The BLIXER, a Wideband Balun-LNA-I/Q-Mixer Topology

This paper proposes to merge an I/Q current-commutating mixer with a noise-canceling balun-LNA. To realize a high bandwidth, the real part of the impedance of all RF nodes is kept low, and the voltage gain is not created at RF but in baseband where capacitive loading is no problem. Thus a high RF bandwidth is achieved without using inductors for bandwidth extension. By using an I/Q mixer with 25% duty-cycle LO waveform the output IF currents have also 25% duty-cycle, causing 2 times smaller DC-voltage drop after IF filtering. This allows for a 2 times increase in the impedance level of the IF filter, rendering more voltage gain for the same supply headroom. The implemented balun-LNA-I/Q-mixer topology achieves > 18 dB conversion gain, a flat noise figure < 5.5 dB from 500 MHz to 7 GHz, IIP2 = +20 dBm and IIP3 = -3 dBm. The core circuit consumes only 16 mW from a 1.2 V supply voltage and occupies less than 0.01 mm2 in 65 nm CMOS

A wideband noise-canceling CMOS LNA exploiting a transformer

A broadband LNA incorporating single-ended to differential conversion, has been successfully implemented using a noise-canceling technique and a single on-chip transformer. The LNA achieves a high voltage gain of 19dB, a wideband input match (2.5-4.0 GHz), and a noise figure of 4-5.4 dB, while consuming only 8mW. The LNA is implemented in a 90nm CMOS process with 6 metal layers

Wideband CMOS receivers exploiting simultaneous output balancing and noise/distortion canceling

Abstract— This paper deals with the problem of realizing wideband receiver front-ends in downscaled CMOSTechnologies, which are highly wanted for multi-standard radio receivers and cognitive radio applications. Instead of using many narrowband inductor based receivers, we prefer the use of one wideband receiver with sufficient bandwidth to cover all popular frequency bands up to 6GHz or even 10GHz. To relax RF filter requirements, high linearity is required, while high gain and low noise are important for good sensitivity. Downscaled CMOS technologies feature high speed transistors, but also decreasing supply voltages and increasing transistor non-idealities, which makes it increasingly difficult to achieve high gain and good linearity. It will be shown that a combination of a common-gate (CG) stage and an admittance-scaled common-source (CS) stage has attractive properties for implementing a wideband receiver with active balun, while simultaneously canceling the noise and distortion of the CG-stage. Example applications in a wideband Balun-LNA and combined Balun-LNA-Mixer will be shown

Infochemicals in a tritrophic system : interactions between Brassica, Pieris and Cotesia

In this thesis the isolation and identification of infochemicals which are involved in Cotesia-Pieris-Brassica relationships with the prospect of their eventual use in cabbage crop protection, are described. The study focuses on two topics: regulation of Pieris oviposition behaviour and host selection behaviour of parasitoids of Pieris larvae.A general introduction about relationships between plants/insects and insects/insects, and more specifically the relationship between Crucifers and their associated insect herbivores as well as phytochemical information about Cruciferae is given in chapter 1.In chapter 2 the isolation and identification of the oviposition stimulant for the large cabbage white butterfly, present in the leaf surface of Brussels sprout plants, is described. The oviposition stimulant could be identified as glucobrassicin (3-indolyl-methyl-glucosinolate), a secondary plant compound belonging to the glucosinolates which are characteristic for the genus Brassica.The identification of oviposition deterrents from the eggs of the large cabbage white is described in chapter 3. Three compounds, responsible for the oviposition deterring activity of an egg wash when sprayed onto a cabbage leaf, were isolated and identified as trans -2-[3-(3,4,5-trihydroxy- phenylpropenoyl)-amino]-3,5-dihydroxy-benzoic acid (miriamide), trans -2-[3-(3,4-dihydroxyphenylpropenoyl)amino]-3,5-dihydroxybenzoic acid and trans -2-[3-(3,4-dihydroxy-5-β- glucopyranose-phenylpropenoyl)amino]-3,5-dihydroxybenzoic acid. The synthesis of the first two compounds is also described. The three previously unknown avenanthramide alkaloids (amides of derivatives of anthranilic and cinnamic acid) form a group of compounds that have not been reported from the animal kingdom before.The structure-activity relationship of the isolated avenanthramide alkaloids (described in chapter 3) and eight related synthesized compounds, as oviposition deterrents for P.brassicae L., is studied in chapter 4. For ten of the tested compounds, the effective dosis at which an oviposition deterring index of 50 % (ED 50 ) occurred, has been calculated. At least three groups with different activity levels were found. Changes in the way both ring systems were connected had no influence on the deterrent activity, while modifications of groups linked to the anthranilic part of the molecule led to a reduction of activity compared to miriamide. Mono- and dihydroxy substituted cinnamic parts of the molecule increased its effectiveness. trans -(4-Hydroxyphenylpropenoyl)amino]-3,5-dihydroxybenzoic acid was found to be significantly more active than miriamide.In chapter 5, the question whether ovipositing female butterflies, after landing on the upper surface of a cabbage leaf, can perceive the host marking pheromone (HMP) present on the eggs deposited on the lower side of the leaf is studied. The strongly oviposition deterring avenanthramide alkaloids could not be detected in leaf surface extracts from leaves from which egg batches had been removed. Thus the isolated avenanthramide alkaloids are not directly responsible for the HMP effect. Evidence is obtained that cabbage leaves themselves produce oviposition deterrents in response to oviposited egg batches, thus making the use of the terni HMP disputable. Fractions containing potent oviposition deterrents were isolated from surface extract of leaves from which previously laid egg batches had been removed.In chapter 6 headspace analysis of intact cabbage plants and cabbage plants infested with larvae of the small cabbage white and the large cabbage white is described. The volatile production of intact cabbage plants shows a seasonal fluctuation with the highest production rate in the summer period.Major differences in the headspace profile of intact and caterpillar damaged plants were revealed for hexyl acetate, cis -3-hexenyl acetate, myrcene, sabinene and 1,8-cineole. No significant quantitative differences were found between the headspace of cabbage plants infested by one or the other caterpillar species. In a windtunnel bioassay (dual-choice), it was found that the solitary parasitoid of the small cabbage white and a gregarious parasitoid of the large cabbage white distinguish between intact cabbage plants and cabbage plants infested with their preferred hosts

An in-line dye tracer experiment to measure the residence time in continuous concrete processing

This paper introduces an in-line dye tracer experiment to measure the residence time functions in continuous concrete processing. These functions quantify the material-system interdependency and can be used to compare different material-system combinations and for quality and process control. A Rhodamine B solution was used as the tracer material and detected by measuring the color intensity using a digital image processing technique. The experiment was validated on a 3D concrete printing system by comparing the results of impulse, step-up and step-down inputs with different tracer quantities. The results show that a high signal-to-noise ratio can be obtained with low tracer concentrations. For the examined combination of material and system, an impact on the original process was only observed for the step-up inputs at high tracer quantities. It is concluded that the presented method is cost-effective and non-labor-intensive and, therefore, has the potential for wide adoption and integration in automated workflows

Neutral and Charged Polymers at Interfaces

Chain-like macromolecules (polymers) show characteristic adsorption properties due to their flexibility and internal degrees of freedom, when attracted to surfaces and interfaces. In this review we discuss concepts and features that are relevant to the adsorption of neutral and charged polymers at equilibrium, including the type of polymer/surface interaction, the solvent quality, the characteristics of the surface, and the polymer structure. We pay special attention to the case of charged polymers (polyelectrolytes) that have a special importance due to their water solubility. We present a summary of recent progress in this rapidly evolving field. Because many experimental studies are performed with rather stiff biopolymers, we discuss in detail the case of semi-flexible polymers in addition to flexible ones. We first review the behavior of neutral and charged chains in solution. Then, the adsorption of a single polymer chain is considered. Next, the adsorption and depletion processes in the many-chain case are reviewed. Profiles, changes in the surface tension and polymer surface excess are presented. Mean-field and corrections due to fluctuations and lateral correlations are discussed. The force of interaction between two adsorbed layers, which is important in understanding colloidal stability, is characterized. The behavior of grafted polymers is also reviewed, both for neutral and charged polymer brushes.Comment: a review: 130 pages, 30 ps figures; final form, added reference

Lack of genetic structure in greylag goose (Anser anser) populations along the European Atlantic flyway

Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those fromScandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout the European Atlantic flyway, from breeding sites in Norway and the Netherlands to stopover and wintering sites in northern and south-western France. The mtDNA marker (CR1 D-Loop, 288 bp sequence, 144 ind.) showed 23 different haplotypes. The genetic distances amongst individuals sampled in Norway, northern France and the Netherlands were low (range 0.012–0.013). Individuals in south-western France showed a slightly higher genetic distance compared to all other sampling areas (ranges 0.018–0.022). The NJ tree does not show evidence of any single clades grouping together all individuals fromthe same geographic area. Besides, individuals from each site are found in different branches. Bayesian clustering procedures on 14 microsatellites (169 individuals) did not detect any geographically distinct cluster, and a high genetic admixture was recorded in all studied areas except for the individuals from the breeding sites in Norway, which were genetically very close. Estimation of migration rates through Bayesian inference confirms the scenario for the current mixing of goose populations. Subjects Biodiversity, Zoology Keywords mtDNA, Microsatellites, Greylag goose, Genetic structure, France and Norwa

Jasmonic Acid-Induced Changes in Brassica oleracea Affect Oviposition Preference of Two Specialist Herbivores

Jasmonic acid (JA) is a key hormone involved in plant defense responses. The effect of JA treatment of cabbage plants on their acceptability for oviposition by two species of cabbage white butterflies, Pieris rapae and P. brassicae, was investigated. Both butterfly species laid fewer eggs on leaves of JA-treated plants compared to control plants. We show that this is due to processes in the plant after JA treatment rather than an effect of JA itself. The oviposition preference for control plants is adaptive, as development time from larval hatch until pupation of P. rapae caterpillars was longer on JA-treated plants. Total glucosinolate content in leaf surface extracts was similar for control and treated plants; however, two of the five glucosinolates were present in lower amounts in leaf surface extracts of JA-treated plants. When the butterflies were offered a choice between the purified glucosinolate fraction isolated from leaf surface extracts of JA-treated plants and that from control plants, they did not discriminate. Changes in leaf surface glucosinolate profile, therefore, do not seem to explain the change in oviposition preference of the butterflies after JA treatment, suggesting that as yet unknown infochemicals are involved