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An electron source with an array of individually controllable single tips allows the observation of each emitter current simultaneously as well as the measurement of the integral current. Furthermore, the initial activation process of the individual tips and current distribution of the source can be examined. The Si cathode consists of an array of 2 x 2 conically shaped emitter structures on a borosilicate glass substrate. The emitters were fabricated by laser micromachining and wet etching. Integral field emission (FE) measurements were performed in a diode configuration in a vacuum chamber at pressures of about 10(-9) mbar with a self-aligned Si extraction grid, due to adjustment pins. The total emission current was regulated to a predefined value (4.0, 10, 20, 40, and 50 mu A) by an external regulating circuit and recorded individually during the measurement. The onset voltage for a current of 1 nA varied between 320 and 430 V. The voltage conversion factor is in the range of 7.6 x 10(4) cm(-1) to 1.3 x 10(5) cm(-1). Constant currentmeasurementsover a longer periodof time (1800 values with a sample rate of 0.5 Hz) were performed and show a total current fluctuation less than 0.6% due to the regulation circuit. Despite the stable total current in regulated operation, it was observed that the individual emitters fluctuate up to 75% for low (similar to 10(-8) A) and 5% for high (similar to 10(-5) A) currents.
Arrays of 4x4 conical shaped emitters were directly structured by laser micromaching. Assembled as an electron source with a spacer and Si-grid, they were investigated by means of IV-measurement in ultra-high vacuum. The IV-measurements of the sample show integral emission currents up to 10 µA at a voltage of 1000 V (11 MV/m). Initially, an ideal FN-behaviour is noticeable. The deviation for higher voltage values in the FN-plot is caused by the change of the work function, which was proven by numerical calculations.
This paper presents a simple and systematic approach to determine the equivalent frequency-independent circuit model for a dual-band planar antenna. The Foster Canonical network synthesis technique with two RLC tanks has been employed to generate the two resonant bands of the antenna. The transfer function model is subsequently refined using a data fitting algorithm (viz the Nelder-Mead simplex algorithm). Parametric adjustments are performed at the final stage in order to further improve the accuracy of the final parameters.
The current analyses present results of running ductile fracture propagation in high strength X100 line pipe steels under the influence of anisotropy. Mechanical anisotropy is commonly available in pipe products as a result of the manufacturing process, especially, those subjected to hot/cold-worked deformation. The outcomes of the present analyses show that its effect on the behavior of running ductile fracture in cracked pipes undergoing depressurization is meaningful. For instance, the Crack-Tip Opening Angle (CTOA) not only exhibits a strong dependence to the pipe's diameter size, but also to the material's anisotropy nature when compared to a hypothetical isotropic material. Moreover, laboratory scale tests such as those performed on Battelle Drop Weight Tear (BDWT) samples provide useful information about initiation of ductile crack propagation when the anisotropy features are taken into account in the material description.
The increasing popularity of nanoparticles in many applications has led to the fact that these persistent materials pollute our environment and threaten our health. An online sensor system for monitoring the presence of nanoparticles in fresh water would be highly desired. We propose a label-free sensor based on SPR imaging. The sensitivity was enhanced by a factor of about 100 by improving the detector by using a high-resolution camera. This revealed that the light source also needed to be improved by using LED excitation instead of a laser light source. As a receptor, different self-assembled monolayers have been screened. It can be seen that the nanoparticle receptor interaction is of a complex nature. The best system when taking sensitivity as well as reversibility into account is given by a dodecanethiol monolayer on the gold sensor surface. Lanthanide-doped nanoparticles, 29 nm in diameter and with a similar refractive index to the most common silica nanoparticles were detected in water down to 1.5 mu g mL(-1). The sensor can be fully regenerated within one hour without the need for any washing buffer. This sensing concept is expected to be easily adapted for the detection of nanoparticles of different size, shape, and composition, and upon miniaturization, suitable for long-term applications to monitor the quality of water.
Cloud Computing Adoption: A Literature Review on What Is New and What We Still Need to Address
(2021)
Research on cloud computing (CC) recently emerged congruently with the technology’s importance for organizations at a fast pace. This makes it difficult for practitioners to obtain a consolidated overview of what determines CC adoption based on the numerous papers in this regard. Moreover, for further research in the field to add value, it is necessary to identify what still needs to be addressed. In this vein, we conducted a descriptive review of 39 papers, integrating the results of a previous review on 23 papers from 2014, to compare findings across studies. We identify 44 determinant factors that exhibit consistent directional influence on the dependent meta-variable “CC adoption”, extending previous literature reviews with regard to asset, client, and environmental characteristics. We then critically reviewed the research landscape to identify what is there, and what is not yet covered: Future research should specifically regard the adoption of Infrastructure-, Platform-, and Everything-as-a-Service, private, hybrid, and multi-cloud deployment, investigate vendor, solution, and individual characteristics, analyzing information systems, or the decision-maker.
Most large-scale organizations adopted Cloud Computing (CC) on a company level in recent years. Managers now face the challenge to appropriately implement CC "operationally", i.e., for information systems (ISs). We refer to this as post-adoption, addressing the extent of technology usage after adoption. Specifically, managers need to choose among the CC delivery models Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-asa-Service (SaaS). We differentiate the determinants of this post-adoption decision for IaaS, PaaS, and SaaS. Based on this analysis, we derive criteria that guide managers' delivery model selection: Adopt 1) IaaS for ISs requiring flexibility and reduced time to market, 2) PaaS to access specialized resources, and 3) SaaS to focus on core competencies. Moreover, we analyze the impact on the CC strategy and postulate them as recommendations: I) acknowledge the interplay between governance and time-to-market, II) realize cost savings on company level, and III) consider strategically important ISs for CC.
For its third installment, the Data Science Challenge of the 19th symposium “Database Systems for Business, Technology and Web” (BTW) of the Gesellschaft für Informatik (GI) tackled the problem of predictive energy management in large production facilities. For the first time, this year’s challenge was organized as a cooperation between Technische Universität Dresden, GlobalFoundries, and ScaDS.AI Dresden/Leipzig. The Challenge’s participants were given real-world production and energy data from the semiconductor manufacturer GlobalFoundries and had to solve the problem of predicting the energy consumption for production equipment. The usage of real-world data gave the participants a hands-on experience of challenges in Big Data integration and analysis. After a leaderboard-based preselection round, the accepted participants presented their approach to an expert jury and audience in a hybrid format. In this article, we give an overview of the main points of the Data Science Challenge, like organization and problem description. Additionally, the winning team presents its solution.
Aim of the study was to develop a standardized model system to investigate endodontic irrigation techniques and assess the efficiency of different activation methods on the removal of hard tissue debris in complex root canal systems. Mesial roots of mandibular molars were firstly scanned by micro-computed tomography (µCT) and allocated to three groups of irrigant activation: sonic activation (EDDY, VDW, Munich, Germany), laser activation (AutoSWEEPS, FOTONA, Ljubljana, Slovenia) and conventional needle irrigation (control). Roots were fixed in individual 3D-printed holders to facilitate root canal enlargement under constant irrigation with NaOCl (5%). To enable standardized quantification of remaining debris, BaSO4-enriched dentine powder was compacted into the canals, followed by another µCT-scan. The final irrigation was performed using 17% ethylenediaminetetraacetic acid (EDTA) and 5% sodium hypochlorite (NaOCl) with the respective activation method, and the volume of remaining artificial debris was quantified after a final µCT-scan. The newly developed model system allowed for reliable, reproducible and standardized assessment of irrigation methods. Activation of the irrigant proved to be significantly more effective than conventional needle irrigation regarding the removal of debris, which persisted particularly in the apical third of the root canal in the control group. The efficiency of irrigation was significantly enhanced with laser- and sonic-based activation, especially in the apical third.