Performance of decorrelating receivers in multipath Rician fading channels

This letter focuses on the performance analysis of the decorrelating receiver in multipath Rician faded CDMA channels. M-ary QAM scheme is employed to improve the spectral efficiency. Approximate expressions are first derived for the two performance indexes: the average symbol error rate (SER) and the average bit error rate (BER) when the decorrelating-first receiver perfectly knows the channel information of the user of interest. To achieve desirable closed-form expressions of the SER and the BER, we exploit results in large system analysis and make assumptions of a high signal-to-interference ratio (SIR) and/or a small Rician K-factor. To measure the receiver performance in the practical scenario, we further derive expressions to approximate the average SER and BER of the decorrelating-first scheme with channel uncertainty. Simulation results demonstrate that the analytical results can also be employed to evaluate the performance of the combining-first receiver.     

Dynamic light scattering studies on random cross-linking of polystyrene in semi-dilute solution

The random cross-linking of appropriately functionalized polystyrene in semi-dilute toluene solution (c = 0.01–0.05 g/mL) was studied by time-dependent measurements of dynamic light scattering. Macroscopic gelation occurred from concentrations as low as 0.02 g/mL. The gelation time, determined from the first appearance of fluctuations of the scattering intensity and the initial amplitude of the intensity correlation function (ICF), decreases markedly from about 100 min to 10 min with an increase of polymer concentration or cross-linker content. After the gel point, the ICFs display a characteristic power-law decay. The power-law exponent, n = 0.75 ± 0.06, does not change with (i) extent of reaction, (ii) polymer concentration, and (iii) cross-linker concentration, within the inspected ranges. This universal behavior is traced back to the fact that gelation took place as a result of random cross-linking of existent macromolecules, whose state of solution does not change markedly during conversion.     

Interlayer cooling potential in vertically integrated packages

The heat-removal capability of area-interconnect-compatible interlayer cooling in vertically integrated, high-performance chip stacks was characterized with de-ionized water as coolant. Correlation-based predictions and computational fluid dynamic modeling of cross-flow heat-removal structures show that the coolant temperature increase due to sensible heat absorption limits the cooling performance at hydraulic diameters ≤200 μm. An experimental investigation with uniform and double-side heat flux at Reynolds numbers ≤1,000 and heat transfer areas of 1 cm² was carried out to identify the most efficient interlayer heat-removal structure. The following structures were tested: parallel plate, microchannel, pin fin, and their combinations with pins using in-line and staggered configurations with round and drop-like shapes at pitches ranging from 50 to 200 μm and fluid structure heights of 100–200 μm. A hydrodynamic flow regime transition responsible for a local junction temperature minimum was observed for pin fin in-line structures. The experimental data was extrapolated to predict maximal heat flux in chip stacks having a 4-cm² heat transfer area. The performance of interlayer cooling strongly depends on this parameter, and drops from >200 W/cm² at 1 cm² and >50 μm interconnect pitch to <100 W/cm² at 4 cm². From experimental data, friction factor and Nusselt number correlations were derived for pin fin in-line and staggered structures.     

Nanoporous gold bumps for low temperature bonding

Nanoporous gold bumps have been deposited on silicon wafers by electroplating a silver–gold alloy followed by etching the silver. An open-porous cellular structure of gold at meso-scale is left on top of the bumps. For flip chip bonding we found low temperature and low force bonding conditions. The porous interconnects have very promising properties, like compressibility and reduced stiffness, which should result in higher bond yield and extended reliability.     

聚丙烯织物的涂料印花

涂料印花适用于各类纤维的染色。等离子处理可解决涂料印花用于聚丙烯织物时的色牢度问题，通过试验证明等离子处理的作用。     

Grundlegende Aspekte bei der Ultraschall-Prüfung von schallstreuenden Werkstoffen mit Signalen der CS-Technik

Basic Aspects to Improve Ultrasonic Signals by Means of the CS- Technique for Testing Coarse Grained Materials The influences of band width and centre frequency of ultrasonic pulses on the detection and evalution of defects in coarse grained materials are discussed. Theoretical calculations and experiments with artificial defects demonstrate the existence of optimum frequency ranges, within the transition range from reflection to scattering. By applying CS-pulses (controlled signals) these frequency ranges can be used in order to improve the signal-noise ratio. Guide-lines to optimize the pulses in ultrasonic testing of coarse grained materials are presented and discussed.     

Hydrocarbon Index – an algorithm for hyperspectral detection of hydrocarbons

Previous studies have shown that spectral signatures of hydrocarbon-bearing materials are characterized by prominent absorption features at 1.73 and 2.31?µm. Many other materials also show absorption features at wavelengths in the interval from 2.0 to 2.5?µm, yielding a mixed response in spectral signatures. In contrast to this wavelength range, most materials show similar spectral characteristics in the 1.73?µm range. Mainly hydrocarbon-bearing materials produce an absorption feature which is unique and prominent at 1.73?µm. A Hydrocarbon Index (HI) was developed and tested for the direct detection of hydrocarbons. The HI transforms multispectral data into a single image band that shows the distribution of hydrocarbons on the ground surface. The HI takes advantage of reflection differences around the 1.73?µm feature in hydrocarbon spectra. The HI indicates the presence of the 1.73?µm hydrocarbon absorption feature in a pixel spectrum. HI values can be easily calculated from radiance and reflectance data recorded by high signal-to-noise ratio hyperspectral scanners.     

Complex spreading sequences with a wide range of correlationproperties

This paper presents a new family of complex valued pseudo-random sequences for use in coded multiple access communication systems. The family offers a very wide range of values for both auto-correlation (AC) and cross-correlation (CC) functions, allowing great flexibility in the selection of characteristics of sequence sets. Based on the measure described in this paper for the mean-square aperiodic AC and CC values of a set of sequences, the correlation properties of sets of these sequences are compared to well-known sequence sets, and it is shown that sets from the new family of sequences have superior qualities. Tables of parameters for various sequence sets are presented to enable the construction and comparison of sets from this new family     

Adaptive Immune Responses in a Multiple Sclerosis Patient with Acute Varicella-Zoster Virus Reactivation during Treatment with Fingolimod

Fingolimod, an oral sphingosine 1-phosphate (S1P) receptor modulator, is approved for the treatment of relapsing forms of multiple sclerosis (MS). The interference with S1P signaling leads to retention particularly of chemokine receptor-7 (CCR7) expressing T cells in lymph nodes. The immunological basis of varicella zoster virus (VZV) infections during fingolimod treatment is unclear. Here, we studied the dynamics of systemic and intrathecal immune responses associated with symptomatic VZV reactivation including cessation of fingolimod and initiation of antiviral therapy. Key features in peripheral blood were an about two-fold increase of VZV-specific IgG at diagnosis of VZV reactivation as compared to the previous months, a relative enrichment of effector CD4+ T cells (36% versus mean 12% in controls), and an accelerated reconstitution of absolute lymphocytes counts including a normalized CD4+/CD8+ ratio and reappearance of CCR7+ T cells. In cerebrospinal fluid (CSF) the lymphocytic pleocytosis and CD4+/CD8+ ratios at diagnosis of reactivation and after nine days of fingolimod discontinuation remained unchanged. During this time CCR7+ T cells were not observed in CSF. Further research into fingolimod-associated VZV reactivation and immune reconstitution is mandatory to prevent morbidity and mortality associated with this potentially life-threatening condition.