ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (12)
  • Articles: DFG German National Licenses  (12)
  • 1995-1999  (12)
  • 1997  (8)
  • 1996  (4)
Collection
  • Articles  (12)
Source
Keywords
Publisher
Years
  • 1995-1999  (12)
Year
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Differential cross sections for state specific reactive scattering of Na–SF6→NaF–SF5 (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 3620-3628 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Double-differential cross sections for the interaction of Na(3 2S) and Na(3 2P) with SF6 have been measured in crossed beam experiments for center of mass collision energies between 0.25 and 1.75 eV. In comparison with recently reported experiments the reaction with vibrationally excited SF6 is found to be more effective than the one with electronically excited Na. Results from an ab initio CASSCF calculation with Na in the ground state and the 3P state are presented. The experimental findings and the results from the calculation lead us to two different models for the reaction in the ground state and the excited state: While the well known harpooning model is verified for the ground state the reactive collisions with excited Na are mediated by nonadiabatic (nonreactive) transitions to the ground state surface. For these transitions the vibrational motion of SF6 is much more efficient than the relative motion in the collision. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471064
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    CW laser performance of Yb and Er,Yb doped tungstates (1997)
    Springer
    Applied physics 64 (1997), S. 409-413 
    Details
    ISSN: 1432-0649
    Keywords: PACS: 42.55 R; 42.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract.  Room temperature cw laser action of Yb3+-doped KY(WO4)2 and KGd(WO4)2 crystals at 1.025 μm and Er, Yb : KY(WO4)2 at 1.54 μm has been demonstrated under pumping by both Ti-sapphire laser and InGaAs laser diodes. A slope efficiency of Yb-lasers up to 78% has been obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003400050191
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    An advanced unified power flow controller (1996)
    Springer
    Electrical engineering 79 (1996), S. 303-310 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Contents This paper describes the implementation of a new control approach for the Unified Poer Flow Controller (UPFC), which provides active filtering capabilities to this equipment, besides the functions of power flow control and voltage control, as originally proposed by L. Gyugyi [1,2]. The power circuit is made up from two PWM converters which share a common dc link without the need of dc power supplies. An integrated controller attends to both series and shunt converters of the UPFC. It is based on the theory of instantaneous active and reactive power defined in the α-β-0 reference frame [3,4]. A complete model of the new UPFC has been implemented in a digital simulator. Simulation results have confirmed that the new approach has higher performance than those UPFCs which use traditional definitions of powers in the controller.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01245883
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Cr(III)/Cr(VI) speciation in aerosol particles by extractive separation and thermal ionization isotope dilution mass spectrometry (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 1050-1055 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  An isotope dilution mass spectrometric (IDMS) method, using the formation of positive thermal ions, was developed for Cr(III) and Cr(VI) speciation in aerosol particles. Cr(III) and Cr(VI) spike species, enriched in 53Cr, were applied for the isotope dilution step. After leaching of filter collected aerosol samples by an alkaline solution at pH 13, species separation was carried out by extraction with a liquid anion exchanger in methyl isobutyl ketone. Cr(VI) in the organic phase was re-extracted into an ammoniacal solution and chromium was then isolated from both fractions of species by electrodeposition. Detection limits of 30 pg/m3 for Cr(III) and of 8 pg/m3 for Cr(VI) were achieved in atmospheric aerosols for volumes of air samples of about 120 m3. These low detection limits allowed the determination of chromium species in continental aerosol particles in dependence on different seasons. The Cr(III) /Cr(VI) ratio was always found to be about 0.3 whereas dust from soil erosion, which is probably the primary source of chromium in the atmosphere, showed higher ratios. This indicates that chromium is oxidized in the atmosphere. The accuracy of the method was demonstrated in two interlaboratory comparisons of Cr(VI) determinations in welding dust samples. The IDMS method also contributed to the certification of a corresponding standard reference material organized by the Standard Reference Bureau of the European Union. Chromium speciation, including the determination of elemental chromium Cr(0), was carried out in aerosols of different welding processes for stainless steel. These analyses showed distinct differences in the distribution of chromium species in the welding process and can be used as an exact calibration method for routine methods in this important field of monitoring corresponding working places.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    To Professor Dr. Karlheinz Ballschmiter on his 60th birthday (1997)
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 207-207 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050561
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Determination of halogen species of humic substances using HPLC/ICP-MS coupling (1997)
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 430-433 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A mass spectrometric method for the determination of chlorine, bromine and iodine species of humic substances (HS) has been developed by coupling a HPLC system with ICP-MS. Using size exclusion chromatography, the method was applied to the characterization of natural water samples (ground water, seepage water from soil, brown water) and a sewage water sample. Quantification of iodine/HS species was carried out by the on-line isotope dilution technique, which was not possible for bromine and chlorine species because of mass spectroscopic interferences by using a quadrupole ICP-MS. Characteristic fingerprints of the halogen/HS species, correlated with the corresponding UV chromatogram, were obtained dependent on the different origin of HS. Biological influences were indicated when following changes of the iodine/HS species composition by aging. The formation of iodine/HS species from inorganic iodide was investigated by labelling experiments with an 129I– spike solution, resulting in the finding that specific HS fractions are preferably iodinated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Identification of ground water contaminations by landfills using precise boron isotope ratio measurements with negative thermal ionization mass spectrometry (1997)
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 375-377 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  Precise boron isotope ratio measurements with negative thermal ionization mass spectrometry were used for the identification of ground water contaminations by leakages of landfills. BO- 2thermal ions were produced to determine the 11B/10B isotope ratio, which was expressed as δ11B value in ‰ normalized to the standard reference material NIST SRM 951. For example, household waste influences the boron isotope ratio by specific components such as washing powder. In the case of one investigated landfill low δ11B values correlate well with high boron concentrations in contaminated seepage water samples and vice versa for uncontaminated ground water samples. Possible boron contributions of rainwater were taken into account, determining a boron content of 2.3 μg/L and a δ11B value of 13.1‰ for a representative sample. Such low boron concentrations were determined by isotope dilution mass spectrometry (detection limit 0.3 μg/L) whereas higher contents were also analyzed by a spectrophotometric method. However, different sources of contamination could only be identified by the isotope ratio and not by the concentration of boron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050590
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Determination of heavy metal complexes with humic substances by HPLC/ICP-MS coupling using on-line isotope dilution technique (1997)
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 438-441 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An isotope dilution mass spectrometric (IDMS) method has been developed for the simultaneous determination of the complexes of 11 heavy metals (Ag, Cd, Cu, Mo, Ni, Pb, Tl, U, W, Zn and Zr) with humic substances (HS) by coupling HPLC with ICP-MS and applying the on-line isotope dilution technique. The HPLC separation was carried out with size exclusion chromatography. This HPLC/ICP-IDMS method was applied to samples from a brown water, ground water, sewage and seepage water as well as for a sample containing isolated fulvic acids. The total contents of heavy metals and of their complexes were analyzed in these samples with detection limits in the range of 5–110 ng/L. The analysis of heavy metal/HS complexes from the different waters resulted in characteristic fingerprints of the distribution pattern of heavy metals in the separated HS fractions. A comparison between the total heavy metal concentrations and their portions bound to humic substances showed distinct differences for the various metals. Simultaneous 12C detection was used for the characterization of HS complexes not identified by UV detection and for the determination of relative DOC concentrations of chromatographic peaks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050606
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Biogenic volatile organoiodine and organobromine hydrocarbons in the Atlantic Ocean from 42°N to 72°S (1997)
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 298-305 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  During the cruise ANT X/1 and 2 of the research vessel Polarstern from November 1991 to March 1992, 39 surface water samples of the Atlantic Ocean from 42°N to 72.5°S were collected and analysed for their concentration of volatile iodinated and brominated hydrocarbons. The concentration of chlorophyll-a was used as an indicator for phytoplankton, which is one of the main producers of iodinated and brominated compounds in the ocean. For determination of chlorophyll-a, fluorescence spectroscopy was applied, whereas the measurement of halogenated volatile hydrocarbons was carried out by a purge and trap system with subsequent gas chromatographic separation and detection by an electron capture detector. With this technique the brominated substances CHBr3, CH2Br2, CHBr2Cl and CHBrCl2 have been detected in the range of 〈0.03 ng/L to 15 ng/L. For these volatile bromomethanes a distinct concentration profile was found. CHBr3 was always found to be the substance with the highest concentration followed by CH2Br2, CHBr2Cl and CHBrCl2. It could also be shown that in addition to CH3I, which for a long time was believed to be the only volatile iodinated substance in the marine environment, other iodinated substances like CH2ClI, CH2I2 and CH3CH2CH2I exist in the range of 〈0.01 ng/L to 2.2 ng/L in surface water of the Atlantic Ocean. Although it is improbable that chlorophyll-a is directly involved in the marine production of halogenated hydrocarbons, it was found that it could be used as an indicator for the biogenic formation of brominated compounds, whereas the correlation between chlorophyll-a and the iodinated substances was not of the same quality. The positive correlation between bromoform and dibromomethane proves the same biogenic origin and mechanism of formation, which could not be found for the different iodinated compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050577
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Bromide/bromate speciation by NTI-IDMS and ICP-MS coupled with ion exchange chromatography (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 74-79 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  Two different mass spectrometric methods, negative thermal ionization isotope dilution mass spectrometry (NTI-IDMS) and inductively coupled plasma mass spectrometry (ICP-MS), off-line and on-line coupled with anion exchange chromatography, have been developed for simultaneous bromide and bromate determinations in water samples. The detection limits of these methods are in the range of 0.03–0.09 μg/L using a 50 mL sample.The results are independent of the content of other anions, which could be demonstrated by the analyses of six mineral waters containing chloride and sulfate of up to 160 mg/L and 1500 mg/L, respectively. Bromide has been analyzed by the NTI-IDMS method in the range of 10–500 μg/L and bromate in the range of 1–50 μg/L with relative standard deviations of 0.3–1.2% and 0.4–6%. Quantification for the ICP-MS method was carried out by the standard addition technique, which resulted in relative standard deviations of 5.5% for bromide at the 500 μg/L level and of 13% for bromate at the level of about 3 μg/L. These results are compared with those described in the literature for ion chromatographic (IC) and other methods and those obtained in this work by IC using UV detection, which allows high concentrations of chloride in the bromate fraction. The detection limits of this IC method are 6 μg/L for bromide and 30 μg/L for bromate. NTI-IDMS and ICP-MS therefore fit the recommendations of the European Union (detection limit〈2.5 μg/L; precision and accuracy better than 25% at the 10 μg/L level) for methods analyzing the carcinogenic bromate much better than IC and other methods applied up to now. As a definitive but time consuming method, NTI-IDMS is preferably applicable as a calibration technique, whereas ICP-MS, with relatively short analysis times, due to on-line coupling with chromatography, can be used as a sensitive and powerful routine method for trace bromide and bromate species in water samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050114
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...