The theory and mechanical realization of an ideal scanning methodfor a single-channel imaging microwave radiometer

The scan path of an imaging microwave radiometer is determined so that the desired area is totally covered, while the overlap between successive sweeps is minimized. This minimizes the number of redundant data points, which, in turn, leads to faster and more economical postprocessing. Different scanning methods and sampling techniques are discussed in brief. Conical scan is chosen and three different approaches are presented. A theory that relates the flight velocity to the angular velocity of the antenna beam to provide an ideal scan pattern is formulated for pendulum scan. Results of each scan method are presented and compared, and the best one is chosen. Some considerations about the mechanical realization and an outline of the instrument are presented     

Intraphase Microstructure–Understanding the Impact on Organic Solar Cell Performance

A comprehensive study of the effect of intraphase microstructure on organic photovoltaic (OPV) device performance is undertaken. Utilizing a bilayer device architecture, a small molecule donor (TIPS‐DBC) is deposited by both spin‐coating and by thermal evaporation in vacuum. The devices are then completed by thermal evaporation of C₆₀, an exciton blocking layer and the cathode. This bilayer approach enables a direct comparison of device performance for donor layers in which the same material exhibits subtle differences in microstructure. The electrical performance is shown to differ considerably for the two devices. The bulk and interfacial properties of the donor layers are compared by examination with photoelectron spectroscopy in air (PESA), optical absorption spectroscopy, charge extraction of photo‐generated charge carriers by linearly increasing voltage (photo‐CELIV), time‐resolved photoluminescence measurements, X‐ray reflectometry (XR), and analysis of dark current behavior. The observed differences in device performance are shown to be influenced by changes to energy levels and charge transport properties resulting from differences in the microstructure of the donor layers. Importantly, this work demonstrates that in addition to the donor/acceptor microstructure, the intraphase microstructure can influence critical parameters and can therefore have a significant impact on OPV performance.     

Airborne imaging radiometer scan simulation

An imaging radiometer scan simulation program is developed for comparing the performance of different scan patterns and process behavior under varying circumstances. The program gives the radiometer's antenna beam the desired scan motion over an artificial target scene, computes the antenna radiometric temperature as the convolution of the antenna pattern with the scene brightness temperature deviation, computes a moving average of the antenna output, and records the data values as well as the corresponding coordinates at the sampling moments. The simulation indicated that a helicopter-borne imager needs at least passive attitude stabilization. In addition, the state-of-the-art sampling rate was found to be too slow, if the sampling period is set equal to the integration time. A detailed study revealed the achievable spatial resolution (line pairs/length unit-definition) to be 1.0-1.2×footprint dimensions, but the integration and sampling periods should be as short as 0.2-0.4×footprint dimensions     

Determination of positional distribution of butyryl groups in milkfat triacylglycerols,triacylglycerol mixtures,and isolated positional isomers of triacylglycerols by gas chromatography and1H nuclear magnetic resonance spectroscopy

Positional isomers (1-butyryl-2X-3Y-rac-glycerol and 2-butyryl-1X-3Y-rac-glycerol;X,Y=long-chain acyls) of saturated triacylglycerols (TAG) with 34 and 40 acyl carbons were shown to separate in two chromatographic peaks on immobilized phenyl(65%) methylsilicone column by gas-liquid chromatography, and on reversed-phase ODS-1 column by high-performance liquid chromatography. The analysis of 500-MHz¹H nuclear magnetic resonance (NMR) spectra showed distinct differences between 2-butyryl-1X-3Y-rac-glycerol and 1-butyryl-2X-3Y-rac-glycerol isomers in the resonance signals of methylene and methine protons of glycerol backbone, and carbon-2 methylene of acyl groups, and methyl protons of butyryl group. The¹H NMR spectra of three interesterified mixtures of three monoacid TAG containing saturated butyrate and caproate TAG and unsaturated butyrate TAG showed that triplets of methyl protons of butyryl groups atsn-1(3)- andsn-2-positions in saturated and unsaturated TAG had similar chemical shifts and that the chemical shift of caproyl methyl protons was different from those of butyryl methyl protons. The positional distribution of butyryl groups in isolated positional isomers of butyrate TAG, interesterified TAG mixtures, and natural and interesterified butteroil can be determined by integration of these signals.     

Fractionation of the triacylglycerols of lipase-modified butter oil

Triacylglycerols (TGs) of lipase-modified butter oil were separated into saturated, monoene, diene and triene fractions on ap-propylbenzene sulfonic acid solid-phase extraction column loaded with silver ions. Fatty acid analysis of the fractions showed that the amounts of saturated TGs (98.4 mol%) and monoene TGs (26.0 mol%) in the saturated and monoene fractions, respectively, were close to the theoretical amounts of TGs in pure fractions. The column method provides a useful alternative to AgNO₃-thin-layer chromatography as a means of separating the TGs of butterfat and producing relatively pure TG fractions for further analysis by gas chromatography (GC) or GC-mass spectrometry.     

Covalently Mercurated Molecular Beacon for Discriminating the Canonical Nucleobases

A highly nucleobase-discriminating metalated nucleoside analogue, 3-fluoro-2-mercuri-6-methylaniline, was incorporated into an oligonucleotide molecular beacon. Fluorescence emission spectra were measured after the addition of four different complementary strands, in which the nucleobase opposite the metalated analogue varies. The fluorescence results showed a clear binding selectivity at room temperature, in the order G>T>C>A. The selectivity is based on the different affinities between the metalated nucleoside analogue and the canonical nucleobases. The synthesized probe is capable of robust discrimination between the two purine as well as the two pyrimidine bases by fluorescence at room temperature, and more sophisticated temperature analysis allows clear separation of every canonical nucleobase. The probe would, hence, be a suitable method for the detection of single nucleotide polymorphisms.     

Regiospecific determination of short-chain triacylglycerols in butterfat by normal-phase HPLC with on-line electrospray-tandem mass spectrometry

This study uses normal-phase HPLC with on-line positive ion electrospray mass spectrometry (ESI-MS) to obtain quantitative compositional data on both synthetic and butterfat short-chain TAG. The product ion tandem MS of standards averaged 11.1 times lower in abundance of the ion formed by cleavage of FA from the sn-2-position for the pairs of regioisomers in the TAG classes: L/L/S-L/S/L and L/S/S-S/L/S, where L denotes long and S short acyl chain (C₂−C₆). The molar correction factors, determined for 42 regioisomeric pairs of short-chain TAG of 20 randomized mixture of standards, differed by 1.4–80% as the ratios varied between 0.217 and 5.847. Butterfat TAG were resolved into four fractions on short flash chromatography grade silica gel columns. Pairs of regioisomers in the TAG classes L/S/S-S/L/S with predominance of L/S/S isomers and the sole regioisomers in the TAG classes L/L(M)/S were identified by tandem MS, where M denotes either 8∶0 or 10∶0 acyl chain. The total proportion of L/L(M)/S isomers was estimated at 34.7 and that of L/S/S-S/L/S at 1.0 mol%, including a small proportion of S/S/S. In contrast to previous work, the present data indicate the presence of a small proportion of butyric and caproic acids in the sn-1-position. The overall distribution of the FA in the short-chain TAG of butterfat, calculated from direct MS measurements, was consistent with the results of indirect determinations based on stereospecific analyses of total butterfat.     

New Evaluation of $$T-T_{2000}$$ from 0.02 K to 1 K by Independent Thermodynamic Methods

This paper reports on the results achieved within the European Metrology Research Programme project “Implementing the new kelvin—InK” in the low-temperature range below 1 K. One of the main objectives of the InK project was the determination of new thermodynamic temperature data for comparison with the Provisional Low Temperature Scale 2000 (PLTS-2000), to provide reliable \(T-T_{2000}\) values. To this end, we have investigated three different types of primary thermometers: the current sensing noise thermometer, the primary magnetic field fluctuation thermometer and the Coulomb blockade thermometer. Based on a thorough investigation of the thermometers, detailed uncertainty budgets were established for the measurement of thermodynamic temperatures. Direct comparison measurements between all thermometers demonstrate the agreement of temperature measurements within less than 1 %. Our new \(T-T_{2000}\) data confirm the correctness of the PLTS-2000 in the temperature range from 20 mK up to about 700 mK with relative combined standard uncertainties better than 0.62 %.     

Mass spectrometric identification of triacylglycerols of enzymatically modified butterfat separated on a polarizable phenylmethylsilicone column

Original butter oil, butter oil interesterified withPseudomonas fluorescens lipase as catalyst, and the saturated, monoene, diene and triene fractions of interesterified butter oil from silver ion chromatography on ap-propylbenzene sulfonic acid column were analyzed on a polarizable phenyl(65%)methylsilicone column. Major and also some minor molecular species of triacylglycerols (TG) were identified from the electron-impact (EI) gas chromatography/mass spectrometry analytical data for the original and lipase-modified butter oil and the four fractions. Acyl + 74 and acyl + 128 fragments of EI mass spectral data proved useful, in addition to acyl and M - RCOO fragments, in the identification of molecular species of TG. The TG compositions of the modified butter oils were compared with the composition calculated according to random distribution and with the TG composition of original butter oil.