LEAST-SQUARES POLYNOMIAL SMOOTHING FOR INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTRA

The use of least-squres polynomial smoothing in ICP-AES is discussed and a method of points insertion into spectral scanning intervals is proposed in the present paper. Optimal FWHM/SR ratio can be obtained, and distortion of smoothed spectra can be avoided by use of the recommended method.

EVALUATION OF THE EFFECT OF WAVELENGTH POSITIONING ERRORS ON KALMAN FILTERING RESULTS IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

This work evaluates the effect of wavelength positioning errors in spectral scans on analytical results when the Kalman filtering technique is used for the correction of line interferences in inductively coupled plasma atomic emission spectrometry (ICP-AES). The results show that a positioning accuracy of 0.1 pm is required in order to obtain accurate and precise estimates for analyte concentrations. The positioning error in sample scans is more crucial than that in model scans. The relative bias in measured analyte concentration originating from a positioning error in a sample scan increases linearly with an increase in the magnitude of the error and the peak distance of the overlapping lines, but is inversely proportional to the signal-to-background ratio. By the use of an optimization procedure for the positions of scans with the innovations number as the criterion, the wavelength positioning error can be reduced and, correspondingly, the accuracy and precision of analytical results improved.

IMPROVEMENT OF SELECTIVITY WITH NUMERICAL DERIVATIVE TECHNIQUES IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

One of the most attractive features of derivative spectrometry is its higher resolving power. In the present power, numerical derivative techniques are evaluated from the viewpoint of increase in selectivity, the latter being expressed in terms of the interferent equivalent concentration (IEC). Typical spectral interferences are covered, including flat background, sloped background, simple curved background and various types of line overlap with different overlapping degrees, which were defined as the ratio of the net interfering signal at the analysis wavelength to the peak signal of the interfering line. the IECs in the derivative spectra are decreased by one to two order of magnitudes compared to those in the original spectra, and in the most cases, assume values below the conventional detection limits. The overlapping degree is the dominant factor that determines whether an analysis line can be resolved from an interfering line with the derivative techniques. Generally, the second derivative technique is effective only for line overlap with an overlapping degree of less than 0.8. The effects of other factors such as line shape, data smoothing, step size and the intensity ratio of analyte to interferent on the performance of the derivative techniques are also discussed. All results are illustrated with practical examples.

MEASUREMENT AND CALCULATION OF SPONTANEOUS EMISSION BRANCHING RATIOS, RELATIVE OSCILLATOR-STRENGTHS, TRANSITION-PROBABILITIES AND LEVEL LIFETIMES FOR ATOMIC URANIUM

We propose a laser induced sensitized fluorescence spectrometry for measuring the spontaneous emission branching ratios o?the transitions from the ten levels 5f36d7s7p-7M7, 5f36d7s7p-7L6, 5f37s27p-5K6, 5f26d27s2 - 5L7, 5f46d7s - 7L6, (17,070cm-1)-5L6, 5f26d27s2-5K6, 6d7s7p-7L5, 5f36d7s7p-7K5 and 5f26d27s2-5I5 to the ground state of atomic uranium (UI) for the first time. Their relative oscillator strengths have been measured by means of hollow cathode discharge (HCD) emission spectrometry. The radiative...

Studies on hybridization effects of different geographic populations of Chlamys farreri - II. The medium-term growth and development of Chlamys farreri populations from China and Russia and their reciprocal crosses

Based on the research of juvenile (2, 3, 4 months) growth and survival of three populations of two different geographic areas in Chlamys farreri from Russian and China and their F, hybrids derived from Chinese cultural population (CC) female x Russian population (RW) male, Chinese wild population (CW) female x Russian population (RW) male, Russian population (RW) female x Chinese wild population (CW) the study of the medium-term (6, 8, 10, 12 months) growth and development of Chlamys farreri was carried out. The four determined results indicated that there existed different extent heterosis (3% similar to 52 %) for the growth in three types of F-1 hybrids, and the offspring derived from CC female X Rmale had a stronger heterosis among the crosses at the medium-term; the uptrend among traits are wet weight > shell width > shell length > shell height, Chinese cultural population could be recognized as excellent parent, and seasonal variations influence very much on the daily increment and growth rate of each trait of Chlamys farreri and it is only able to survive and could barely grow in winter (6 similar to 8 months), but grows fast in temperate season (10similar to12 months).

Chandrananimycins A-C: Production of novel anticancer antibiotics from a marine Actinomadura sp isolate M048 by variation of medium composition and growth conditions

In our screening of marine actinomycetes for bioactive principles, three novel antibiotics designated as chandrananimycin A (3c), B (3d) and C (4) were isolated from the culture broth of a marine Actinomadura sp. isolate M045. The structures of the new antibiotics were determined by detailed interpretation of mass, 1 D and 2 D NMR spectra.

Screening of salt tolerant watercress variants on natural seawater contained medium

The responses of stem segments of watercress (Nasturtium officinale R. Br.) to 6-BA,NAA and 2,4-D were studied. MS medium supplemented with 2.0 mg/L 6-BA, 0.2 mg/L 2,4-D was used for callus initiation and maintenance. MS medium supplemented with 4.0 mg/L 6-BA was suitable for plant regeneration and MS medium without plant hormone supplement was used for rooting and plant propagation. For screening of salt tolerant calli, stem segments of watercress were plated onto callus initiation medium containing 1/3 natural seawater. Seventeen out of the 325 plated explants produced calli. The growth curves demonstrated that the growth rate of salt-tolerant calli on saline medium almost matched that of the control calli on normal medium. Some of the salt-tolerant calli were transferred to the normal regeneration medium or saline regeneration medium to induce plant regeneration. In the first case, buds and shoots were regenerated in the same way as those of control calli on normal regeneration medium. More than 1 000 regenerated shoots were obtained of which 83 regenerated shoots were cut and transferred to saline MS base medium. At first, all shoot growth was inhibited, but 40 days after the transfer, rapid-growing axillary shoots were observed on 16 of the original shoots but none on the control shoots on saline MS base medium. Moreover, green spots appeared on most calli 10 days after they were transferred to saline medium, however buds appeared only on 5 calli from the 30 transferred calli and at the end only 2 rapid-growing shoots were obtained from two calli. In total, 18 variant lines were obtained through. propagation of the salt-tolerant shoots on saline MS base medium. RAPD analysis was performed in 10 of the 18 salt-tolerant variant lines and DNA variation was detected in all the tested variant lines.

Application of effective medium approximation theory to ocean remote sensing under wave breaking

Based on the effective medium approximation theory of composites, the empirical model proposed by Pandey and Kakar is remedied to investigate the microwave emissivity of sea surface under wave breaking driven by strong wind. In the improved model, the effects of seawater bubbles, droplets and difference in temperature of air and sea interface (DTAS) on the emissivity of sea surface covered by whitecaps are discussed. The model results indicate that the effective emissivity of sea surface increases with DTAS increasing, and the impacts of bubble structures and thickness of whitecaps layer on the emissivity are included in the model by introducing the effective dielectric constant of whitecaps layer. Moreover, a good agreement is obtained by comparing the model results with the Rose's experimental data.

Metabolic characteristics of sea cucumber Apostichopus japonicus (Selenka) during aestivation

Metabolic characteristics of the sea cucumber Aposticholpus japonicus (Selenka) during aestivation were studied in the laboratory. The effects of water temperature on oxygen consumption rate (OCR) and ammonia-N excretion rate (AER) in A. japonicus were determined by the Winkler and Hypobromite methods, respectively. Mature (large, 148.5 +/- 15.4 g, medium 69.3 +/- 6.9 g) and immature (small, 21.2 +/- 4.7 g) individuals aestivated at water temperatures of 20 and 25 degrees C, respectively. The metabolic characteristics of mature individuals were different from immature individuals during this period. The OCR of mature sea cucumbers peaked at 20 degrees C, and then dropped significantly at higher temperatures, whereas the OCR of the immature animals continued to increase slightly, even beyond the aestivation temperature. The AER of mature individuals peaked at 20 T, while that of the immature animals peaked at 25 degrees C. The relationships between dry weight (DW) and absolute oxygen consumption (R) and absolute ammonia-N excretion (N) could be described by the regression equation R or N=aW(b). With the exception of 15 degrees C, the O/N ratios (calculated in atomic equivalents) of large size sea cucumbers was close to 20 across the temperatures used in this study, indicating that their energy Source was a combination of lipid and protein. Oil the other hand, apart from small individuals maintained at 10 degrees C, the O/N ratios of the medium and small sea Cucumbers were close to 10, indicating that protein was their major energy source. The O/N ratios in all size groups remained unchanged after aestivation was initiated. (c) 2005 Elsevier B.V. All rights reserved.

Determination of trace arsenic and selenium in jellyfish by microwave digestion-hydride generation-atomic fluorescence spectrometry

A method of hydride generation-atomic fluorescence spectrometry was proposed in the present paper for the determination of trace arsenic and selenium in jellyfish. The samples were treated by the combination of microwave digestion and lyophilization. The optimal conditions for treating and analyzing samples were established. The problem of the effect of the superfluous acid in the digesting solution on the results was solved, and the influence of coexisting foreign ions on the determination of arsenic and selenium was investigated. The accuracy of the method was confirmed by the method of standard additions. This method proved to be simple, rapid and repeatable, and is suitable for the analysis of biologic samples containing water.

Synthesis of NiWO4 nano-particles in low-temperature molten salt medium

Nickel tungstate (NiWO4) nano-particles were successfully synthesized at low temperatures by a molten salt method, and characterized by Xray diffraction (XRD), transmission electron microscopy (TEM) and ultraviolet visible spectra techniques (UV-vis), respectively. The effects of calcining temperature and salt quantity on the crystallization and development of NiWO4 crystallites were studied. Experimental results showed that the well-crystallized NiWO4 nano-particles with about 30 nm in diameter could be prepared at 270 degrees C with 6:1 mass ratio of the salt to NiWO4 precursor. XRD analysis confirmed that the product was a pure monoclinic phase of NiWO4 with wolframite structure. UV-vis spectrum revealed that NiWO4 nano-particles had good light absorption properties in both ultraviolet and visible light region. (C) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Sensitisation identification of stainless steel to intergranular stress corrosion cracking by atomic force microscopy

A new technique was developed for characterisation of stainless steel to intergramilar stress corrosion cracking by atomic force microscopy. The technique proved to be effective in sensitisation identification of AISI 304 stainless steel and might be promising in sensitisation identification of other stainless steels. (c) 2007 Elsevier B.V. All rights reserved.

Some new triazole derivatives as inhibitors for mild steel corrosion in acidic medium

Two triazole derivatives, 3,4-dichloro-acetophenone-O-1'-(1',3',4'-triazolyl)-methaneoxime (4-DTM) and 2,5-dichloro-acetophenone-O-1'-(1',3',4'-triazolyl)-methaneoxime (5-DTM) were synthesized, and the inhibition effects for mild steel in 1 M HCl solutions were investigated by weight loss measurements, electrochemical tests and scanning electronic microscopy (SEM). The weight loss measurements showed that these compounds have excellent inhibiting effect at a concentration of 1.0 x 10(-3) M. The potentiodynamic polarization experiment revealed that the triazole derivatives are inhibitors of mixed-type and electrochemical impedance spectroscopy (EIS) confirmed that changes in the impedance parameters (R-ct and C-dl) are due to surface adsorption. The inhibition efficiencies obtained from weight loss measurements and electrochemical tests were in good agreement. Adsorption followed the Langmuir isotherm with negative values of the free energy of adsorption Delta G(ads)(o). The thermodynamic parameters of adsorption were determined and are discussed. Results show that both 4-DTM and 5-DTM are good inhibitors for mild steel in acid media.

内陆湖沼相和近海沼泽相沉积环境煤中微量元素和矿物的对比研究—以辽宁北票、江西建新和桥头煤研究为例

Using knowledge of geology, geochemistry, coal petrology, mineralogy, by means of a variety of advanced measuring methods such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled atomic emission spectrometry (ICP-AES), X-ray powder diffraction (XRD), scanning electron microscopy with energy-dispersive spectrometer(SEM-EDS), sequential chemical extract and density fractions, the characteristics of trace elements and minerals in Jurassic Beipiao coal mine under inland limnetic sedimentary environment and in late Permian Jianxin and Qiaotou coal mines under paralic swamp sedimentary environment were studied. Compared with the average concentration in the world bituminous coals, the Beipiao coal was characterized by relatively high contents of Sc, Ti, Cr, Co, Ni, Zn, Se, Sr, Zr, Y, Ba, REE and Th, and lower contents of V, Rb, Cd, Sn, Pb, Bi and U; while the Jianxin coal was relatively enriched in Li, Sc, Ga, Sr, Y, Nb, Sb, Th and U, with low concentration of Be, Co, Ni, Cu, Ge, Zr, Mo, Cd, Cs, Ba, Pb and Bi; and the Qiaotou coal was enriched in Li, Sc, Sr, Nb, Ta, Zr, REE, Hf, Th and U, with low concentration of Be, V, Co, Ni, Cu, Ge, Mo, Cd, Cs, Ba, Tl, Pb and Bi. The concentrations of Ca, Mg and K in Beipiao coal are higher than those in Jianxin coal and Qiaotou coal, while Fe, S and Ti in Beipiao coal are lower than those in Jianxin coal and Qiaotou coal. The proximate analysis of coal samples was carried out, which indicated that Beipiao coal was medium- to high- ash (5.92-60.68%) with low sulphur coal, and Jianxin coal and Qiaotou coal was medium to high ash (8.85-46.33%) with high sulphur. The reflectivity was measured, which explained that Beipiao coal belonged to high volatile bituminous coal, Jianxin coal was low volatile bituminous coal and Qiaotou coal was low volatile anthracite. Quantitative maceral analyses were studied. The characteristics of rare earth elements (REE) were investigated, which showed that the total contents of REE were higher than that of the world's average content. With the increase of coal's metamorphic grade, the total contents of REE decreased from 98.5 X 10"6 of Beipiao coal to 94.2 X 10"6 of Jianxin coal, and to 75.9 X 10"6 of Qiaotou coal, and 5Eu reduced which indicated that the element Eu depleted. The characteristics of REE was controlled by the metamorphic grade of coal. And REE were mainly absorbed in clay minerals in Beipiao coal samples, while in Jianxin and Qiaotou coal mines, REE were primarily related to clay mineral and pyrite. The variation of trace elements in vertical direction of coal seams was studied, and the results showed that different trace elements differed greatly. The correlation between trace elements and ash were determined. Four major trace elements (aluminium-silicates, sulphide, carbonate and phosphate) accounted for the occurrence and distribution of most elements studied were determined. Coal samples were separated by density fraction, which showed that Cr, Cu, Mo and Pb were closely related to inorganic matters mainly distributed in P >2.6 and dropped remarkably in the density fractions P <2.3 . The occurrences of Co, Cr, Ni, As, Se, Mo, U were studied directly and quantitatively using sequential chemical extract with six steps, which showed that Co. Ni, Mo and U were mainly in the form of mineral, and As, Se chiefly in the form of organic state, while Cr mostly in the form of organic state and mineral. Major mineral phases presented in the Beipiao coal were Kaolinite, illite, quartz, calcite, and small amount of siderite, barite. While major mineral phases in Jianxin and Qiaotou coal were pyrite, kaolinite, and small amount of marcasite, rutile, sphalerite. This is the first time that the chromite in the coal was discovered in China, which indicates that Cr occurrence appeared in the form of chromite. The ratio of Sr/Ba, Sr/Ca and V/Ni in Beipiao coal mine under inland limnetic is smaller than that of in Jianxin and Qiaotou coal mines under paralic swamp. The ratio of K/Na and Th/U of Beipiao coal mine is higher than that of Jianxin and Qiaotou coal mine, which proved that Beipiao coal was not affected by sea water and Jianxin and Qiaotou coal were affected by sea water. Trace elements such as Cr, Ni, Mo in minerals were analyzed by SEM-EDS. The factors controlling the enrichment of trace elements can be divided into syngenetic stage factors and epigenetic stage factors.