Spectral sensitivity of the compound eyes of Anomala corpulenta motschulsky(Coleoptera:Scarabaeoidea)

The scarab beetle, Anomala corpulenta Motschulsky（Coleoptera： Scarabaeoidea）, is a widespread and destructive pest in China. Vision is one of the most important means of acquiring information about the external environment. In order to contribute to the understanding of the perception of visual stimuli in this species, the light sensitivity and spectral responses of the scarab beetle, A. corpulenta, were measured by using an electroretinogram（ERG） technique. In total, 14 monochromatic light intensities, between 340 and 605 nm, were applied to the compound eyes of A. corpulenta under varying levels of adaptation to dark and light conditions. The results showed that all light stimuli induced an ERG response, with varied amplitudes. The spectral sensitivity curve of dark-adapted eyes showed one major peak（~400 nm; near-ultraviolet）, a secondary peak（from 498 to 562 nm; yellow-green） and the third peakat 460 nm. By contrast, in light-adapted eyes, only a near-UV peak was observed. From these results, we conclude that the compound eye of A. corpulenta is likely to have at least three spectral types of photoreceptor. Significance of differences were also recorded in the responses of male and female compound eyes, as well as diurnally and nocturnally. The amplitude of ERG in response to white-light stimuli varied with the light intensity： The stronger the luminance, the higher the ERG value. This suggests that the compound eye of A. corpulenta adapts quickly to changing light conditions, enabling A. corpulenta to maintain nocturnal activities.

Kinetics study of ultrafast electron transfer from sensitized dyes to silver halide microcrystals

Spectral sensitization micromechanism of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr microcrystals with different dye concentrations is studied by using picosecond time-resolved fluorescence spectroscopy, and the dependences of electron transfer and spectral efficiency sensitization on different conditions are analysed in detail, With the steady spectroscopy, the wavelengths of absorption and fluorescence of J-aggregate adsorbed on AgBr microcrystals are found to shift to red relative to dye monomer. The spectrum of fluorescence has a red shift relative to the absorption peak. With the time-resolved fluorescence spectroscopy, the fluorescence decay curves of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr grains are found to be fitted well by a double-exponential decay function. The fitting curves consist of a fast and a slow component. Because of the large amplitude of the fast component, this fast decay should be attributable mainly to the electron transfer from J-aggregate of dye to a conduction band of AgBr.

Design of a Surface-Plasmon-Resonance Sensor Based on a Microstructured Optical Fiber with Annular-Shaped Holes

A novel design is proposed for highly sensitive surface-plasmon-resonance sensors. The sensor is based on a microstructured optical fiber with two layers of annular-shaped holes. A gold layer is deposited on the inner surface of the second hole-layer, in which the holes have several micrometers thickness in size, facilitating analyte infiltration and metal layer deposition. In the first layer of holes, the sector-ring^shaped arms, used as supporting strips, are utilized to tune the resonance depth of the sensor. Numerical results indicate that the sensor operation wavelength can be tuned across the C＋L-band. The spectral sensitivity of 1.0.104 nm. RIU-1 order of magnitude and a detection limit of 1.0.10-4 RIU order are demonstrated over a wide range of analyte refractive index from 1.320 to 1.335.

Classification of hyperspectral images based on a convolutional neural network and spectral sensitivity

In recent years,deep learning methods have gradually come to be used in hyperspectral imaging domains.Because of the peculiarity of hyperspectral imaging,a mass of information is contained in the spectral dimensions of hyperspectral images.Also,different ob jects on a land surface are sensitive to different ranges of wavelength.To achieve higher accuracy in classification,we propose a structure that combines spectral sensitivity with a convolutional neural network by adding spectral weights derived from predicted outcomes before the final classification layer.First,samples are divided into visible light and infrared,with a portion of the samples fed into networks during training.Then,two key parameters,unrecognized rate(δ)and wrongly recognized rate(γ),are calculated from the predicted outcome of the whole scene.Next,the spectral weight,derived from these two parameters,is calculated.Finally,the spectral weight is added and an improved structure is constructed.The improved structure not only combines the features in spatial and spectral dimensions,but also gives spectral sensitivity a primary status.Compared with inputs from the whole spectrum,the improved structure attains a nearly 2%higher prediction accuracy.When applied to public data sets,compared with the whole spectrum,on the average we achieve approximately 1%higher accuracy.

Spectral sensitivity of ALOS, ASTER, IKONOS, LANDSAT and SPOT satellite imagery intended for the detection of archaeological crop marks

This study compares the spectral sensitivity of remotely sensed satellite images,used for the detection of archaeological remains.This comparison was based on the relative spectral response(RSR)Filters of each sensor.Spectral signatures profiles were obtained using the GER-1500 field spectroradiometer under clear sky conditions for eight different targets.These field spectral signature curves were simulated to ALOS,ASTER,IKONOS,Landsat 7-ETM-,Landsat 4-TM,Landsat 5-TM and SPOT 5.Red and near infrared(NIR)bandwidth reflectance were re-calculated to each one of these sensors using appropriate RSR Filters.Moreover,the normalised difference vegetation index(NDVI)and simple ratio(SR)vegetation profiles were analysed in order to evaluate their sensitivity to sensors spectral filters.The results have shown that IKONOS RSR filters can better distinguish buried archaeological remains as a result of difference in healthy and stress vegetation(approximately 18%difference in reflectance of the red and NIR band and nearly 0.07 to the NDVI profile).In comparison,all the other sensors showed similar results and sensitivities.This difference of IKONOS sensor might be a result of its spectral characteristics(bandwidths and RSR filters)since they are different from the rest of sensors compared in this study.

Design of an Optical Water Pollution Sensor Using a Single-Layer Guided-Mode Resonance Filter

The optical characteristics of a simple, planar, single layer, dielectric Mg-based guided mode resonance filter （GMRF） were investigated by means of rigorous-coupled wave analysis （RCWA）. This filter has great potential for real-life applications, especially as bio- and environmental sensors. The structure of the proposed sensor is compact, and all of its layers can be grown in a single process. In this paper, we present results on the design of a water pollution sensor in the violet region of the visible spectrum. The spectral and angular sensitivities of the sensor for both the transverse electric （TE） and transverse magnetic （TM） polarization modes were estimated and compared for various regions in the violet spectrum. A spectral response characterized with a narrow bandwidth and low reflection side bands was realized by carrying out extensive parameter search and optimization. Optimal spectral and angular sensitivities were found for the sensor with a grating thickness of 100nm in the TM polarized mode where we found them to be 100nm and 40 degrees, per index refraction unit, respectively.

Synthesis and light absorption of benzotellurazole crown ether cyanine dye

Various methods for synthesis of 2-methyl-5,6-(1,4, 7,10,13-pentaoxatridecamethylene)benzotellurazole (8) are described. Under different conditions, alkylation of compound 8 with methyl iodide gave telluronium salt 1,2-dimethyl-5,6-(1,4,7,10,13-pentaoxatridecamethylene)benzotellurazolium iodide (15) or quaternary ammonium salt 2,3-dimethyl-5,6-(1,4,7,10,13-pentaoxatridecamethylene)benzotellurazolium iodide (14) in high yields, repectively. The cyanine dye 3,3'-dimethyl-5,6,5',6'-bis(1,4,7,10,13-pentaoxatridecamethylene)telluracarbocyanine iodide (16) is obtained by condensation of 14 with ethyl orthoformate in acetic anhydride, The visible absorption of the cyanine dye is also discussed.