Estimation precision for a normalized response matrix in linear polarization calibration.

The purpose of polarization calibration is to obtain the response matrix of an instrument such that the subsequent observation data can be corrected. The calibration precision, however, is partially restricted by the noise of the detector. We investigate the precision of the normalized response matrix in the presence of signal-independent additive noise or signal-dependent Poisson shot noise. The influences of the source intensity, type of noise, and calibration configuration on the precision are analyzed. We compare the theoretical model and the experimental measurements of the polarization calibration to show that the relative difference between the two is less than 16%. From this result, we can use the model to determine the minimum source intensity and choose the optimal configurations that provide the required precision.

Optimal configurations for different incident polarization states in linear polarization calibration.

The purpose of polarization calibration is to measure the response matrix of an instrument and the deviation of noise to correct for subsequent flight measurements. The precision, however, is relative to the states of incident light. We investigate the influence of partially polarized light, in the presence of signal-independent additive noise or signal-dependent Poisson shot noise. We obtain the estimation precision for different numbers of the polarization state generators and analyzers in linear Stokes measurements. To reduce the influence of incident light, we suggest that the numbers of the polarization state generators and analyzers should be greater than or equal to 4. In particular, for an instrument including three polarizers oriented at 0°, 60°, and 120°, estimation precision is found to be dependent on the response matrix and incident polarization states.

Simultaneous detection of zearalenone, citrinin, and ochratoxin A in pepper by capillary zone electrophoresis.

In the present study, a simple and fast method for simultaneous detection of zearalenone, citrinin, and ochratoxin A utilising capillary zone electrophoresis with an ultraviolet detector was developed. The optimised approach was validated and applied using pepper samples. The proposed method yielded satisfactory linearity between the signal and the mycotoxin concentration in the range of 1.5-150 µg/kg for zearalenone, 4.5-150 µg/kg for citrinin, and 0.8-150 µg/kg for ochratoxin A. The limits of detection for these mycotoxins ranged from 0.3 to 1.5 µg/kg. The corresponding intra- and inter-day precisions were less than 3.5 % and 4.1 %, respectively. Moreover, the matrix effect was also assessed and the result was compared using the capillary zone electrophoresis and high-performance liquid chromatography methods. The developed approach could be used for simultaneous detection of zearalenone, citrinin, and ochratoxin A in pepper.

Design of a Compliant Mechanism Based Four-Stage Amplification Piezoelectric-Driven Asymmetric Microgripper.

The existing symmetrical microgrippers have larger output displacements compared with the asymmetrical counterparts. However, the two jaws of a symmetrical microgripper are less unlikely to offer the same forces on the two sides of a grasped micro-object due to the manufacture and assembly errors. Therefore, this paper proposes a new asymmetric microgripper to obtain stable output force of the gripper. Compared with symmetrical microgrippers, asymmetrical microgrippers usually have smaller output displacements. In order to increase the output displacement, a compliant mechanism with four stage amplification is employed to design the asymmetric microgripper. Consequently, the proposed asymmetrical microgripper possesses the advantages of both the stable output force of the gripper and large displacement amplification. To begin with, the mechanical model of the microgripper is established in this paper. The relationship between the driving force and the output displacement of the microgripper is then derived, followed by the static characteristics' analysis of the microgripper. Furthermore, finite element analysis (FEA) of the microgripper is also performed, and the mechanical structure of the microgripper is optimized based on the FEA simulations. Lastly, experimental tests are carried out, with a 5.28% difference from the FEA results and an 8.8% difference from the theoretical results. The results from theoretical calculation, FEA simulations, and experimental tests verify that the displacement amplification ratio and the maximum gripping displacement of the microgripper are up to 31.6 and 632 µm, respectively.

6-Bromo-1,3-benzothia-zol-2-amine.

The r.m.s. deviation from the mean plane for the non-H atoms in the title compound, C(7)H(5)BrN(2)S, is 0.011 Å. In the crystal, the mol-ecules are linked by N-H⋯N and N-H⋯Br hydrogen bonds to generate (010) sheets. Weak aromatic π-π stacking [centroid-to-centroid separation = 3.884 (10) Å] and possible C-H⋯Br inter-actions are also observed. The crystal studied was found to be an inversion twin.