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A micro-tubular solid oxide fuel cell stack model including an integrated cooling system was developed using a quasi three-dimensional, spatially resolved, transient thermodynamic, physical and electrochemical model that accounts for the complex geometrical relations between the cells and cooling-tubes. For the purpose of model evaluation, reference operating, geometrical and material properties are determined. The reference stack design is composed of 3294 cells, with a diameter of 2 mm, and 61 cooling-tubes. The stack is operated at a power density of 300 mW/cm2 and air is used as the cooling fluid inside the integrated cooling system. Regarding the performance, the reference design achieves an electrical stack efficiency of around 57% and a power output of 1.1 kW. The maximum occurring temperature of the positive electrode electrolyte negative electrode (PEN)-structure is 1369 K. As a result of a design of experiments, parameters of a best-case design are determined. The best-case design achieves a comparable power output of 1.1 kW with an electrical efficiency of 63% and a maximum occurring temperature of the PEN-structure of 1268 K. Nevertheless, the best-case design has an increased volume based on the higher diameter of 3 mm and increased spacing between the cells.

This letter presents a 220–261-GHz frequency multiplier-by-18 chain in a 130-nm SiGe BiCMOS technology. It consists of three amplifiers (12–15, 110–135, and 216–270 GHz), two frequency triplers (36–45 and 108–135 GHz), a third-order Chebyshev bandpass filter (36–45 GHz), and a modified Gilbert-cell-based frequency doubler (216–270 GHz). The peak output power is about 8 dBm at 240 GHz with a 3-dB bandwidth of 41 GHz for an input power of −7 dBm. The unwanted harmonics are suppressed more than 25 dBc over the frequency range of interest. It consumes a dc current of 114.7 mA from a supply voltage of 3.3 V in the quiescent operation and drains a current of 130 mA for an input power of −7 dBm, which results in a drain efficiency of 1.47%. The total circuit occupies an area of 0.58 mm 2 (1.35 mm $\times0.43$ mm). [ABSTRACT FROM AUTHOR]

This letter reports a compact-size 225–265 GHz quadrature receiver (RX), consisting of a low-noise amplifier (LNA), a power divider (PD), two down-conversion fundamental mixers, and an IQ generator, in a 130-nm SiGe BiCMOS technology with $f_{T}/f~_{\text {max}}$ of 300/500 GHz. The measured peak value of the down-conversion power gain is 20.6 dB at 240 GHz without IF amplification, and it achieves a 3-dB RF bandwidth of 40 GHz from 225 to 265 GHz. The measured minimum single-sideband (SSB) noise figure (NF) is 13.2 dB at 240 GHz and better than 14.2 dB along the 3-dB RF bandwidth. The amplitude and phase imbalances of the IF output signals were measured as less than 1.7 dB and 2°, respectively, over the frequency range of interest. The RX circuit draws a current of about 40.5 mA from a single-supply of 3.3 V. It occupies a total area of 0.42 mm 2 (0.97 mm $\times $ 0.43 mm), and the effective area is about 0.14 mm 2, excluding the pads and Marchand baluns placed for on- wafer probing. [ABSTRACT FROM AUTHOR]

We present a 2.5-GHz voltage-controlled oscillator (VCO) with eight equally distributed phases derived from a 10-GHz LC VCO. Stochastic and static phase errors were obtained by spectrum analyzer measurements in conjunction with an on-chip single-sideband mixer. From the measured phase noise spectrum, we predict an absolute rms jitter contribution of 130 fs in a 2-MHz bandwidth phase-locked loop. A static phase error of less than 0.7[degrees] was deduced from the sideband suppression. The eight-phase VCO is tunable from 2.35 to 2.85 GHz and draws 16 mA from a 2.0-V supply. Possible applications include clock and data recovery of a 10-Gb/s signal in a fiber-optic receiver as well as high-precision image rejection receivers and I/Q direct up-converters for radio-frequency applications. Index Terms--Clock and data recovery (CDR), oscillator, quarter-rate sampling, timing jitter.

In this paper, a packaging solution for millimeter-wave system-on-chip (SoC) radio transceivers is presented. The on-chip antennas are realized as primary radiators of an integrated lens antenna which offer high bandwidth and high efficiency. The package concept includes a high permittivity silicon lens which serves additionally as heat sink and a quad flat no-lead package which is mountable on a standard printed circuit board (PCB). The electrical and thermal properties of the package are investigated through simulations and calibrated measurements. The concept is verified by realizing a complete radar sensor. The manufactured SoC radar frontend is soldered on a standard PCB which includes the baseband circuitry for a frequency-modulated continuous wave radar and finally, measurements are performed to compare the superposed radiation patterns of the transmit and receive antennas with simulations. [ABSTRACT FROM AUTHOR]

In this paper, a high-range 60-GHz monostatic transceiver system suitable for frequency-modulated continuous-wave (FMCW) applications is presented. The RF integrated circuit is fabricated using a 0.13- \mu \textm SiGe BiCMOS technology with fT / f\max of 250/340 GHz and occupies a very compact area of $1.42 \times 0.72$ mm2. All of the internal blocks are designed fully differential with an in-phase/quadrature receiver (RX) conversion gain of 14.8 dB and −18.2 dBm of input-referred 1-dB compression point and a transmitter (TX) with 6.4 dBm of output power. The 60-GHz voltage-controlled oscillator is of a push-push type Colpitts oscillator integrated into a frequency divider with an output frequency between 910 MHz and 1 GHz with the help of 3-bit frequency tuning mechanism for external phase-locked loop operations. Between the TX and RX channels, a tunable coupler is placed to guarantee a high isolation between channels which could withstand any fabrication failures and provide a single differential antenna output. On the TX side, two power detectors are placed in order to monitor the transmitted and reflected powers on the TX channel by passing through a branch-line coupler for built-in-self-test purposes. The total current consumption of this transceiver is 156 mA at 3.3 V of single supply. Considering the successful real-time radar measurements, which the radar is able to detect the objects in more than 90-m range, it proves the suitability of this monostatic chip in high-range FMCW radar systems. [ABSTRACT FROM PUBLISHER]

Increasing demand for industrial radars has spurred research aimed toward designing better transceiver (TRx) integrated circuits (ICs) combined with advanced packaging technologies [1]-[6], innovative antenna concepts, very precise wirebonding schemes [5]-[8], and high-performance baseband processing systems [9]. With a well-optimized package of such products, the resulting application fields can vary from avionics and robotics to automotive, monitoring, level-tracking, and vital-sign-detection systems, among many others. All these applications will require that the final product satisfy certain metrics such as range, resolution, accuracy, power consumption, and (as always) production cost, which is ultimately the most crucial criterion. [ABSTRACT FROM PUBLISHER]

A highly miniaturized and commercially available millimeter wave (mmw) radar sensor working in the frequency range between 121 and 127 GHz is presented in this paper. It can be used for distance measurements with an accuracy in the single-digit micrometer range. The sensor is based on the frequency modulated continuous wave (CW) radar principle; however, CW measurements are also possible due to its versatile design. An overview of the existing mmw radar sensors is given and the integrated radar sensor is shown in detail. The radio frequency part of the radar, which is implemented in SiGe technology, is described followed by the packaging concept. The radar circuitry on chip as well as the external antennas is completely integrated into an 8 mm $\times \,\, 8$ mm quad flat no leads package that is mounted on a low-cost baseband board. The packaging concept and the complete baseband hardware are explained in detail. A two-step approach is used for the radar signal evaluation: a coarse determination of the target position by the evaluation of the beat frequency combined with an additional determination of the phase of the signal. This leads to an accuracy within a single-digit micrometer range. The measurement results prove that an accuracy of better than \pm 6~\mu \text{m} can be achieved with the sensor over a measurement distance of 35 mm. [ABSTRACT FROM AUTHOR]

The dynamic range of frequency modulated continuous wave (FMCW) radar sensors is often limited by the phase noise of the ramp signal. Especially at millimeter wave (mm-wave) frequencies, a low phase noise signal is very difficult to obtain. In this paper, a new system architecture, which is implemented in a low-cost, ultracompact FMCW radar monolithic microwave integrated circuit (MMIC) at 160 GHz, is proposed to address this topic. The approach is based on a frequency offset synthesizer, whose upconverting mixer is driven by a stabilized low phase noise local oscillator (LO) signal. This LO is generated by a fixed-frequency phase locked loop with a 2^N divider. The upconversion of the ramp signal with the stabilized LO signal leads to an excellent mm-wave phase noise of −89 dBc/Hz at a frequency offset of 1 MHz. By integrating the antennas on the MMIC, interconnects at mm-wave frequencies to package or printed circuit board are avoided and a simple assembly and interconnection technology is feasible. The ultracompact MMIC is realized on an area of only 2 mm2, including the integrated antennas. A precision below 5 \mu \textm for range measurements is demonstrated with the radar sensor. Additionally, the radar performance is evaluated with two different voltage-controlled oscillators for the generation of the ramp signal. [ABSTRACT FROM AUTHOR]

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The ideal MALDI/LDI mass spectrometry sample target for an axial TOF instrument possesses a variety of properties. Primarily, it should be chemically inert to the sample, i.e. analyte, matrix and solvents, highly planar across the whole target, without any previous chemical contact and provide a uniform surface to facilitate reproducible measurements without artifacts from previous sample or matrix compounds. This can be hard to achieve with a metal target, which has to be extensively cleaned every time after use. Any cleaning step may leave residues behind, may change the surface properties due to the type of cleaning method used or even cause microscopic scratches over time hence altering matrix crystallization behavior. Alternatively, use of disposable targets avoids these problems. As each possesses the same surface they therefore have the potential to replace the conventional full metal targets so commonly employed. Furthermore, low cost single-use targets with high planarity promise an easier compliance with GLP guidelines as they alleviate the problem of low reproducibility due to inconsistent sample/matrix crystallization and changes to the target surface properties. In our tests, polymeric metal nano-coated targets were compared to a stainless steel reference. The polymeric metal nano-coated targets exhibited all the performance characteristics for a MALDI MS sample support, and even surpassed the – in our lab commonly used – reference in some aspects like limit of detection. The target exhibits all necessary features such as electrical conductivity, vacuum, laser and solvent compatibility. [ABSTRACT FROM AUTHOR]

Different types of bondwire interconnect for differential chip-to-antenna and single-ended chip-to-chip interfaces are investigated. Two differential compensation structures for various lengths of interconnects are designed and experimentally evaluated using dedicated transmit and receive radar modules operating across a 110–156 GHz band. Measurement results demonstrate that a fractional bandwidth of 7.5% and a minimum insertion loss of 0.2 dB can be achieved for differential interconnects as long as 0.8 mm. Design and measurement results of an extremely wideband low-loss single-ended chip-to-chip bondwire interconnect that features 1.5 dB bandwidth from DC to 170 GHz and insertion loss of less than 1 dB at 140 GHz are presented as well. The results show that the well-established wire-bonding techniques are still an attractive solution even beyond 100 GHz. Reproducibility and scalability of the proposed solutions are assessed as well. [ABSTRACT FROM PUBLISHER]

Commonly used methods for size and shape analysis of bionanoparticles found in vaccines like X-ray crystallography and cryo-electron microscopy are very time-consuming and cost-intensive. The nano-electrospray (nanoES) gas-phase electrophoretic mobility macromolecular analyzer (GEMMA), belonging to the group of ion mobility spectrometers, was used for size determination of vaccine virus particles because it requires less analysis time and investment (no vacuum system). Size exclusion chromatography (SEC) of viral vaccines and production intermediates turned out to be a good purification/isolation method prior to GEMMA, TEM (transmission electron microscopy) and AFM (atomic force microscopy) investigations, as well as providing a GEMMA analysis-compatible buffer. Column materials and different elution buffers were tested for optimal vaccine particle yield. We used a Superdex 200 column with a 50 mM ammonium acetate buffer. In addition, SEC allowed the removal of process-related impurities from the virions of interest. A sample concentrating step or a detergent addition step was also investigated. As a final step of our strategy SEC-purified or untreated vaccine-nanoparticles were further analyzed: (a) by immunological detection with a specific polyclonal antibody (dot blot) to verify the biological functionality, (b) by GEMMA to provide the size of the particles at atmospheric pressure and (c) by AFM and (d) TEM to obtain both size and shape information. The mean diameter of inactivated tick-borne encephalitis virions (i.e. vaccine particles) determined by GEMMA measurement was 46.6 ± 0.5 nm, in contrast to AFM and TEM images providing diameters of about 58 ± 4 and 52 ± 5 nm, respectively. [ABSTRACT FROM AUTHOR]

This paper shows the antenna design of an integrated 122-GHz radar sensor. The sensor consists of a SiGe IC with a complete radar circuit and two antennas for transmitting and receiving the 122-GHz signal. The IC and the antennas are integrated into a low-cost plastic package that is assembled using wire bond technology. The antenna design was specifically optimized regarding the integration into the package and the compensation of the parasitic effects of the wire bond interconnect. First, the antenna design and its novel feeding technique based on a GCPW transmission line are explained. Then, measurement results including the wire bond interconnect are presented. Finally, details of the complete radar sensor are given. [ABSTRACT FROM PUBLISHER]

Fusarium is a widespread genus of filamentous fungi and a member of the soil microbial community. Certain subspecies are health threatening because of their mycotoxin production that affects the human and animal food chain. Thus, for early and effective pest control, species identification is of particular interest; however, differentiation on the subspecies level is challenging and time-consuming for this fungus. In the present study, we show the possibilities of intact cell mass spectrometry for spore analysis of 22 different Fusarium strains belonging to six Fusarium subspecies. We found that species differentiation is possible if mass spectrometric analyses are performed under well-defined conditions with fixed parameters. A critical point for analysis is a proper sample preparation of spores, which increases the quality of mass spectra with respect to signal intensity and m/z value variations. It was concluded that data acquisition has to be performed automatically; otherwise, user-specific variations are introduced generating data which cannot fit the existing datasets. Data that show clearly that matrix-assisted laser desorption ionization-based intact cell/intact spore mass spectrometry (IC/ISMS) can be applied to differentiate closely related Fusarium spp. are presented. Results show a potential to build a database on Fusarium species for accurate species identification, for fast response in the case of infections in the cornfield. We furthermore demonstrate the high precision of our approach in classification of intact Fusarium species according to the location of their collection. [ABSTRACT FROM AUTHOR]

Abstract: The necessary reduction of the human footprint demanded by Sustainable Development can be measured by the entropy flow of the society to the environment. The classic tools of process evaluation as e.g. exergetic or life cycle analysis are able to evaluate existing solutions. But their use during the design phase is quite limited because of lacking information about the system and its components. They may be helpful for evolutionary development strategies on a long term only. But reversible process structures can be used as benchmarks already in the conceptual design phase to introduce the demands of the second law. It can be shown that basic human demands on housing, mobility, communication, and infrastructure and industry can be principally supplied by reversible process structures. Because the process logic is a virtual one, real processes can be engineered with a reversible structure however its components produce irreversible entropy flows. Hybrid cars are the most common examples here. The use of exergetic efficiencies allows a transfer of the results of reversible structures to real technology easily. The here presented methodology of sustainable engineering can be summarized by three design rules as using reversible structures, considering technology by exergetic efficiencies, and minimizing components’ entropy export. The still increasing utilization of electricity in upcoming technologies is very helpful for introducing reversible structures within hybrid technologies. [Copyright &y& Elsevier]

A 0.13 µm SiGe BiCMOS technology for millimeter-wave applications is presented. This technology features high-speed HBTs with peak transit frequencies fτ of 240 GHz, maximum oscillation frequencies fmax of 330 GHz, and break-down voltages BVCEO of 1.7 V along with high-voltage HBTs (fτ = 50 GHz, fmax = 130Hz, BVCEO = 3.7 V) integrated in a dual gate oxide RF-CMOS process. Ring oscillator gate delays of 2.9 ps, low-noise amplifiers for 122 GHz, and LC oscillators with fundamental-mode oscillation frequencies above 200 GHz are demonstrated. [ABSTRACT FROM AUTHOR]

The iterative design of an integrated subharmonic receiver for 120-127 GHz is presented. The receiver consists of a single-ended low-noise amplifier (LNA), a push-push voltage-controlled oscillator (VCO) with 1/32 divider, a polyphase filter, and a subharmonic mixer. The receiver is fabricated in SiGe:C BiCMOS technology with fτ/fmax of 255 GHz/315 GHz. In the first design the differential down-conversion gain of the receiver is 25 dB at 127 GHz, and the corresponding noise figure (NF) is 11 dB. The 3 dB bandwidth reaches from 125 GHz to 129 GHz. The input 1 dB compression point is at -40 dBm. The receiver draws 139 mA from a supply voltage of 3.3 V. A subsequent design demonstrates 31 dB differential gain at 122 GHz, and 11 dB NF. The 3 dB bandwidth is from 121 GHz to 124 GHz. The receiver has a NF of 8 dB for 3 GHz IF frequency due to integrated RF bandpass-filtering. It is realized by the lower NF of the LNA, and the LNA itself. [ABSTRACT FROM AUTHOR]

We present a measured current-mode logic ring oscillator gate delay of 2.3 ps, a record for digital circuits in silicon-based technologies. This result was achieved in a silicon--germanium (SiGe) heterojunction bipolar transistor (HBT) technology operating at 25 K. In addition to higher cutoff frequency and lower collector-base capacitance, lower base resistance is also responsible for the improved switching speed at cryogenic temperatures. The self-heating characteristics of these SiGe HBT circuits are also investigated across temperatures. [ABSTRACT FROM AUTHOR]

A single-ended 77/79 GHz monolithic microwave integrated circuit (MMIC) receiver has been developed in SiGe HBT technology for frequency-modulated continuous-wave (FMCW) automotive radars. The single-ended receiver chip consists of the first reported SiGe 77/79 GHz single-ended cascode low noise amplifier (LNA), the improved single-ended RF double-balanced down-conversion 77/79 GHz micromixer, and the modified differential Colpitts 77/79 GHz voltage controlled oscillator (VCO). The LNA presents 20/21.7 dB gain and mixer has 13A/7 dB gain at 77/79 GHz, and the VCO oscillates from 79 to 82 GHz before it is tuned by cutting the transmission line ladder, and it centres around 77 GHz with a tuning range of 3.8 GHz for the whole ambient temperature variation range from -40°C to +125°C after we cut the lines by tungsten-carbide needles. Phase noise is -90 dBc/Hz@1 MHz offset. Differential output power delivered by the VCO is 5 dBm, which is an optimum level to drive the mixer. The receiver occupies 0.5 mm² without pads and 1.26 mm² with pads, and consumes 595 mW. The measurement of the whole receiver at 79 GHz shows 20-26 dB gain in the linear region with stable IF output signal. The input P1dB of the receiver is -35 dBm. [ABSTRACT FROM AUTHOR]

A highly sensitive 120 GHz integrated dielectric sensor in SiGe BiCMOS with back-side etching is presented. The sensor consists of a bandpass filter using a planar resonator, a 120 GHz VCO at the input, and a power detector at the output. The sensitivity of the stand-alone resonator and the sensor was tested by measuring the change in the detector output voltage and the shift in the frequency response of the resonator due to a dielectric sample placed over the resonator. Simulated and measured performance of the developed device are presented and discussed. [ABSTRACT FROM PUBLISHER]

Knowledge about the extent of total variation experienced between samples from different individuals is of great importance for the design of not only proteomics but every clinical study. This variation defines the smallest statistically significant detectable signal difference when comparing two groups of individuals. We isolated platelets from 20 healthy human volunteers aged 56-100 years because this age group is most commonly encountered in the clinics. We determined the technical and total variation experienced in a proteome analysis using two-dimensional DIGE with IPGs in the pI ranges 4-7 and 6-9. Only spots that were reproducibly detectable in at least 90% of all gels (n = 908) were included in the study. All spots had a similar technical variation with a median coefficient of variation (cv) of about 7%. In contrast, spots showed a more diverse total variation between individuals with a surprisingly low median cv of only 18%. Because most known biomarkers show an effect size in a 1-2-fold range of their cv, any future clinical proteomics study with platelets will require an analytical method that is able to detect such small quantitative differences. In addition, we calculated the minimal number of samples (sample size) needed to detect given protein expression differences with statistical significance.

Glutamine (Gln) utilising cells suffer from Gln-starvation during critical illness when plasma Gln levels are decreased. This study investigates whether such cells activate adaptive mechanisms. Monocytic U937 cells were cultured at 0.6 and 0.2 mM Gln for up to four days. Within the first day a decrease of ATP (78% of control), intracellular free Gln (13%), Hsp70 (74%) and proliferation rate (79%) was observed. A prolonged culture at 0.6 mM Gln for additional three days led to a recovery of ATP (97%), Hsp70 (91%) and proliferation (92%). The intracellular free Gln increased only to 41%. At 0.2 mM Gln, however, all levels remained decreased. The activation of the metabolic sensor AMP activated kinase (AMPK) increased immediately in Gln-starving cells but regained normal values only in cells cultured at 0.6 mM. A proteomic analysis identified 23 proteins, which were affected by Gln starvation including metabolic enzymes, proteins involved in synthesis and degradation of RNA and proteins, and stress proteins. These data show that Gln-utilising cells activate adaptive mechanisms in response to Gln-starvation, which enable them to overcome a Gln shortage. At very low Gln concentrations, these adaptive mechanisms are not sufficient to countervail the lack of the amino acid.

For the preparation of proteins for proteome analysis, precipitation is frequently used to concentrate proteins and to remove interfering compounds. Various methods for protein precipitation are applied, which rely on different chemical principles. This study compares the changes in the protein composition of human blood platelet extracts after precipitation with ethanol (EtOH) or trichloroacetic acid (TCA). Both methods yielded the same amount of proteins from the platelet preparations. However, the EtOH-precipitated samples had to be dialyzed because of the considerable salt content. To characterize single platelet proteins, samples were analyzed by two-dimensional fluorescence differential gel electrophoresis. More than 90% of all the spots were equally present in the EtOH- and TCA-precipitated samples. However, both precipitation methods showed a smaller correlation with nonprecipitated samples (EtOH 74.9%, TCA 79.2%). Several proteins were either reduced or relatively enriched in the precipitated samples. The proteins varied randomly in molecular weight and isoelectric point. This study shows that protein precipitation leads to specific changes in the protein composition of proteomics samples. This depends more on the specific structure of the protein than on the precipitating agent used in the experiment.