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  • 1
    Electronic Resource
    Electronic Resource
    Thermal configurations of oxygen in silicon (1992)
    Springer
    Applied physics 55 (1992), S. 317-323 
    Details
    ISSN: 1432-0630
    Keywords: 61.70.−r ; 71.55.−i ; 81.40.−z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The central position and the infrared absorption coefficient of the 9 μm band of Si samples were measured with Fourier transform infrared spectroscopy (FTIR) at temperatures from T=77 K to 775 K. The infrared absorption coefficients were corrected by considering background absorption and free carrier absorption calculated from the increased free carrier concentration and from the resistivity determined from Hall effect measurements. We found the central position of the 9 μm band to shift to longer wavelengths with increasing temperature. The concentration [Oi] of interstitial oxygen is almost constant for T〈600 K, but decreased rapidly for T〉600 K. These results verified there are two types of thermal configurations of oxygen in silicon: The bonded Si2O configuration with a binding energy E b≈0.8 to 1.0 eV at T≈77 K to 600 K, and the Si2O configuration coexists with a quasi-free interstitial oxygen (QFIO) state for T〉600 K. The lattice potential barrier E L, which retards QFIO atoms from migrating in the lattice, is estimated to be 1.5 to 1.6 eV. From these configurations the anomalous diffusivity of oxygen in silicon can be explained quite well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324078
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  • 2
    Electronic Resource
    Electronic Resource
    New shallow donors in high-purity silicon single crystal (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2084-2086 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High-resolution photothermal ionization spectroscopy has been performed on n-type high-purity silicon crystals. Two new shallow donors with binding energies of 36.61 and 36.97 meV, respectively, are observed for the first time, in addition to lithium (Li), lithium-oxygen complex [D(Li,O)], phosphorus (P), and arsenic (As) donors. These new shallow donors show similar spectral features to Li, D(Li,O), P, and As, which implies that they are also hydrogenic shallow donors. These new complex centers are probably generated during crystal growth. In addition, previously unresolved transitions related to very high excited states of phosphorus as well as the above-mentioned new shallow donors, have also been observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102090
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  • 3
    Electronic Resource
    Electronic Resource
    Nitrogen-oxygen complexes in silicon studied by photothermal ionization spectroscopy (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 2260-2262 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High-resolution photothermal ionization spectroscopy has been performed on silicon grown in a nitrogen environment by the Czochralski technique for the first time. Three shallow donors related to the complexes of nitrogen and oxygen impurities D(N-O-3), D(N-O-4), and D(N-O-5) have been observed. Previously unresolved transitions related to the excited states higher than 3p± for D(N-O)s are observed in the spectra as well. The ionization energies of D(N-O)s have been accurately determined as 36.16, 36.41, and 37.37 meV, respectively. In addition, two previously unidentified donor levels found in the absorption spectra of silicon crystal involving nitrogen and oxygen are identified as originating from the splitting of the ground state of phosphorus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106090
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  • 4
    Electronic Resource
    Electronic Resource
    Existence of several homologous sequences in the Escherichia coli chromosome to the gene for the major outer membrane lipoprotein
    Amsterdam : Elsevier
    FEBS Letters 137 (1982), S. 168-170 
    Details
    ISSN: 0014-5793
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-5793(82)80340-2
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  • 5
    Electronic Resource
    Electronic Resource
    Gel formation in mullite precursors obtained via tetraethylorthosilicate (TEOS) pre-hydrolysis (1997)
    Springer
    Journal of materials science 32 (1997), S. 105-110 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Tetraethylorthosilicate (TEOS) and aluminium chloride were taken as sources of SiO2 and Al2O3 to prepare precursors of mullite by pre-hydrolysis of TEOS under refluxing conditions. Gelation was carried out at different pH values and the effect of the pH of gelation on the subsequent temperature-induced phase transformations was characterized by differential thermal analysis, powder X-ray diffraction and 29Si and 27Al solid-state nuclear magnetic resonance spectroscopy. A pH-dependent exothermic peak was observed at ∼980°C. Strong acidic conditions (pH=1.5) were found to be beneficial for improving the mixing scale of the Al–Si components, leading to a mullitization temperature of ∼1200° and a sharp 980°C exothermic peak. In strong basic conditions (pH=11.5), no evident ∼980°C exothermic peak was detected, and the mullitization temperature was as high as 1350°C, probably due to heterogeneity in the mixing scale of the Al–Si components in the precursor system. A gel formation process has been proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018575115770
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  • 6
    Electronic Resource
    Electronic Resource
    Augmentation of various immune reactivities of tumor-bearing hosts with an extract ofCordyceps sinensis (1990)
    Springer
    Biotherapy 2 (1990), S. 199-205 
    Details
    ISSN: 1573-8280
    Keywords: anti-tumor immunity ; macrophage chemotaxis ; Cordyceps extract ; EL-4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to enhance general reactivity of immune system in the tumor-bearing host, we employed extract ofCordyceps sinensis (CSE) as a biological response modifier.Cordyceps sinensis is an interesting material produced by a kind of mushroom parasitic to larval moths and was used to hasten recovery from exhaustion in ancient China. In this experiment, C57BL/6 mice implanted subcutaneously with syngeneic EL-4 lymphoma cells were employed as the host. Oral administration of the extract leads to a reduction of tumor size and prolongation of the host survival time. As judged by plaque-forming cells against T-dependent (sheep erythrocytes) and T-independent (bacterial lipopolysaccharide) antigens, CSE showed to augment the antibody responses. As for the activities of peritoneal macrophages, chemotaxis was dramatically depressed within a few days after EL-4 transplantation up to the end of life, but treatment with CSE at −14, −7, −4, +4, +7 and +10 days after the tumor transplantation augmented the activity about four times stronger than that of control. Phagocytic activity of macrophages was also decreased in tumor-bearing mice treated with cyclophosphamide (100 mg/kg) 3 and 5 days after tumor transplantation. But administration of CSE restored the activity to more than the normal level. The overall efficacy of CSE was tested with protective activity against systemic infection bySalmonella enteritides. The tumor-bearing mice receiving this medicine lived significantly longer than any other groups without CSE.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02173520
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  • 7
    Electronic Resource
    Electronic Resource
    Nucleotide sequence of a 1446 base pair SalI fragment and structure of a novel early gene ofLeucania seperata nuclear polyhedrosis virus (1995)
    Springer
    Archives of virology 140 (1995), S. 2283-2291 
    Details
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 1446 bp SalI fragment of LsNPV was sequenced by the silver staining method, and two large open reading frames (ORFs, ORF1 and ORF2) were found, both contain typical characteristics of the 5′ regulatory elements of baculovirus early genes. ORF1 is 345 bp long with the capacity to encode a putative protein of 114 amino acid residues with MW about 13 kDa and was designated p13 gene, ORF2 comprises 248 bp from the 3′ end of the fragment. In the untranslated region (UTR) of ORF1, a 33 bp mini cistron (ORF3), a core recognition sequence (CGTCG) for many bHLHzip transcription factors and a late promoter sequence TTAAG are present. In the UTR of ORF2, two host transcription factor binding elements (CACGTG and GATA motif) and two CGT motifs were found. Some regular leucine zipper-like structures, designated leucine trans-conformation structure and LVT repeat, were found near the N-terminus and the middle of p13 protein. The leucine trans-conformation structure that is near the N-terminus consists of 4 leucines and 7 other amino acids between every two leucines, and every leucine is located at a conformation shift point of the predicted secondary structure of the p13 protein. In LVT repeat, L-6aa-V-6aa-T-6aa is repeated once. The functions of those structures remain unclear, and the two ORFs, not found in the genome ofAutographa californica nuclear polyhedrosis virus, are possibly two new genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323248
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  • 8
    Electronic Resource
    Electronic Resource
    Photothermal ionization spectroscopy for shallow impurities in ultra-pure silicon (1990)
    Springer
    International journal of infrared and millimeter waves 11 (1990), S. 595-630 
    Details
    ISSN: 1572-9559
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the comprehensive results obtained in our group and last few years for the shallow impurities in ultrapure silicon by use of photothermal ionization spectroscopy. The new results reported here include the discovery and investigation of new shallow impurity centers in Si, the detection for the compensation of different types of impurities, the accurate determination for the spin-orbit splitting Δ. of valence band for Si, and the phonon duplicates and Fano resonance for the transitions of shallow impurities in Si. In addition it is also shown experimentally that the sensitivity of the photothermal ionization spectroscopy as used for detecting the concentration of shallow donors in Si can reach as high as 108 cm−3, much higher than that reported in the literatures up to date, and line width for the sharpest spectral lines in the spectrum is about 0.08 cm−1, that is, 10 μeV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01023764
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  • 9
    Electronic Resource
    Electronic Resource
    Inhibitory effect of alumina additive on the titania phase transformation of a sol--gel-derived powder (1997)
    Springer
    Journal of materials science 16 (1997), S. 1933-1935 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018590701831
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