Low-complexity MIMO blind, adaptive channel shortening

Channel shortening is often employed as a means of mitigating intersymbol and intercarrier interference (ISI and ICI) in systems using multicarrier modulation. The Multicarrier Equalization by Restoration of RedundancY (MERRY) algorithm has previously been shown to blindly and adaptively shorten a channel to the length of the guard interval in a multicarrier system. This paper addresses synchronization and complexity reduction issues that were not dealt with in previous work and provides extensions to and generalizations of the MERRY algorithm. A modification is presented that removes the square root and division needed at each iteration without introducing additional complexity, with the added benefit of allowing the use of constraints other than a unit norm equalizer; an extension is proposed that allows for the use of more data in the MERRY update; the algorithm is generalized to the multiple-input multiple output (MIMO) and fractionally spaced cases; a low-complexity, blind symbol synchronization technique is proposed, and a method is proposed for blind initialization of the algorithm to avoid slow modes of convergence. Each extension to the basic MERRY algorithm is accompanied by an illustrative simulation example.     

A CMOS rectifier-integrator for amplitude detection in hard diskservo loops

In this paper a CMOS alternative amplitude detection system is presented. It is designed as an alternative for the, bipolar, amplitude detection in hard disk servo systems. The amplitude is detected by converting the input voltage to a current, rectifying the current, and integrating it on a capacitor. For this a new OTA topology and a rectifier cell are designed. This circuitry is expanded with a very linear current mirror and an automatic offset compensation system to cope with technology spread. The measured accuracy of the amplitude detector is 0.2% (9 b). This makes the circuit suitable for implementation in state-of-the art hard disk systems with very high track densities and very short access times. Because the circuit is realized in standard CMOS it is a further step toward CMOS only hard disk electronics. Because the circuit operates from a single 3 V power supply and has limited power consumption it can be used in battery powered systems     

A multimode 0.3-200-kb/s transceiver for the 433/868/915-MHz bands in 0.25-/spl mu/m CMOS

A fully integrated transceiver suitable for low-data-rate wireless telemetry and sensor networks operating in the license-free ISM frequency bands at 433, 868, or 915 MHz implemented in 0.25-/spl mu/m CMOS is presented. G/FSK, ASK, and OOK modulation formats are supported at data rates from 0.3 to 200 kb/s. The transceiver's analog building blocks include a low-noise amplifier, mixer, channel filter, received signal-strength indication, frequency synthesizer, voltage-controlled oscillator, and power amplifier. FSK demodulation is implemented using a novel digital complex-frequency correlator that operates over a wide modulation-index range and approximates matched filter detection performance. Automatic gain control, automatic frequency control, and symbol timing recovery loops are included on chip. Operating in the 915-MHz band in FSK mode at 9.6 kb/s, the receiver consumes 19.7 mA from a 3-V supply and achieves a sensitivity of -112.8dBm at 0.1% BER. The transmitter consumes 28.5 mA for an output power of 10 dBm and delivers up to 14 dBm.     

Investigation of physical and chemical property changes of ultra low-κ SiOCH in aspect of cleaning and chemical repair processes

The physical and chemical property changes of chemical vapor deposited ultra low-κ (ULK) SiOCH dielectric films due to different post ash treatments were studied by Auger electron spectroscopy, ellipsometric porosimetry and surface free energy evaluation. Structural changes in the ULK layer with respect to the carbon content were analyzed. Using a downstream and a reactive ion etch process for photo resist removal a reduction of carbon was observed. For different plasma gas chemistries the pore size reduction depends first on the process condition (downstream or reactive ion etch) and then on the gas. Differences in the pore size then also influence the amount of carbon depletion besides the influence of the gases used for photo resist processes. The damage at the surfaces was characterized by contact angle measurements providing both the polar and dispersive part of the surface free energy. The wettability of different solvents and repair chemicals was classified calculating their surface free energies and comparing those energies with the surface free energies of modified ULK surface. It is shown that especially reducing gases provide a surface free energy with a higher dispersive part compared to oxidative plasma treatments. Furthermore it was found that the wettability of repair chemicals and solvents strongly changes for reductive based strip processes with plasma exposure time, since a high variation of the surface free energy occur.     

超越“纳米级”设计时代

毫无疑问,我们正在跨入“纳米级”设计时代（处于1000nm到1nm级别的设计）的后期阶段。在未来18个月内,我们将开始部署32nm设计流程;而且,从32nm跨越到22nm所存在的障碍已经被攻克。我们将会在65nm和45/40nm之间采用有效率的、以价值为基础的设计流程。我们将乐于获得多CPU芯片和虚拟软件支持带来的优越性,凭借着新型设计平台的威力,迎来产品和应用新一轮的蓬勃发展。新型设计平台使设计公司可以充分发挥各种成本／功能／价值工艺节点之所长,满足当前市场上的定制需求。     

Thermoelectric quantum-dot superlattices with high ZT

Following the experimentally observed Seebeck coefficient enhancement in PbTe quantum wells in Pb_1−xEu_xTe/PbTe multiple-quantum-well structures which indicated the potential usefulness of low dimensionality, we have investigated the thermoelectric properties of PbSe_xTe_1−x/PbTe quantum-dot superlattices for possible improved thermoelectric materials. We have again found enhancements in Seebeck coefficient and thermoelectric figure of merit (ZT) relative to bulk values, which occur through the various physics and materials science phenomena associated with the quantum-dot structures. To date, we have obtained estimated ZT values approximately double the best bulk PbTe values, with estimated ZT as high as about 0.9 at 300 K.     

Biomimetic Hydroxyapatite–Drug Nanocrystals as Potential Bone Substitutes with Antitumor Drug Delivery Properties

This Full Paper investigates the adsorption and desorption of the anticancer drugs cis‐diamminedichloroplatinum(II) (CDDP, cisplatin) and the new platinum(II) complex di(ethylenediamineplatinum)medronate (DPM), as well as the clinically relevant bisphosphonate alendronate, towards two biomimetic synthetic HA nanocrystalline materials with either plate‐shaped (HAps) or needle‐shaped (HAns) morphologies and different chemico‐physical properties. The adsorption and desorption kinetics are dependent on the specific properties of the drugs and the morphology of the HA nanoparticles. Adsorption of the platinum complexes occurs with retention of the nitrogen ligands but the chloride ligands of cisplatin are displaced. Despite their opposite charges, the negatively charged alendronate bisphosphonate and the positively charged aquated cisplatin are strongly adsorbed, while the neutral DPM complex shows lower affinity towards the negatively charged apatitic surface. The data suggest that adsorption of the two platinum complexes is driven by electrostatic attractions, while interaction between the alendronate and the HA surface takes place by ligand exchange in which the two phosphonate groups of the drug molecule replace two surface phosphate groups. Significantly, adsorption of positively charged hydrolysis species of cisplatin is more favored on the phosphate‐rich HAns surface while adsorption of negatively charged alendronate is more favored on the calcium‐rich HAps surface. The latter type of short‐range electrostatic interactions also appear to dominate the desorption kinetics; consequently, drug release is greater for neutral DPM than for charged alendronate and aquated cisplatin. Moreover, while the release per unit area of charged species is the same for the two types of HAs, the release of DPM is faster from HAns, which is lower in surface calcium, than for HAps. Overall, this work demonstrates that the properties of HA nanocrystals can be modulated in such a way to produce HA/biomolecule conjugates tailored for specific therapeutic applications.     

3D Printed Stem‐Cell Derived Neural Progenitors Generate Spinal Cord Scaffolds

A bioengineered spinal cord is fabricated via extrusion‐based multimaterial 3D bioprinting, in which clusters of induced pluripotent stem cell (iPSC)‐derived spinal neuronal progenitor cells (sNPCs) and oligodendrocyte progenitor cells (OPCs) are placed in precise positions within 3D printed biocompatible scaffolds during assembly. The location of a cluster of cells, of a single type or multiple types, is controlled using a point‐dispensing printing method with a 200 µm center‐to‐center spacing within 150 µm wide channels. The bioprinted sNPCs differentiate and extend axons throughout microscale scaffold channels, and the activity of these neuronal networks is confirmed by physiological spontaneous calcium flux studies. Successful bioprinting of OPCs in combination with sNPCs demonstrates a multicellular neural tissue engineering approach, where the ability to direct the patterning and combination of transplanted neuronal and glial cells can be beneficial in rebuilding functional axonal connections across areas of central nervous system (CNS) tissue damage. This platform can be used to prepare novel biomimetic, hydrogel‐based scaffolds modeling complex CNS tissue architecture in vitro and harnessed to develop new clinical approaches to treat neurological diseases, including spinal cord injury.