Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

A review of the electrochemical performance of alloy anodes for lithium-ion batteries

Research to develop alternative electrode materials with high energy densities in Li-ion batteries has been actively pursued to satisfy the power demands for electronic devices and hybrid electric vehicles. This critical review focuses on anode materials composed of Group IV and V elements with their composites including Ag and Mg metals as well as transition metal oxides which have been intensively investigated. This critical review is devoted mainly to their electrochemical performances and reaction mechanisms (313 references).

Li-alloy based anode materials for Li secondary batteries.

Autonomic communications seek to improve the ability of network and services to cope with unpredicted change, including changes in topology, load, task, the physical and logical characteristics of the networks that can be accessed, and so forth. Broad-ranging autonomic solutions require designers to account for a range of end-to-end issues affecting programming models, network and contextual modeling and reasoning, decentralised algorithms, trust acquisition and maintenance---issues whose solutions may draw on approaches and results from a surprisingly broad range of disciplines. We survey the current state of autonomic communications research and identify significant emerging trends and techniques.

A survey of autonomic communications

The tributylphenyltin (TBPT)-encapsulated resorcinol (R)−formaldehyde (F) sol was prepared inside the micelles of cetyltrimethylammonium bromide (CTAB). This core−shell-type sol was polymerized and further carbonized to obtain nanosized Sn-encapsulated spherical hollow carbon. The size of spherical hollow carbon and Sn metal particles was controllable by changing the R/CTAB or TBPT/CTAB mole ratio, respectively. It is likely that, when tested as the anode in Li secondary batteries, the spherical hollow carbon acts as a barrier to prevent the aggregation of nanosized Sn particles and provides a void space for Sn metal particles to experience a volume change without a collapse of carbon shell, giving rise to a better cycle performance than that of pure Sn metal.

Synthesis of tin-encapsulated spherical hollow carbon for anode material in lithium secondary batteries

We have built an ad hoc protocol evaluation testbed (APE) in order to perform large-scale, reproducible experiments. APE aims at assessing several different routing protocols in a real-world environment instead of by simulation. We present the APE testbed architecture and report on initial experiments with up to 37 physical nodes that show the reproducibility and scalability of our approach. Several scenario scripts have been written that include strict choreographic instructions to the testers who walk around with ORiNOCO equipped laptops. We introduce a mobility metric called virtual mobility that we use to compare different test runs. This metric is based on the measured signal quality instead of the geometric distance between nodes, hence it reflects how a routing protocol actually perceives the network's dynamics.

/pdf/a-large-scale-testbed-for-reproducible-ad-hoc-protocol-1xw51i1mhs.pdf

A large-scale testbed for reproducible ad hoc protocol evaluations

Internet services run on multiple servers in different locations, serving clients that are often mobile and multihomed. This does not match well with today's network stack, designed for communication between fixed hosts with topology-dependent addresses. As a result, online service providers resort to clumsy and management-intensive work-arounds--forfeiting the scalability of hierarchical addressing to support virtual server migration, directing all client traffic through dedicated load balancers, restarting connections when hosts move, and so on.

In this paper, we revisit the design of the network stack to meet the needs of online services. The centerpiece of our Serval architecture is a new Service Access Layer (SAL) that sits above an unmodified network layer, and enables applications to communicate directly on service names. The SAL provides a clean service-level control /data plane split, enabling policy, control, and in-stack name-based routing that connects clients to services via diverse discovery techniques. By tying active sockets to the control plane, applications trigger updates to service routing state upon invoking socket calls, ensuring up-to-date service resolution. With Serval, end-points can seamlessly change network addresses, migrate flows across interfaces, or establish additional flows for efficient and uninterrupted service access. Experiments with our high-performance in-kernel prototype, and several example applications, demonstrate the value of a unified networking solution for online services.

/pdf/serval-an-end-host-stack-for-service-centric-networking-198o7qve4x.pdf

Serval: an end-host stack for service-centric networking

After almost a decade of research into ad hoc networking, MANET technology has not yet affected our way of using wireless networks. In this paper we discuss lessons to draw and back them with experiences from our experimental work. We find that simulations have to be complemented to a much higher degree by real-world experiments, that there is a lack of mature implementations and integration and that efforts should be focused on more realistic settings inside the ''ad hoc horizon'' where decent network services still can be provided.

/pdf/lessons-from-experimental-manet-research-ym19wlzg8i.pdf

Lessons from experimental MANET research

Structural Transformations in Lithiated n´-Cu 6 Sn 5 Electrodes Probed by In Situ Mossbauer Spectroscopy and X-Ray Diffraction

Structural Transformations in Lithiated η′-Cu6Sn5 Electrodes Probed by In Situ Mössbauer Spectroscopy and X-Ray Diffraction

Our experiments with IEEE 802.11b based wireless ad hoc networks show that neighbor sensing with broadcast messages introduces "communication gray zones": in such zones data messages cannot be exchanged although the HELLO messages indicate neighbor reachability. This leads to a systematic mismatch between the route state and the real world connectivity, resulting in disruptive behavior. Concentrating on AODV we explore this issue and present three different techniques to overcome the gray zone problem.

https://www.it.uu.se/research/group/core/publications/LundMC2R2002.pdf

Erik Nordström

Papers

A large-scale testbed for reproducible ad hoc protocol evaluations

Serval: an end-host stack for service-centric networking

Lessons from experimental MANET research

Structural Transformations in Lithiated η′-Cu6Sn5 Electrodes Probed by In Situ Mössbauer Spectroscopy and X-Ray Diffraction

The gray zone problem in IEEE 802.11b based ad hoc networks