اختصاصی از نیک فایل Effects of Zr on the precursor architecture and high-temperature nanostructure evolution of SiOC polymer-derived ceramics دانلود با لینک مستقیم و پر سرعت .

Effects of Zr on the precursor architecture and high-temperature nanostructure evolution of SiOC polymer-derived ceramics

 

ژورنال: Journal of the European Ceramic Society

سال: October 2015

قیمت اصلی: 35.95$

Abstract

SiOC and SiZrOC ceramics were obtained starting from the hydrosilane system without and with zirconium n-propoxide (Zr(OⁿPr)₄) by sol–gel route. The precursor architectures indicated that the presence of SiH bonds leads to a different cross-linking mechanism of SiZrOC precursor, where the SiH bonds were involved in the formation of SiOZr bonds. The presence of Zr caused a lower content of sp³ carbon in SiZrOC ceramics. At above 1400 °C, the sp3-C/Si ratio in both ceramics increased due to carbothermal reduction, especially rapidly for SiOC ceramics, suggesting the carbothermal reduction in SiZrOC ceramics has been strongly suppressed with the presence of ZrO₂. Raman spectroscopy showed the graphitization degree of free carbon increased with temperature in both ceramics, but was always lower in SiZrOC ceramics. The SiZrOC ceramics has been found to exhibit remarkably high temperature stability with respect to carbothermal decomposition up to 1600 °C in comparison with the SiOC ceramics.

Keywords

• SiZrOC polymer-derived ceramics; 
• Precursor architecture; 
• Nanostructure evolution;
• Free carbon

اختصاصی از نیک فایل Seismic architecture, stratigraphy and evolution of a subtropical marine embayment: Maputo Bay, Mozambique دانلود با لینک مستقیم و پر سرعت .

Seismic architecture, stratigraphy and evolution of a subtropical marine embayment: Maputo Bay, Mozambique

ژورنال:Marine Geology

سال:November 2015

قیمت اصلی:37.95$

Abstract

The seismic stratigraphy, architecture and evolution of a large subtropical embayment, Maputo Bay, Southern Mozambique is described. Nine seismic units are documented; and show repeated phases of incised valley formation and transgressive infilling. Trangressive infilling alternates between the classic wave-dominated transgressive succession of fluvial and central estuarine bay deposits and the filling by intertidal flat and tidal bedforms developed during stages of inlet restriction and shallowing associated with barrier growth at stillstand intervals. Imprinted on the succession are several key facets of subtropical stratigraphy, hurricane-generated erosional surfaces and beachrock horizons. The upper stratigraphy comprises the highstand bayhead delta, a prograding feature constructed by several flood events. In comparison with literature from other similar systems such as lagoons, coastal lakes and estuaries, a generic three stage stratigraphic model of large marine embayments is proposed that includes incisionduring glaciations; transgressive infilling during deglaciations; and shallowing during thestillstand episodes of the recent deglaciation.

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Keywords

• Marine embayments, Seismic architecture, Incised valleys, Transgressive infilling,
• Mozambique

Chapter 6 – Neurocognitive Architectures and the Nonsymbolic Foundations of Fractions Understanding

اختصاصی از نیک فایل Chapter 6 – Neurocognitive Architectures and the Nonsymbolic Foundations of Fractions Understanding دانلود با لینک مستقیم و پر سرعت .

Chapter 6 – Neurocognitive Architectures and the Nonsymbolic Foundations of Fractions Underst

ژورنال:Development of Mathematical Cognition

سال:2016

قیمت اصلی:31.50$

Abstract

Children and adults experience pervasive difficulties understanding symbolic fractions. These difficulties have led some to propose that components of the human neurocognitive architecture, especially systems like the approximate number system (ANS), are ill-suited for learning fraction concepts. However, recent research in developmental psychology and neuroscience has revealed neurocognitive architectures—a “ratio processing system” (RPS)—tuned to the holistic magnitudes of nonsymbolic ratios that may be ideally suited for grounding fraction learning. We review this evidence alongside our own recent behavioral and brain imaging work demonstrating that nonsymbolic ratio perception is related to understanding fractions. We argue that this nonsymbolic RPS supports symbolic fraction understanding, similar to how the ANS supports whole-number understanding. We then outline a number of open questions about the RPS and the ways in which it may be used to support fractions learning.

Keywords

• Fractions, Neurocognitive architecture, Educational neuroscience, Fractions instruction,Nonsymbolic ratios, Ratio processing system, Perceptually based training

اختصاصی از نیک فایل A novel consumer-centric card management architecture and potential security issues دانلود با لینک مستقیم و پر سرعت .

A novel consumer-centric card management architecture and potential security issues

ژورنال:Information Sciences

سال:November 2015

قیمت اصلی:37.95$

Abstract

Multi-application smart card technology has gained momentum due to the Near Field Communication (NFC) and smart phone revolution. Enabling multiple applications from different application providers on a single smart card is not a new concept. Multi-application smart cards have been around since the late 1990s; however, uptake was severely limited. NFC has recently reinvigorated the multi-application initiative and this time around a number of innovative deployment models are proposed. Such models include Trusted Service Manager (TSM), User Centric Smart Card Ownership Model (UCOM) and GlobalPlatform Consumer-Centric Model (GP-CCM). In this paper, we discuss two of the most widely accepted and deployed smart card management architectures in the smart card industry: GlobalPlatform and Multos. We explain how these architectures do not fully comply with the UCOM and GP-CCM. We then describe our novel flexible consumer-centric card management architecture designed specifically for the UCOM and GP-CCM frameworks, along with ways of integrating the TSM model into the proposed card management architecture. Finally, we discuss four new security issues inherent to any architecture in this context along with the countermeasures for our proposed architecture.

Keywords

• Smart card, GlobalPlatform, Java Card, Multos, User centric smart cards,
• Card management architecture

Family and Friends 5 Unit 5 to 8 Exam

اختصاصی از نیک فایل Family and Friends 5 Unit 5 to 8 Exam دانلود با لینک مستقیم و پر سرعت .

Family and Friends 5 Unit 5 to 8 Exam

آزمون فمیلی فرندز 5 طراحی شده توسط گروه آموزشی اَوَس طبق نسخه امریکن می باشد.در آن سعی شده است مهارتهای مختلف زبانی و محتویات درسی را تحت پوشش قرار دهد.

بسته آزمون دربرگیرنده دو فایل سوال با فرمت قابل ویرایش word و PDF بهمراه فایل صوتی می باشد.