Structure and mechanical properties of unidirectionally solidified Fe-Cr-C and Fe-Cr-X-C alloys

In this work four different microstructures were obtained by unidirectional solidification of Fe-Cr-C eutectic alloys. Conditions for zone coupled growth were determined in alloys containing approximately 30 wt pct chromium. Furthermore, mechanical testing indicated that the maximum strength was exhibited by Fe-30Cr-C alloys with cerium or titanium additions. These alloys had the largest volume fraction of eutectic fibers and their ultimate tensile strength was of the order of 3250 MPa. Correlations between the rate of crystal growth(u) and fiber spacing (λ) or tensile strength(Rm) were found and an expression of the typeRm = Aλ^-b2 was obtained whereb ₂ varied between 0.283 and 0.685. Finally, manganese or chromium (35 wt pct Cr) additions did not lead to appreciable improvements in composite strength for this alloy system.     

Digital rights management in information publishing

In this article, we present a solution to digital rights management (DRM) for electronic publishing and document management services provided by a third-party application service provider (ASP). We identify legal requirements that service providers have to guarantee with respect to DRM. We elaborate on related technological requirements and implement specific DRM service components compliant with the Open Digital Rights Language (ODRL) standard. Moreover, we show how digital rights of document content can be specified and subsequently enforced using ODRL. We conclude by discussing legal implications of technological innovation—for example, the conflicts that may arise between digital rights enforcement and privacy protection measures, and how it is possible to resolve them.     

ASTM D33:核电设施防护涂层和内衬装置委员会

正ASTM D33核电设施防护涂层和内衬装置委员会在民用核电工业中发挥着重要作用。委员会制定了核电站用防护涂层的检测方法、规范和指南,旨在保护各部件免受腐蚀,从而确保在设计基准事故中防护涂层的有效性;还制定指南类标准,涉及核电站日常维护中如何管理涂层维护计划以及涂层应用和检验人员     

Identifying research topics in marketing science along the past decade: a content analysis

In recent years, how marketing science is conceptualized has changed, as have the methods through which data are investigated. This reconceptualization is making a significant impact on the most important topics of this discipline. Here, a novel approach is used to analyse a collection of 1169 abstracts from articles published in the Journal of Marketing Research and the Journal of Marketing from 2005 to 2014. We apply statistical methods to answer the following questions: How is vocabulary commonly used in marketing science? What are the most relevant topics of these journals? Which articles are the most influential? What words do authors prefer? Is the consumer among the primary topics in marketing research? A set of easy-to-read visual representations are provided to answer these questions. We highlight two main findings: (i) consumers and customers are the main topics of these marketing research journals, which emphasizes the growing interest in consumers and consumer behaviour as the core of both brick-and-mortar and online businesses; and (ii) in contrast to previous periods, product has become an essential concept, perhaps due to the emergence of new product considerations and new and enhanced interrelations.     

Voltage-controlled reverse filament growth boosts resistive switching memory

Nonvolatile memory devices based on filamentary resistance switching (RS) areamong the frontrunners to fuel future devices and sensors of the internet of things (IoT) era. The capability of many metal-insulator-metal cells to switch between two distinctive resistive states in response to an external electrical stimulus has been demonstrated. Through years of selection, cells based on the drift of metal ions, namely conductive-bridge memory devices, have shown a wide range of applications with nanosecond switching speeds, nanometer scalability, high-density, and low power-consumption. However, for low (sub-10-μA) current operation, a critical challenge is still represented by programming variability and by the stability of the conductive filament over time. Here, by introducing the concept of reverse filament growth (RFG), we managed to control the structural reconfiguration of the conductive filament inside a memory cell with significant enhancements of each of the aforementioned properties. A first-in-class Cu-based switching device is demonstrated, with a dedicated stack that enabled us to systematically trigger RFG, thus tuning the device’s properties. Along with nanosecond switching speeds, we achieved an endurance of up to 10⁶ cycles with a 10² read window, with outstanding disturb immunity and optimal stability of the filament over time. Furthermore, by tuning the filament’s shape, an excellent control of multi-level bit operations was achieved. Thus, this device offers high flexibility in memory applications.

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The Editorial Board

Editorial

The Editorial Board     

Transistor‐level optimization methodology for the complete design of switched‐capacitor filter circuits

This paper presents an automatic procedure for the design and optimization of switched‐capacitor (SC) filters, including the automatic sizing of transistors in the amplifiers and switches. The optimization procedure is based on genetic algorithms (GAs) where the circuit's fitness is first computed using equations describing the filter's transfer function and then using transient simulations. These equations are obtained using a fast numerical methodology that takes into consideration the electrical behavior of all components in the circuit. The poles and zeros of the SC filter's transfer function are computed using a system of differential equations, obtained from the inspection of the circuit. This system describes the filter's behavior for all switch combinations, including the non‐ideal effects of the transistors in the switches and amplifiers. Due to the low computational effort and accuracy of this methodology, it is possible to use a large population in the GA. After finding a solution through equations, the more computationally intensive SPICE transient simulations are used to fine‐tune the solution, with a much smaller population in the GA. Taking advantage of the equations' low computational load and accuracy, process, voltage, temperature (PVT) corners and mismatch errors optimizations are also performed, allowing the chromosomes fitness to be calculated taking into consideration multiple cases, thus resulting in a low sensitivity design.     

Determination of Lead in Spiked Seawater Samples by Electrothermal Atomic Absorption Spectrometry using Chemical Modifiers

Abstract

The determination of lead in spiked sodium chloride solution with 3.4% salinity and natural sea‐water samples by electrothermal atomic absorption spectrometry (ETAAS) with Zeeman‐effect background correction was investigated using neodymium, samarium, and erbium salts as modifiers with the addition of citric acid (CA) as a reducing agent. In order to demonstrate the high potential of rare earth metals in combination with citric acid, optimum pyrolysis temperature, atomization temperature, and optimum masses of neodymium, samarium, and erbium were found for the determination of lead. These modifiers were used for the determination of lead in sodium chloride solution with 3.4% salinity and in natural sea water samples by means of the calibration graphs prepared with pure analyte solutions.

The detection limits for lead spiked sample matrices were calculated with the 2σ criterion between 2.0 to 2.1 ng mL^?1 for neodymium and citric acid, between 5.3 to 7.4 ng mL^?1 for samarium and citric acid, and between 1.7 to 2.1 ng mL^?1 for erbium and citric acid and for a sample volume of 10 µL. The recoveries for lead spiked sea water samples were 97–102%, with neodymium and citric acid modifier and erbium and citric acid modifier. They were only 66–68% without modifier.