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71.
Phase equilibria being established in the subsolidus area of the V2O5?Cr2(MoO4)3 system at the whole component concentration range have been studied basing on DTA and X-ray phase powder diffraction. It has been established that the system is not a real two-component system in the subsolidus area. The fact has been proved by the presence of fields in that area, where three solid phases remain in mutual equilibrium. 相似文献
72.
Leboda R Charmas B Skubiszewska-Zieba J Chodorowski S Oleszczuk P Gun'ko VM Pokrovskiy VA 《Journal of colloid and interface science》2005,284(1):39-47
Natural bentonite spent in the process of plant oil bleaching was used as an initial material for preparation of carbon-mineral adsorbents. The spent bleaching earth was treated using four procedures: T (thermal treatment); H (hydrothermal treatment); C (thermal treatment with addition of CCl4 vapor); M (modification of porous structure). Raw bentonite, RB (raw bleaching earth), and carbon materials prepared using plant oil were compared. The physicochemical characteristics of the adsorbents were determined using different methods: nitrogen adsorption/desorption, XRD, TEM, and MS-TPD. Carbon-mineral adsorbents contain from 5.23 to 19.92% C (w/w) and carbon adsorbents include from 84.2 to 91.18% C (w/w). Parallel processes of organic substance carbonization, porous structure modification, sublimation or evaporation of metal chlorides, and removal of hydrogen chloride take place during pyrolysis of waste mineral materials in the CCl4 atmosphere. 相似文献
73.
M. Kmiecik A. Maj B. Herskind A. Bracco R.A. Bark M. Bergström F. Camera G. Hagemann N. Hashimoto A. Holm S. Leoni T. Saitoh T.S. Tveter 《The European Physical Journal A - Hadrons and Nuclei》1998,1(1):11-13
The decay of 170W* formed in reactions with two different projectile - target combinations was studied. The observed differences in the average
number of emitted neutrons suggest an entrance channel effect at the highest excitation energy and angular momentum. It may
be explained by different excitation energies of the equilibrated system, resulting from the emission of pre-equilibrium α-particles
during a longer fusion time, in the more symmetric reaction.
Received: 30 October 1997 相似文献
74.
Tomasz Gubica Jadwiga Stroka Andrzej Temeriusz 《Journal of Physical Organic Chemistry》2007,20(6):375-383
A series of nitrophenyl β‐cyclodextrin derivatives: mono[6‐deoxy‐6‐(4‐nitrobenzamido)]‐per‐ O‐methyl‐β‐cyclodextrin (R1? Ph? NO2), mono[6‐deoxy‐6‐(3‐nitrobenzamido)]‐per‐O‐methyl‐β‐cyclodextrin (R2? Ph? NO2) and heptakis[6‐deoxy‐6‐(4‐nitrobenzamido)‐2,3‐di‐O‐methyl]‐β‐cyclodextrin [R3? (Ph? NO2)7] were synthesized. Purity and composition of the obtained substances were checked. Electroreduction of nitro groups of the new synthesized compounds was investigated on mercury electrode using cyclic voltammetry and chronocoulometry. The parameters of the reduction processes of ? NO2 groups of the investigated compounds were found not to be comparable to the reduction of nitrobenzene under the same experimental conditions. Moreover, the electroreduction of nitro groups in these nitrophenyl derivatives was dependent on pH, the type of the studied compound, and slightly on the solvent composition. All the reactants were strongly adsorbed on mercury electrode. In the case of R3? (Ph? NO2)7, its seven nitro groups were reduced practically at the same potential, and no radical anion formation was observed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
75.
Sherie?L?KendallEmail author Caroline?F?Anderson Avindra?Nath Jadwiga?Turchan-Cholewo Cantey?L?Land Charles?F?Mactutus Rosemarie?M?Booze 《BMC neuroscience》2005,6(1):40
Background
HIV Associated Dementia (HAD) is a common complication of human immunodeficiency virus (HIV) infection that erodes the quality of life for patients and burdens health care providers. Intravenous drug use is a major route of HIV transmission, and drug use is associated with increased HAD. Specific proteins released as a consequence of HIV infection (e.g., gp120, the HIV envelope protein and Tat, the nuclear transactivating protein) have been implicated in the pathogenesis of HAD. In primary cultures of human fetal brain tissue, subtoxic doses of gp120 and Tat are capable of interacting with a physiologically relevant dose of cocaine, to produce a significant synergistic neurotoxicity. Using this model system, the neuroprotective potential of gonadal steroids was investigated. 相似文献76.
Devos A Lukas L Suykens JA Vanhamme L Tate AR Howe FA Majós C Moreno-Torres A van der Graaf M Arús C Van Huffel S 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2004,170(1):164-175
The purpose was to objectively compare the application of several techniques and the use of several input features for brain tumour classification using Magnetic Resonance Spectroscopy (MRS). Short echo time 1H MRS signals from patients with glioblastomas (n = 87), meningiomas (n = 57), metastases (n = 39), and astrocytomas grade II (n = 22) were provided by six centres in the European Union funded INTERPRET project. Linear discriminant analysis, least squares support vector machines (LS-SVM) with a linear kernel and LS-SVM with radial basis function kernel were applied and evaluated over 100 stratified random splittings of the dataset into training and test sets. The area under the receiver operating characteristic curve (AUC) was used to measure the performance of binary classifiers, while the percentage of correct classifications was used to evaluate the multiclass classifiers. The influence of several factors on the classification performance has been tested: L2- vs. water normalization, magnitude vs. real spectra and baseline correction. The effect of input feature reduction was also investigated by using only the selected frequency regions containing the most discriminatory information, and peak integrated values. Using L2-normalized complete spectra the automated binary classifiers reached a mean test AUC of more than 0.95, except for glioblastomas vs. metastases. Similar results were obtained for all classification techniques and input features except for water normalized spectra, where classification performance was lower. This indicates that data acquisition and processing can be simplified for classification purposes, excluding the need for separate water signal acquisition, baseline correction or phasing. 相似文献
77.
78.
Damian Pociecha Jadwiga Szydlowska Julita Gasowska Dorota Kardas J zef Mieczkowski Wieslaw Tlaczala 《Liquid crystals》2002,29(5):663-667
Two homologous series of mesogenic materials with molecules containing an amide moiety, cyclic or symmetrically branched, as the terminal group have been synthesized. Materials of both series form lamellar liquid crystal phases. It was observed that elongation of the amide chains in 'fork-like' compounds destabilizes the mesophases, while 'cyclic' materials, even with quite large terminal amide rings, exhibit enantiotropic liquid crystalline phases. 相似文献
79.
Ajita M. Abeysekera Ronald Grigg Jadwiga Trocha-Grimshaw Kim Henrick 《Tetrahedron》1980,36(12):1857-1868
Improved procedures are reported for the preparation of mono-, di- and tri-N-methyl-etioporphyrin I. Demethylation of Na, Nb, Nc-trimethyletioporphyrin I under acidic, basic or thermal conditions gives Na, Nb-dimethyl etioporphyrin I. N-Methylation of octaalkyl-5-azaporphyrins leads, in general, to mixtures of the isomeric mono-, di- and tri-N-alkylated 5-azaporphyrins. An X-ray crystal structure of Na,Nb-dimethyl etioporphyrin I triiodide confirms the trans arrangement of the N-Me groups. The two N-methylated pyrrole rings are twisted 27° to each other. 相似文献
80.
Anomalous S2 → S0 fluorescence and T2 → S0 phosphorescence have been found in several triphenylmethane derivatives. This phenomenon can be explained by a large energy gap between the S2 and S1 levels, approximately 14000 cm?1. Some of the investigated compounds exhibit also a normal long-wave fluorescence in spite of the fact, that the S2 ? S1 energy gap does not change significantly. However, in these cases absorption spectra reveal a high oscillator strength of the S1 → S0 transition. The coordination of a lanthanide ion quenches in several cases the normal S1 → S0 fluorescence whereas the S2 → S0 one is not affected significantly. 相似文献