A program for atomic wavefunction computations by the parametric potential method

Title of program: MAPPAC Catalogue number: AAKC Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland (see application form in this issue) Computer for which the program is designed and others upon which it is operableComputer: UNIVAC 1108; Installation: Orsay, France; C.D.C. 6600. Jerusalem, Israel. Programming language used: FORTRAN IV High speed storage required: 50 000 words of 36 bits Is the program overlaid? No Number of magnetic tapes: None What other peripherals are used?: Card Reader; Printer; Punch. Number of cards in combined program and test deck: 3600 Card punching code: IBM BCD 026     

A Study of Complexation-ability of Neutral Schiff Bases to Some Metal Cations

The constants of the extraction equilibrium and the distribution for dichloromethane as an organic solvent having low dielectric constant of metal cations with chiral Schiff bases, benzaldehydene-(S)-2-amino-3-phenylpropanol (I), ohydroxybenzaldehydene-( S)-2-amino-3-phenyl-propanol (II), benzaldehydene-(S)-2- amino-3-methylbutanol (III) with anionic dyes [4-(2-pyridylazo)-resorcinol mono sodium monohydrate (NaPar), sodium picrat (NaPic) and potassium picrat (KPic)] and some heavy metal chlorides were determined at 25 ºC. All the ligands have given strongest complexation for NaPar. In contrast, similar behaviour for both alkali metal picrates is not apparent in the complexation of corresponding ligands.     

On the origin of fatigue corrosion cracking in Al7075

The fatigue corrosion cracking of the Al7075 alloy has been investigated by Scanning Electron Microscopy (SEM) and Auger Electron Spectroscopy (AES). Specimen exposed to cyclic load at room temperature until crack initiation show a significant increase of magnesium within a distance of about 1 μm around the crack, while almost no aluminum was left. This segregation effect has been investigated in detail, yielding that the diffusion should most likely be driven by the gradient of the chemical potential through the oxidation of magnesium at the surface, while the required mobility for the diffusion process was gained by the mechanical stress of the cyclic loading.     

Accurate band gap determination of chemically synthesized cobalt ferrite nanoparticles using diffuse reflectance spectroscopy

Optical band gap of cuboidal Cobalt ferrite (CoF) Nanoparticles (NP), synthesized using wet chemical method, was accurately determined, by combining Diffuse Reflectance Spectroscopy (DRS) of the nanopowder, Schuster-Kubelka-Munk (SKM) formalism and the application of a detailed band gap estimation algorithm, using which absorption onsets and corresponding base line segments from the Tauc plots were precisely identified. Structural and compositional characterizations such as XRD, FE-SEM, TEM and EDX, were used to conclude that the NP exhibited cubic crystal structure with an average crystallite size of 14 nm. The values of indirect and direct band gaps were calculated to be 0.79 ± 0.01 eV and 1.5 ± 0.01 eV, respectively. The band gap shift for the nanocrystallites, from the bulk band gap, estimated using the effective mass model, came up to a value of 0.084 eV, which corresponded well to the experimentally obtained direct band gap of CoF NP. The direct and indirect band gap values were found to be well consistent with the partially inverse spinel crystal structure of the NP, emphasized using magnetization measurement.     

Alternative approach for defining the particle population requirements for static image analysis based particle characterization methods

For image based particle characterisation approaches one of the most common discussion points is determining the number of particles required to have statistical confidence that the measurement is able to adequately describe the distribution of the sample. This topic becomes significantly more challenging when applied to the extraction of single component size distributions from multi-component samples.The aim of this work was to propose a means to accurately assess the particle number requirements using a method specific approach. The method applies a sub-sampling method to the original imaged dataset in order to provide an understanding of the impact of sub-sampling on the ability to accurately reproduce the original distribution.The method was applied to understand the particle number requirements for two batches of theophylline anhydrous with varied particle size distributions, using the input size distribution to guide the requirements for the subsequent multi-component samples of both materials.The results demonstrate the utility of the method to determine the appropriate number of particles required to recreate the size distributions. Whilst the minimum number of particles required to be sampled can be estimated, how those particles are sampled can also affect the validity of the measurement and must be taken into consideration.     

基于C Sharp的锂电池阻抗谱测量系统设计

本文介绍了基于C Sharp的锂电池阻抗谱测量系统设计,该系统主要由PC机、ARM、直接数字频率合成器（DDS）、AD5933、信号调理电路等模块构成。该系统经过校准后,通过对两种阻抗模型的测量和分析,其结果表明该系统的测量精度在3．5％以内。最后,测得了HL－18650M锂电池在充满电时10mHz至100KHz频带的阻抗谱。较之传统分立方式的锂电池电化学阻抗谱测量系统,该系统具有体积小、集成度高、成本低、精度较高的突出优点,有利于锂电池阻抗谱测量系统的大规模生产与应用。     

Spectroscopic determination of leaf water content using continuous wavelet analysis

The gravimetric water content (GWC, %), a commonly used measure of leaf water content, describes the ratio of water to dry matter for each individual leaf. To date, the relationship between spectral reflectance and GWC in leaves is poorly understood due to the confounding effects of unpredictably varying water and dry matter ratios on spectral response. Few studies have attempted to estimate GWC from leaf reflectance spectra, particularly for a variety of species. This paper investigates the spectroscopic estimation of leaf GWC using continuous wavelet analysis applied to the reflectance spectra (350-2500 nm) of 265 leaf samples from 47 species observed in tropical forests of Panama. A continuous wavelet transform was performed on each of the reflectance spectra to generate a wavelet power scalogram compiled as a function of wavelength and scale. Linear relationships were built between wavelet power and GWC expressed as a function of dry mass (LWC_D) and fresh mass (LWC_F) in order to identify wavelet features (coefficients) that are most sensitive to changes in GWC. The derived wavelet features were then compared to three established spectral indices used to estimate GWC across a wide range of species.Eight wavelet features observed between 1300 and 2500 nm provided strong correlations with LWC_D, though correlations between spectral indices and leaf GWC were poor. In particular, two features captured amplitude variations in the broad shape of the reflectance spectra and three features captured variations in the shape and depth of dry matter (e.g., protein, lignin, cellulose) absorptions centered near 1730 and 2100 nm. The eight wavelet features used to predict LWC_D and LWC_F were not significantly different; however, predictive models used to determine LWC_D and LWC_F differed. The most accurate estimates of LWC_D and LWC_F obtained from a single wavelet feature showed root mean square errors (RMSEs) of 28.34% (R² = 0.62) and 4.86% (R² = 0.69), respectively. Models using a combination of features resulted in a noticeable improvement predicting LWC_D and LWC_F with RMSEs of 26.04% (R² = 0.71) and 4.34% (R² = 0.75), respectively. These results provide new insights into the role of dry matter absorption features in the shortwave infrared (SWIR) spectral region for the accurate spectral estimation of LWC_D and LWC_F. This emerging spectral analytical approach can be applied to other complex datasets including a broad range of species, and may be adapted to estimate basic leaf biochemical elements such as nitrogen, chlorophyll, cellulose, and lignin.     

Deep UV based DOAS system for the monitoring of nitric oxide using ratiometric separation techniques

The investigation of an ultra violet DOAS (differential optical absorption spectroscopy) sensor based on fibre-optic technology for the monitoring of nitric oxide gas in an exhaust environment is described. Cross-sensitivity issues with other gases present in the environment were realised and ratiometric separation techniques were developed in order to reduce the sensor's susceptibility to these interferences. Experimental results describing the calibration of the sensor against a commercial analyser and tests documenting the sensor's operating capabilities within the exhaust of an engine are presented. The lower limit of detection for the sensor was found to be 5 ppm with response times of 3.4 s.     

A localized surface plasmon resonance nanosensor based on rhombic Ag nanoparticle array

A localized surface plasmon resonance (LSPR) nanosensor by using a rhombic Ag nanoparticle array is proposed and developed. The LSPR extinction spectra of the antigen or antibody with lower concentration are detected. The obtained results detected from 100 nM target molecule indicate a larger wavelength shift for the rhombic based nanosensor than the triangular based nanosensor. By experimental detection, we demonstrated that the refractive index sensitivity is 266.2 nm per refractive index unit for Ag rhombic nanoparticle with in-plane width of 140 nm and out-of-plane height of 47 nm.     

Possible interference in the sequential voltammetric determination at trace and ultratrace concentration level of platinum group metals (PGMs) and lead : Application to environmental matrices

The present work describes a procedure for the sequential determination of Pd(II), Pt(II), Rh(III), by square wave adsorption stripping voltammetry (SWAdSV) and Pb(II) by square wave anodic stripping voltammetry (SWASV) in environmental matrices (sediments, soils and superficial water) in the presence of possible metal interferences, including high concentration ratios.The supporting electrolytes were 0.1 mol/L HCl, 0.1 mol/L HCl + 1.8 × 10⁻⁴ mol/L dimethylglyoxime (DMG) and 0.6 mmol/L formaldehyde + 1.2 mmol/L hydrazine (formazone complex) in 0.1 mol/L HCl.The voltammetric measurements were carried out using, as working electrode, a stationary hanging mercury drop electrode (HMDE), a platinum wire as auxiliary and an Ag|AgCl|KCl_sat as reference electrode.The analytical procedure was verified by the analysis of standard reference materials (CCRMP-CANMET-TDB-1 and CCRMP-CANMET-UMT-1 (rock soils), Sea Water BCR-CRM 403 and Fresh Water NIST-SRM 1643d). In the case of water standard reference materials, the solutions were spiked with known element concentrations, successively verifying the percentage recovery.In the presence of reciprocal interference, the standard addition method considerably improved the resolution of the voltammetric technique, even in the case of very high element concentration ratios.Once set up on the standard reference materials, the analytical procedure was transferred and applied to sediments, soils and superficial waters sampled in proximity of superhighway and in the Po River mouth area.A critical comparison with spectroscopic measurements is also discussed.