Showing posts with label Nature. Show all posts
Still 0 and 1? Check this out: Memory leads the way to better computing
Correspondence: H.-S. Philip Wong & Sayeef Salahuddin
H.-S. Philip Wong - Department of Electrical Engineering and the Stanford SystemX Alliance, Stanford University, Stanford, California 94305, USA
Sayeef Salahuddin - Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, USA
Nature Nanotechnology 10, 191–194 (2015) doi:10.1038/nnano.2015.29
More about Authors:
http://web.stanford.edu/~hspwong/
https://www.eecs.berkeley.edu/Faculty/Homepages/salahuddin.html
Introduction
Current memory devices store information in the charge state of a capacitor; the presence or absence of charges represents logic 1's or 0's. Several technologies are emerging to build memory devices in which other mechanisms are used for information storage. They may allow the monolithic integration of memories and computation units in three-dimensional chips for future computing systems1. Among those promising candidates are spin-transfer-torque magnetic random access memory (STT-MRAM) devices, which store information in the magnetization of a nanoscale magnet. Other candidates that are approaching commercialization include phase change memory (PCM), metal oxide resistive random access memory (RRAM) and conductive bridge random access memory (CBRAM).
Today's computing systems use a hierarchy of volatile and non-volatile data storage devices to achieve an optimal trade-off between cost and performance2. The portion of the memory that is the closest to the processor core is accessed frequently, and therefore it requires the fastest operation speed possible; it is also the most expensive memory because of the large chip area required. Other levels in the memory hierarchy are optimized for storage capacity and speed (Fig. 1). The main memory is often located in a separate chip because it is fabricated with a different technology from that of the microprocessor.
For over 30 years, static random access memory (SRAM)3 and dynamic random access memory (DRAM)3 have been the workhorses of this memory hierarchy4. Both SRAM and DRAM are volatile memories — that is, they lose the stored information once the power is cut off. For non-volatile data storage, magnetic hard disk drives (HDDs) have been in use for over five decades5, 6, 7. Since the advent of portable electronic devices such as music players and mobile phones, however, solid-state non-volatile memory known as Flash memory8 has been introduced into the information storage hierarchy between the DRAM and the HDD. Flash has become the dominant data storage device for mobile electronics; increasingly, even enterprise-scale computing systems and cloud data storage systems are using Flash to complement the storage capabilities of HDD.
For complete FREE article for:
- Electrical manipulation of magnetism in ferromagnets
- Electrical control of magnetization in multiferroics
image source: Controlling size and helicity of a spin-vortex skyrmion
Gold Nano Particles
Tiny treasure: The future of nano-gold @ Youtube
Below is a collection of Nature articles (seem free to access):
The promoting effect of adsorbed carbon monoxide on the oxidation of alcohols on a gold catalyst
Paramaconi Rodriguez, Youngkook Kwon & Marc T. M. Koper
Nature Chemistry 4, 177–182 (11 December 2011)
Nanoparticles that communicate in vivo to amplify tumour targeting
Geoffrey von Maltzahn, Ji-Ho Park, Kevin Y. Lin, Neetu Singh, Christian Schwöppe + et al.
Nature Materials 10, 545–552 (19 June 2011)
Optical detection of single non-absorbing molecules using the surface plasmon resonance of a gold nanorod
Peter Zijlstra, Pedro M. R. Paulo & Michel Orrit
Nature Nanotechnology 7, 379–382 (15 April 2012)
A high-throughput drug screen for Entamoeba histolytica identifies a new lead and target
Anjan Debnath, Derek Parsonage, Rosa M Andrade, Chen He, Eduardo R Cobo + et al.
Nature Medicine 18, 956–960 (20 May 2012)
An invisible metal–semiconductor photodetector
Pengyu Fan, Uday K. Chettiar, Linyou Cao, Farzaneh Afshinmanesh, Nader Engheta + et al. Nature Photonics 6, 380–385 (20 May 2012)
image source: Gold nanoparticles help detect Listeria cheaply
High Performance Bio-integrated Devices for Clinical Applications
Corresponding Author: Dae-Hyeong KIM dkim98@snu.ac.kr
Nature Communications 5, Article number: 5747 doi:10.1038/ncomms6747
Abstract:
Sensory receptors in human skin transmit a wealth of tactile and thermal signals from external environments to the brain. Despite advances in our understanding of mechano- and thermosensation, replication of these unique sensory characteristics in artificial skin and prosthetics remains challenging. Recent efforts to develop smart prosthetics, which exploit rigid and/or semi-flexible pressure, strain and temperature sensors, provide promising routes for sensor-laden bionic systems, but with limited stretchability, detection range and spatio-temporal resolution. Here we demonstrate smart prosthetic skin instrumented with ultrathin, single crystalline silicon nanoribbon strain, pressure and temperature sensor arrays as well as associated humidity sensors, electroresistive heaters and stretchable multi-electrode arrays for nerve stimulation. This collection of stretchable sensors and actuators facilitate highly localized mechanical and thermal skin-like perception in response to external stimuli, thus providing unique opportunities for emerging classes of prostheses and peripheral nervous system interface technologies.
The electronic version of this article is the complete one and can be found online at: http://www.nature.com/ncomms/2014/141209/ncomms6747/full/ncomms6747.html#access
image source: Scientists develop artificial skin that can feel rain and the touch of a hand