Multiple-symbol trellis-coded modulation applied to noncoherentcontinuous-phase frequency shift keying

This paper considers a maximum-likelihood (ML) noncoherent detection scheme for multiple full response continuous-phase frequency shift keying (CPFSK) waveforms and introduces a trellis-coded modulation (TCM) scheme for this noncoherent modulation. By utilizing a Gaussian approximation for Rician random variables, we express the pairwise error probability as a function of the equivalent normalized squared distance (ENSD). ENSD plays the same role as normalized squared Euclidean distance when evaluating error probability performance for coherent detection. We derive an analytical approximation on the bit-error probability by employing ENSD for both the coded system and the uncoded system. For the uncoded system we show that the bit-error probability of noncoherent detection approaches that of coherent symbol-by-symbol detection in the limit as the multiplicity of the symbol goes to infinity for large signal-to-noise ratio (SNR), We determine specific optimal trellis encoders for binary and 4-ary CPFSK with modulation index 1/2 and 1/4, respectively, by application of Ungerboeck's (1982) set partitioning approach     

Stereoisomere Aromastoffe

Zusammenfassung Es werden Methoden zur racemisie-rungsfreien Stereodifferenzierung der 2-Methylbuttersäure (direkt bzw. nach Esterhydrolyse) aus Äpfeln und apfelhaltigen Lebensmitteln beschrieben. Die Enantiomerenverteilung der 2-Methylbuttersäure kann direkt an permethylierter-Cyclodextrinphase gaschromatogra-phisch bestimmt werden. Es wird stets hoher Enantiomerenüberschuß zugunsten des (S)-Isomeren der Säure nachgewiesen. Proben von naturidentischem und natürlichem (biotechnologisch hergestelltem) 2-Methyl-buttersäureethylester sowie Äpfel, Apfelsaft, Apfellikör, Calvados, Apfelwein, Apfelmarmelade und Joghurts mit Apfelzusatz werden untersucht. Ein Zusatz von naturidentischen, racemischen 2-Methylbuttersäureestern ist einfach nachweisbar.

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Stereoisomeric flavour compounds. XLII. Enantiomer distribution of 2-methylbutanoic acid in apples and apple-containing food

Summary The direct Stereodifferentiation of 2-methyl-butanoic acid and its esters (after hydrolysis) from apples and apple-containing food is described, using permethyl-ated-cyclodextrin as the chiral CGC phase. In all cases, high enantiomeric excess in favour of the (S)-enantiomer was ascertained. The method is applicable to apples, apple juice, apple liquor, calvados, apple wine, apple jam and apple-containing yoghurts. The addition of race-mic (nature-identical) esters may be easily detected.

     

A Bulk Acoustic Wave (BAW) Based Transceiver for an In-Tire-Pressure Monitoring Sensor Node

Attaching a tire pressure monitoring system (TPMS) on the inner liner of a tire allows sensing of important additional technical parameters, such as vehicle load or tire wearout. The maximum weight of the sensor is limited to 5 grams including package, power supply, and antenna. Robustness is required against extreme levels of acceleration. The node size is limited to about 1 cm3 to avoid high force-gradients due to device-deformation and finally, a long power supply lifetime must be achieved. In this paper a low-power FSK transceiver is presented. Exploiting BAW resonators the use of a bulky and shock-sensitive crystal and a PLL can be avoided. This makes the system more robust and radically reduces the start-up time to 2 ?s from few ms as in state-of-the-art crystal oscillator based systems. The current consumption of the transceiver is 6 mA in transmit mode with a transmit output power of 1 dBm and 8 mA in receive mode with a sensitivity of -90 dBm at a data rate of 50 kBit/s and a bit error rate of 10^-2. The transceiver ASIC and a microcontroller ASIC, a MEMS sensor, and a BAW die are arranged in a 3-D chip stack for best compactness, lowest volume, and highest robustness. The sensor node allows sensing of pressure, acceleration, supply voltage and temperature.     

Selective Functionalization of Microstructured Surfaces by Laser‐Assisted Particle Transfer

Microcavity arrays represent millions of different reaction compartments to screen, for example, molecular interactions, exogenous factors for cells or enzymatic activity. A novel method is presented to selectively synthesize different compounds in arrays of microcavities with up to 1 000 000 cavities per cm². In this approach, polymer microparticles with embedded pre‐activated monomers are selectively transferred into microcavities with laser radiation. After particle patterning, heating of the particle matrix simultaneously leads to diffusion and coupling of the monomers inside each microcavity separately. This method exhibits flexibility, not only in the choice of compounds, but also in the choice of particle matrix material, which determines the chemical reaction environment. The laser‐assisted selective functionalization of microcavities can be easily combined with the intensively growing number of laser applications for patterning of molecules and cells, which is useful for the development of novel biological assays.     

Electrical characteristics of low temperature-Al0.3Ga0.7As

In this work, we present electrical characterizations of n⁺ GaAs/low temperature (LT)-Al_0.3Ga_0.7As/n⁺ GaAs resistor structures in which the LT layers are grown at nominal substrate temperatures of 250 and 300°C. The resistivity and V_tfl parameters of these LT-Al_0.3Ga_0.7As layers are compared with those of LT-GaAs and Al_0.3Ga_0.7As grown at a normal growth temperature of 720°C. Low-temperature Al_0.3Ga_0.7As layers exhibit resistivities as high as 10¹² ohm-cm, nearly four orders of magnitude higher than that of LT-GaAs, and V_tfl values as high as 45 V, over twice that of LT-GaAs. We also find that the LT-Al_0.3Ga_0.7As materials grown at 250 and 300°C appear to show opposite and contradictory trends with respect to resistivity and V_tfl. We propose that this result can be explained by residual hopping conduction in the 250°C material. Temperature dependent conductivity measurements confirm the presence of a hopping mechanism in LT-Al_0.3Ga_0.7As grown at 250°C and yield activation energies of 0.77 and 0.95 eV for LT-GaAs and LT-Al_0.3Ga_0.7As, respectively.     

Semiconductor laser amplifier as optical switching gate

The properties of a semiconductor laser amplifier as optical switching gate are investigated. Particular attention is paid to gain, contrast ratio, and switching time of the device. These properties are studied experimentally and theoretically with respect to the injection current, optical input power, and cavity resonances. The experimental arrangements and the theoretical method are described. As an example of the various applications of semiconductor laser amplifier gates, packet switching experiments with self-routing, employing cascaded switching gates, are reported. In a theoretical analysis the restrictions that the properties of semiconductor laser amplifier gates impose on a larger switching system consisting of many such gates are investigated     

Dynamic effects in hot-carrier degradation relevant for CMOS operation

We describe different dynamic degradation effects in n- and p-MOSFETs as they are clearly proven and generally accepted to date. It turns out that they are connected with time constants in the oxide and at the interface and that time constants related to the device operation are too short to be relevant in this context. The effects are detrapping of fixed charges, the slow movement of holes in the oxide, an enhanced-degradation effect caused by alternating voltage conditions, during dynamic stress, and a post-stress interface state formation effect in nitride passivated n-MOSFETs. Furthermore, we discuss the relevance of those effects, under different operation conditions, finding that the fast non-stationary effects are of little significance. Only the “slow” effects, with time constants of seconds and above, play a role in reliability issues of MOSFETs.     

Modeling of static concentrator modules incorporating lambertian or v-groove rear reflectors

Ray tracing modeling has been used to calculate the performance of static concentrator modules with a geometric concentration ratio of 2 and incorporating very narrow (1–2 mm), long and bifacial cells. The modules utilize either a v-groove or a lambertian rear reflector. It is shown that the use of very narrow cells allows a performance improvement of 5% or more compared to structures incorporating wider cells, in the case of v-groove reflectors. The averaged yearly performance for both types of reflectors is found to be rather similar, with expected light collection in the range 82–86% of that of a module with 100% cell coverage. Experimental measurements on modules with lambertian reflectors are shown to be in good agreement with the results of modeling.     

Carbohydrate content of apolipoprotein B-48 from rat chylomicrons of varying density

Monosaccharide composition was determined in apolipoprotein B-48 (apoB) of chylomicrons of rat mesenteric lymph. Chylomicrons were separated into three fractions based on density. Triglyceride and apolipoprotein content were determined in each. ApoB was isolated and quantified using precipitation with isopropanol. Chylomicrons were collected in lymph under normal conditions, and with Poloxalene 2930 when chylomicron secretion was inhibited. Most of the triglyceride was carried in the least dense fraction, while the highest apoB content was in the most dense fraction under normal conditions. Mannose and galactosamine contents of apoB were similar in all fractions while contents of both glucosamine and galactose were highest in the least dense fraction. When chylomicron secretion was inhibited by Poloxalene, the amount of triglyceride recovered in the least dense fraction was significantly reduced. Despite the inhibition of lipid transport in the least dense fraction of chylomicrons by Poloxalene, there was little change in apoB recoveries and in the relative content of various monosaccharides in the apoB from each of the three fractions as compared to results obtained during lipid absorption under normal conditions. In conclusion, carbohydrate composition of apoB of chylomicrons is heterogeneous and varies with chylomicron density.     

Lebensmittelkontaminationen im Emissionsbereich Chemischer Reinigungen

Zusammenfassung Lebensmittel, die im Emissionsbereich Chemischer Reinigungen gelagert bzw. verkauft werden, können erheblich mit Tetrachlorethen belastet sein. Hohe Tetrachlorethengehalte wurden sowohl in Lebensmittelproben aus über Chemischen Reinigungen gelegenen Wohnungen als auch in Proben aus dem Lebensmitteleinzelhandel festgestellt. Lebensmittel mit hohem Fettgehalt wiesen stets die höchsten Kontaminationen auf.

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Contamination of foodstuffs by emissions from dry cleaning units

Summary Tetrachloroethene (perchloroethylene) from dry-cleaning units may contaminate adjacent flats in the same building. Increased concentrations of tetrachloroethene have been found in foodstuffs in homes situated above dry cleaning units and in foodstuffs from groceries located neat drycleaning units. The concentrations were extremely high in foods rich in fat.