^2{\mathrm{V}}^{ - 1}{\mathrm{s}}^{ - 1}$$ 4520 cm 2 V − 1 s − 1 . Thus, our approach is suited for backend of the line integration of 2D materials on top of integrated circuits, with potential to accelerate progress in electronics, photonics, and sensing.

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Giant power factors in p- and n-type large-area graphene films on a flexible plastic substrate

npj 2D Materials and Applications ◽

10.1038/s41699-019-0128-0 ◽

2019 ◽

Vol 3 (1) ◽

Cited By ~ 11

Author(s):

Kaito Kanahashi ◽

Masatou Ishihara ◽

Masataka Hasegawa ◽

Hiromichi Ohta ◽

Taishi Takenobu

Keyword(s):

Vapor Deposition ◽

Large Scale ◽

Chemical Vapor ◽

Plastic Substrate ◽

Large Area ◽

Flexible Materials ◽

Graphene Films ◽

Wide Range ◽

Carrier Doping ◽

Electron Carriers

Abstract This study reports on the thermoelectric properties of large-area graphene films grown by chemical vapor deposition (CVD) methods. Using the electric double layer gating technique, both the continuous doping of hole or electron carriers and modulation of the Fermi energy are achieved, leading to wide-range control of the Seebeck coefficient and electrical conductivity. Consequently, the maximum power factors of the CVD-grown large-area graphene films are 6.93 and 3.29 mW m–1 K–2 for p- and n-type carrier doping, respectively. These results are the best values among large-scale flexible materials, such as organic conducting polymers and carbon nanotubes, suggesting that CVD-grown large-area graphene films have potential for thermoelectric applications.

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Synchrotron X-ray Topography Studies of Epitaxial Lateral Overgrowth of GaN on Sapphire

MRS Proceedings ◽

10.1557/proc-572-327 ◽

1999 ◽

Vol 572 ◽

Author(s):

Patrick J. Mcnally ◽

T. Tuomi ◽

R. Rantamaki ◽

K. Jacobs ◽

L. Considine ◽

...

Keyword(s):

Quantum Well ◽

Sapphire Substrate ◽

Large Scale ◽

Epitaxial Lateral Overgrowth ◽

Large Area ◽

X Ray ◽

Lateral Overgrowth ◽

Transmission Modes ◽

Multi Quantum Well

ABSTRACTSynchrotron white beam x-ray topography techniques, in section and large-area transmission modes, have been applied to the evaluation of ELOG GaN on A12O3. Using the openings in 100 nm thick SiO2 windows, a new GaN growth took place, which resulted in typical overgrowth thicknesses of 6.8 μm. Measurements on the recorded Laue patterns indicate that the misorientation of GaN with respect to the sapphire substrate (excluding a 30° rotation between them) varies considerably along various crystalline directions, reaching a maximum of a ∼0.66° rotation of the (0001) plane about the [01•1] axis. This is ∼3% smaller than the misorientation measured in the non-ELOG reference, which reached a maximum of 0.68°. This misorientation varies measurably as the stripe or window dimensions are changed. The quality of the ELOG epilayers is improved when compared to the non- ELOG samples, though some local deviations from lattice coherence were observed. Long range and large-scale (order of 100 μm long) strain structures were observed in all multi quantum well epilayers.

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Investigating the nature and quality of locally commissioned evaluations of the NHS Vanguard programme: an evidence synthesis

Health Research Policy and Systems ◽

10.1186/s12961-021-00711-3 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Paul Wilson ◽

Jenny Billings ◽

Julie MacInnes ◽

Rasa Mikelyte ◽

Elizabeth Welch ◽

...

Keyword(s):

Service Delivery ◽

Large Scale ◽

Evidence Synthesis ◽

Policy Makers ◽

Delivery Of Care ◽

Wide Range ◽

Registration Number ◽

Resource Data

Abstract Background With innovation in service delivery increasingly viewed as crucial to the long-term sustainability of health systems, NHS England launched an ambitious new model of care (Vanguard) programme in 2015. Supported by a £350 million transformation fund, 50 Vanguard sites were to act as pilots for innovation in service delivery, to move quickly to change the way that services were delivered, breaking down barriers between sectors and improving the coordination and delivery of care. Methods As part of a national evaluation of the Vanguard programme, we conducted an evidence synthesis to assess the nature and quality of locally commissioned evaluations. With access to a secure, online hub used by the Vanguard and other integrated care initiatives, two researchers retrieved any documents from a locally commissioned evaluation for inclusion. All identified documents were downloaded and logged, and details of the evaluators, questions, methodological approaches and limitations in design and/or reporting were extracted. As included evaluations varied in nature and type, a narrative synthesis was undertaken. Results We identified a total of 115 separate reports relating to the locally commissioned evaluations. Five prominent issues relating to evaluation conduct were identified across included reports: use of logic models, number and type of evaluation questions posed, data sharing and information governance, methodological challenges and evaluation reporting in general. A combination of resource, data and time constraints means that evaluations often attempted to but did not fully address the wide range of questions posed by individual Vanguards. Conclusions Significant investment was made in independent local evaluations of the Vanguard programme by NHS England. This synthesis represents the only comprehensive attempt to capture methodological learning and may serve as a key resource for researchers and policy-makers seeking to understand investigating large-scale system change, both within the NHS and internationally. PROSPERO (Registration number: CRD42017069282).

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