Harvesting Lost Photons: Plasmon and Upconversion Enhanced Broadband Photocatalytic Activity in Core@Shell Microspheres Based on Lanthanide‐Doped NaYF4, TiO2, and Au

Efficiently harvesting solar energy for photocatalysis remains very challenging. Rational design of architectures by combining nanocomponents of radically different properties, for example, plasmonic, upconversion, and photocatalytic properties, offers a promising route to improve solar energy utilization. Herein, the synthesis of novel, plasmonic Au nanoparticle decorated NaYF₄:Yb³⁺, Er³⁺, Tm³⁺‐core@porous‐TiO₂‐shell microspheres is reported. They exhibit high surface area, good stability, broadband absorption from ultraviolet to near infrared, and excellent photocatalytic activity, significantly better than the benchmark P25 TiO₂. The enhanced activity is attributed to synergistic effects from nanocomponents arranged into the nanostructured architecture in such a way that favors the efficient charge/energy transfer among nanocomponents and largely reduced charge recombination. Optical and energy‐transfer properties are modeled theoretically to support our interpretations of catalytic mechanisms. In addition to yielding novel materials and interesting properties, the current work provides physical insights that can contribute to the future development of plasmon‐enhanced broadband catalysts.     

Semiconductor Yield Analysis and Multi-Chip Package(MCP) Dic Pairing Optimization using Machine Learning

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Increasing inequalities in what we do online: A longitudinal cross sectional analysis of Internet activities among the Dutch population (2010 to 2013) over gender,age, education,and income

We investigate types of Internet activities among a representative sample of the Dutch population from 2010 to 2013. We examined usage patterns of seven types of Internet activities (i.e., information, news, personal development, commercial transaction, social interaction, leisure, and gaming) and related these patterns with gender, age, education, and income. Activities related to news, personal development, commercial transaction, and social interaction increased in popularity. For most capital enhancing activities, men, younger people, higher educated people, and people with higher than average incomes were prominent. These observations, however, are subject to change. The Internet seems to provide increasingly more capital-enhancing opportunities for those with higher education and income, which would accordingly reinforce their already strong positions in society.     

Asymptotic Stability Conditions and Estimates of Solutions for Nonlinear Multiconnected Time-Delay Systems

This paper examines certain classes of multiconnected (complex) systems with time-varying delay. Delay-independent stability conditions and estimates of the convergence rate of solutions to the origin for those systems are derived. It is shown that the exponents in the obtained estimates depend on the parameters of Lyapunov functions constructed for the corresponding isolated subsystems. The problem of computing parameter values that provide the most precise estimates is investigated. Some examples are presented to demonstrate the effectiveness of the proposed approaches.     

A preamble-based approach for providing quality of service support in wireless sensor networks

Medium Access Control (MAC) protocols for Wireless Sensor Networks (WSN) are usually designed as random access protocols that apply different kinds of backoff strategies since Time Division Multiple Access (TDMA) based protocols with admission control are very complex and require additional mechanisms for synchronization. Without such mechanisms, fair or priority based medium access with Quality of Service (QoS) guarantees can hardly be achieved by existing protocols. Therefore, we developed a random access protocol which uses a new preamble-based medium access strategy that enables collision-free priority based access without the need of synchronization. In this paper we introduce different QoS strategies and their use cases. All strategies can be easily integrated in our protocol to meet the requirements of different target applications. Furthermore, we compare the performance of the strategies with a typical carrier-sense based protocol.     

Survey on location information services for Vehicular Communication Networks

Vehicular Communication Networks (VCNs) are used to supply a communication platform for Intelligent Transportation Systems services also for value added services in different road systems. In comparison to other communication networks, VCNs come with major challenges: high mobility and velocity of vehicles that cause rapidly change topology of network and fast change of vehicle’s locations. Location information services (LISs) or location management systems (LMSs) are used to provide location information about vehicles such as current location, speed, direction and report this information to other vehicles or network entities that require this information. We present a survey for LISs in VCNs and introduce 11 approaches in literature. Moreover, we present a classification for LISs and compare mentioned approaches based on our classification. Finally we evaluate studied LISs by some performance properties to measure their overall efficiency.     

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Here, a new, fast, and versatile method for the incorporation of colloidal quantum dots (QDs) into ionic matrices enabled by liquid–liquid diffusion is demonstrated. QDs bear a huge potential for numerous applications thanks to their unique chemical and physical properties. However, stability and processability are essential for their successful use in these applications. Incorporating QDs into a tight and chemically robust ionic matrix is one possible approach to increase both their stability and processability. With the proposed liquid–liquid diffusion‐assisted crystallization (LLDC), substantially accelerated ionic crystallization of the QDs is shown, reducing the crystallization time needed by one order of magnitude. This fast process allows to incorporate even the less stable colloids including initially oil‐based ligand‐exchanged QDs into salt matrices. Furthermore, in a modified two‐step approach, the seed‐mediated LLDC provides the ability to incorporate oil‐based QDs directly into ionic matrices without a prior phase transfer. Finally, making use of their processability, a proof‐of‐concept white light emitting diode with LLDC‐based mixed QD‐salt films as an excellent color‐conversion layer is demonstrated. These findings suggest that the LLDC offers a robust, adaptable, and rapid technique for obtaining high quality QD‐salts.