Spectroscopy and Spectral Analysis 

About: Spectroscopy and Spectral Analysis is an academic journal. The journal publishes majorly in the area(s): Raman spectroscopy & Hyperspectral imaging. It has an ISSN identifier of 1000-0593. Over the lifetime, 5849 publications have been published receiving 16588 citations.

New index for crop canopy fresh biomass estimation

Abstract: The objective of the present study is to propose a new vegetation index for corn canopy fresh biomass estimation, which improves the ability to accurately estimate high biomass levels by remote sensing technology For this purpose, hyperspectral reflectance data of corn canopies were collected using a ground-based spectroradiometer during different field campaigns in a region of Quebec (Canada), from 2004 to 2008 Corresponding fresh biomass values were obtained by destructive measurements, and a hyperspectral image was also acquired using the Compact Airborne Spectrographic Imager (CASI) in 2005 A new biomass index named red-edge triangular vegetation index (RTVI) was designed and compared to existing indices used for fresh biomass estimation The results showed that RTVI was the best vegetation index for predicting canopy fresh biomass, with sustained sensitivity at high fresh biomass levels The best regression model between RTVI and canopy fresh biomass was the power fit, with determination coefficient (R2) of 096 With the validation by CASI imagery in 2005, good results were obtained The relationship between CASI predicted biomass and actual biomass was 058 (R2), with the RMSE of 044 kg x m(-2)

Discrimination of varieties of apple using near infrared spectra based on principal component analysis and artificial neural network model

Abstract: A new method for the discrimination of varieties of apple by means of near infrared spectroscopy (NIRS) was developed. First, principal component analysis (PCA) was used to compress thousands of spectral data into several variables and describe the body of spectra, the analysis suggested that the cumulate reliabilities of PC1 and PC2 (the first two principle components) were more than 98%, and the 2-dimentional plot was drawn with the scores of PC1 and PC2. It appeared to provide the best clustering of the varieties of apple. The loading plot was drawn with PC1 and PC2 through the whole wavelength region. The fingerprint spectra, which were sensitive to the variety of apple, were obtained from the loading plot. The fingerprint spectra were applied as ANN-BP inputs. Seventy five samples from three varieties were selected randomly, then they were used to build discrimination model. This model was used to predict the varieties of 15 unknown samples; the distinguishing rate of 100% was achieved. This model is reliable and practicable. So the present paper could offer a new approach to the fast discrimination of varieties of apple.

[Surface and interface analysis for copper phthalocyanine (CuPc) and indium-tin-oxide (ITO) using X-ray photoelectron spectroscopy (XPS)].

Abstract: Indium-tin-oxide (ITO) coated glass has been widely used as a hole injection electrode for organic light-emitting devices (OLEDs), but the work function of ITO film usually mismatches the highest occupied molecular orbital (HOMO) of the hole transport materials. Copper phthalocyanine (CuPc) has been used as a hole injection buffer to enhance the hole injection from ITO to the hole transport layer. A thin CuPc layer was thermally evaporated onto the ITO-coated glass substrate, and the surface and interface electron states of the CuPc/ITO close contact were measured and analyzed by X-ray photoelectron spectroscopy (XPS) technology. Results show that, in CuPc molecule, copper atom has a valence of +2 and interacts with nitrogen atoms through coordinate bonds. There are two kinds of carbon atoms: eight carbon atoms bonding with two nitrogen atoms and other 24 carbon atoms with an aromatic hydrocarbon character. The nitrogen atoms are also in two kinds of chemical environment: four nitrogen atoms only bond with two carbon atoms forming C-N=C bonds, and other four nitrogen atoms not only bond with carbon atoms but also bond with copper atom through coordinate bonds. Argon ion beam sputtering was used to study the interface characteristics of the CuPc/ITO contact. As sputtering time increases, the peaks of C 1s and N 1s spectra gradually become weaker, the peaks of Cu 2p, O 1s, In 3d and Sn 3d spectra get stronger. The core-levels of C 1s, N 1s, O 1s, In 3d and Sn 3d spectra all have chemical shifts towards higher or lower binding energy, but their behavior are different.

Investigation on photoconductive properties of MEH-PPV/CdSe-nanocrystal nanocomposites

Abstract: The photoconductive properties of photodiodes based on nanocomposites of water-soluble CdSe nanocrystals and poly[2-methoxy-5-(2-ethylhexyloxy-p-phenylenevinylen)] (MEH-PPV) were investigated. The photoluminescence intensity of the nanocomposites decreased with the increasing weight ratios of CdSe nanocrystals to MEH-PPV. By comparing the photocurrent action spectra of the nanocomposite device and the pristine MEH-PPV device, it was found that the nanocomposite device exhibited a wider photocurrent action range. In addition, the nanocomposite device displayed an obvious photovoltaic effect upon illumination. The process of exciton dissociation and charge transfer between the interface of CdSe nanocrystals and MEH-PPV was discussed.

[Ultraviolet absorption spectra of iodine, iodide ion and triiodide ion].

Abstract: Ultraviolet absorption spectra of iodine I2, iodide ion I(-) and triiodide ion I3(-) were studied, and molar absorptivities of these species were determined. Absorption spectrum of I2 aqueous solution appears as an absorption peak at 203 nm with a molar absorptivity of 1.96 x 10(4) L x mol(-1) x cm(-1). Absorption spectrum of I(-) appears as two absorption peaks at 193 and 226 nm with molar absorptivities of 1.42 x 10(4) and 1.34 x 10(4) L x mol(-1) x cm(-1), respectively. When I2 aqueous solution is mixed with KI solution, two absorption peaks appear at 288 and 350 nm, respectively, indicating the formation of I3(-). Using saturation method, molar absorptivities of I3(-) at 288 and 350 nm were determined to be 3.52 x 10(4) and 2.32 x 10(4) L x mol(-1) x cm(-1), respectively.