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1Author    M. Suwalsky, N. Bugueñ, J. Tapia, F. NeiraRequires cookie*
 Title    X-Ray Studies on Phospholipid Bilayers. V. Interactions with DDT  
 Abstract    The possible interaction of DDT with the lipids dimyristoyl lecithin (DML), dipalmitoylphos-phatidylethanolamine (DPPE) and tripalmitin (TP) was studied. The work was carried out on oriented films and crystalline powders of DDT-lipid mixtures at different molar ratios by X-ray diffraction techniques. The diagrams showed only the patterns of pure DDT and that of the corresponding lipid. It is concluded that new phases were not formed and, therefore, no interac­ tions occurred. 
  Reference    Z. Naturforsch. 40c, 566—570 (1985); received March 29 1985 
  Published    1985 
  Keywords    X-Ray Diffraction, Lipid, Bilayer, DDT, Pesticide 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0566.pdf 
 Identifier    ZNC-1985-40c-0566 
 Volume    40 
2Author    Hiroyuki Ishida, Hironobu Maeda, Akiko Hirano, Tamotsu Fujimoto, Yoshihiro Kubozono, Setsuo Kashino, Shuichi EmuraRequires cookie*
 Title    E X A F S S tu d y o n th e P h a s e T r a n s itio n ( P h a s e a ' -5) in C H 3 N H 3 I  
 Abstract    The local structure of CH3NH3I around the I" ion in Phase a 'and 8 was studied by iodine K-edge EXAFS. The crystal structure in Phase a ' was redetermined by single crystal X-ray diffraction. The Debye-Waller factor <r(2) derived from EXAFS spectra shows an anomalous behavior around the order-disorder transition temperature from Phase 8 to a '. The phase transition has been interpreted as the disordering process which involves not only the H atoms but also the C atoms in the cation. 
  Reference    Z. Naturforsch. 50a, 876—880 (1995); received June 16 1995 
  Published    1995 
  Keywords    Crystal structure, EXAFS, Phase transition, X-ray diffraction 
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 TEI-XML for    default:Reihe_A/50/ZNA-1995-50a-0876.pdf 
 Identifier    ZNA-1995-50a-0876 
 Volume    50 
3Author    M. Maeda, T. Ito, M. Hori, G. JohanssonRequires cookie*
 Title    The Structure of Zinc Chloride Complexes in Aqueous Solution  
 Abstract    The structure of zinc chloride complexes with different ratios of chloride to zinc, formed in concentrated ZnCl 2 aqueous solutions, were determined from large-angle X-ray scattering using concentrations of the chloride complexes estimated by complementary Raman spectroscopic mea-surements. The highest chloro complex, [ZnCl 4 ] 2 ~, is tetrahedral with a Zn-Cl bond length of 2.294(4) Ä. The trichloro complex, [ZnCl 3 ]~, which coordinates one water molecule, is pyramidal with the Cl-Zn-Cl angle 111°. The Zn-Cl and the Zn-H 2 0 bonds are 2.282(4) and 1.9 A, respec-tively. The two lower complexes, [ZnCl 2 ] and [ZnCl] + , cannot be separated by Raman spectra. o The average Zn-Cl distance in these complexes is 2.24 Ä, and the average Zn-H 2 Ö distance is 1.9 A. In [Zn(H 2 0) 6 ] 2+ the Zn-H 2 0 distance is 2.15 Ä. of zinc (II) chloride complexes; structure of hydrated non-complexed zinc (II) ion. 
  Reference    Z. Naturforsch. 51a, 63—70 (1996); received November 7 1995 
  Published    1996 
  Keywords    X-ray diffraction, Raman spectra, IR spectra, structures 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0063.pdf 
 Identifier    ZNA-1996-51a-0063 
 Volume    51 
4Author    Carla Cannas, Giorgio Concas, Anna Musinu, Giorgio Piccaluga, Giorgio SpanoRequires cookie*
 Title    Mössbauer Spectroscopic Study of Fe 2 0 3 Nanoparticles Dispersed over a Silica Matrix  
 Abstract    A series of Fe 2 0 3 -Si02 nanocomposites (9 -33 wt% of Fe 2 0 3) has been prepared by a sol-gel method and submitted to thermal treatments at 300 -900 °C. The samples were characterized by X-ray diffraction and Mössbauer Spectroscopy measurements. Superparamagnetic behavior is exhibited by all the samples, indicating that the size of iron oxide grains is in the nanometer range (4-6 nm). Increase of iron content and temperature treatment give rise to a small particle growth, while the spread of sizes around the average value increases with the iron concentration. The Mössbauer spectra, at all the explored compositions, show a very steep increase of the peak width by treatment temperature at 900 °C, indicating the formation of the ferrimagnetic 7-Fe 2 0 3 phase from the antiferromagnetic amorphous Fe 2 0 3 phase, which dominates in the samples treated at lower temperatures. The samples at 28.5% and 33.2%, treated at 900 °C, also show a component of 7-Fe 2 0 3 in the blocked state at room temperature. Moreover, the growth of the particles favours the formation of other oxide phases (a and £ phase) along with the 7 phase. 
  Reference    Z. Naturforsch. 54a, 513—518 (1999); received June 28 1999 
  Published    1999 
  Keywords    Nanocomposite, Ferric Oxide, Mössbauer Spectroscopy, X-ray Diffraction 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0513.pdf 
 Identifier    ZNA-1999-54a-0513 
 Volume    54 
5Author    A. Pojtinger, P. Lamparter, S. SteebRequires cookie*
 Title    Structure of Sputtered Amorphous Zr-Hf-Si Alloys  
 Abstract    Amorphous (Zr,Hf)37Si 63 alloys were produced by sputtering. Their total structure factors were determined by X-ray diffraction. Using the methods of isomorphous substitution and Reverse Monte Carlo simulation, the partial pair correlation functions were obtained. The results were compared with the partial functions of amorphous Ti^Si^. In the amorphous alloys under inves-tigation the transition metal -metalloid correlation dominates the short range order. 
  Reference    Z. Naturforsch. 54a, 699—703 (1999); received November 2 1999 
  Published    1999 
  Keywords    Amorphous Zr-Hf-Si, X-ray Diffraction, RMC Model 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0699.pdf 
 Identifier    ZNA-1999-54a-0699 
 Volume    54 
6Author    J.Nomssi Nzali, W. HoyerRequires cookie*
 Title    X-ray Investigations of Liquid Bismuth-Copper Alloys  
 Abstract    Liquid copper, bismuth, and eleven bismuth-copper alloys were investigated at temperatures above the liquidus with X-ray diffraction. The experimental procedure was adjusted to reduce the effects of evaporation. The Faber-Ziman total structure factors S(Q) feature a splitting of the first maximum and negative values for Q around 1 A -1 in a large concentration range. The results are compared to previous neutron diffraction results by Zaiss and Steeb, to square-well potential model calculations by Gopala Rao and Satpathy and to a simple segregation model. The segregation model reproduces the features qualitatively. Partial structure factors are assessed by fitting both neutron and X-ray scattering results with reverse Monte-Carlo simulation. 
  Reference    Z. Naturforsch. 55a, 381—389 (2000); received May 29 1999 
  Published    2000 
  Keywords    Bismuth, Copper, Liquid Alloys, X-ray Diffraction, Microsegregation 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0381.pdf 
 Identifier    ZNA-2000-55a-0381 
 Volume    55 
7Author    Hiroyuki Ishida, Setsuo Kashino, Ryuichi IkedaRequires cookie*
 Title    Crystal Structure of Trimethylammonium Tetrafluoroborate in Three Solid Phases  
 Abstract    The crystal structure of (CH 3) 3 NHBF 4 was studied in three solid phases by X-ray diffraction techniques. The structures of the ionic plastic phase (Phase I) stable above 453 K and Phase II between 384 and 453 K are CsCl-type cubic (a = 5.772(4) Ä) and tetragonal (a = 9.815(5) and c = 6.895(5) A), respectively. The room temperature phase (Phase III) forms a monoclinic lattice (space group P2,/m, a = 5.7017(8), b = 8.5724(9), c = 7.444(1) Ä, and ß = 102.76(1)°). BF 4 ~ ions in this phase were shown to be disordered in four orientations. 
  Reference    Z. Naturforsch. 55a, 765—768 (2000); received June 28 2000 
  Published    2000 
  Keywords    Crystal Structure, X-ray Diffraction, Ionic Plastic Phase, Disorder 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0765.pdf 
 Identifier    ZNA-2000-55a-0765 
 Volume    55 
8Author    DouglasL. Dorset, WalterA. Pangborn, AnthonyJ. Hancock, IrisS. LeeRequires cookie*
 Title    Influence of Molecular Conformation on the Solid State Packing of 1,2-Diglycerides Study of 1,2-Dipalmitin and Some Structural Analogs by Electron Diffraction, X-Ray Diffraction, and Infrared Spectroscopy  
 Abstract    Diffraction studies on natural 1,2-dipalmitin and on analogs, including those based on the configurational isomers of cyclopentane-l,2,3-triol reveal that the 1,2-diglycerides crystallize from solvent with chain methylene packing identical to the monoclinic form of even-chain alkanes. The chains probably are folded back in "hairpin" fashion as found in phospholipid crystal structures. Acyl shifts are observed to occur in the crystalline solid state at room temperature to give the 1,3-diglyceride. Analogs based on the above-mentioned cyclitols show that isomers with adjacent chains trans to the ring (possibly extended chain packing) or with chains cis to the ring ("hair­ pin") crystallize readily. Both possibly extended chain configurational isomers have the a-form as well as /?'-forms and a /5-polymorph. The hairpin isomers each give a /?'-polymorph but only the all-cts isomer gives an «-form. 
  Reference    Z. Naturforsch. 33c, 39 (1978); received July 29/October 3 1977 
  Published    1978 
  Keywords    Diglycerides, Crystal Structure, Electron Diffraction, X-Ray Diffraction 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0039.pdf 
 Identifier    ZNC-1978-33c-0039 
 Volume    33 
9Author    DouglasL. Dorset, WalterA. Pangborn, AnthonyJ. Hancock, TonC. Van Soest, S. M. GreenwaldRequires cookie*
 Title    Glycerol Conformation and the Crystal Structure of Lipids II. A Further Study of Tripalmitin and Conformationally Fixed Analogs by Small-Angle X-Ray Diffraction and Reflection Electron Diffraction  
 Abstract    The utility of analogs to glycerol-containing lipids based on the configurational isomers of cyclo-pentane-l,2,3-triol for ab initio crystal structure analysis via electron diffraction is assessed further. Such analogs of tripalmitin are examined with the natural triglyceride via low angle X-ray diffrac­ tion. The 1,3/2 (all-irarcs) and 1,2/3 (cis-trans) analogs give long spacing dimensions some 23 Ä greater than found for the ß-2 form of the natural compound, consistent with the long spacing observed for a ß-3 form. The 1,2,3/0 (all-cis) analog gives a long spacing near that of the a-form of the triglyceride. Reflection electron diffraction measurements on the 1,3/2 and 1,2/3 analogs reveal a chain tilt near 60° for both and untilted chains for 1,2,3/0. A more accurate tilt determina­ tion from X-ray long spacings of the homologous series of 1,3/2 pseudotrilaurin to 1,3/2 pseudo-tripalmitin confirm the 67° tilt expected for the ß-3 form. Therefore, given the same T,, methylene subcell, the molecular packing is very close to natural triglycerides. The subtle influences of the cyclopentane ring are overcome for 1,3/2 analogs based on stearic and arachidic acids. This emphasizes the utility of these structural analogs for ab initio crystal structure determinations of glycerol containing lipids. 
  Reference    Z. Naturforsch. 33c, 50 (1978); received October ll/November 28 1977 
  Published    1978 
  Keywords    Triglycerides, Crystal Structure, X-Ray Diffraction, Electron Diffraction 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0050.pdf 
 Identifier    ZNC-1978-33c-0050 
 Volume    33 
10Author    M. Suwalsky, E. KnightRequires cookie*
 Title    X-Ray Studies on Phospholipid Bilayers. II. Polymorphic Forms of Dipalmitoyl Phosphatidylethanolamine  
 Abstract    Oriented films and powder samples of the phospholipid L-x-dipalmitoyl phosphatidylethanol­ amine (DPPE) were studied by X-ray fiber diffraction techniques. The specimens were photographed under a complete range of hydration at room temperature. Two polymorphic forms were found. One of them was present in oriented films. It showed a close packing of DPPE molecules lying parallel to the normal to the bilayer plane. The other form, observed in the powder samples, had the molecules tilted by about 25°. Both forms were characterized by their unit cell dimensions, space groups, molecular conformations and packing arrangements. 
  Reference    Z. Naturforsch. 37c, 1157—1160 (1982); received June 2/August 16 1982 
  Published    1982 
  Keywords    Phospholipid, Bilayers, X-Ray Diffraction, Dipalmitoyl Phosphatidylethanolamine, Membrane 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1157.pdf 
 Identifier    ZNC-1982-37c-1157 
 Volume    37 
11Author    DouglasL. DorsetRequires cookie*
 Title    How Different are the Crystal Structures of Chiral and Racemic Diacylphosphatidylethanolamines?  
 Abstract    Both chiral and racemic phosphatidylethanolamines are known to crystallize in a similar poly-morphic form with nearly the same lamellar spacing; yet published lamellar X-ray diffraction intensity data for those materials do not agree with one another, even though the peak positions in Patterson maps are nearly the same. Translational structural searches based on the crystal struc-ture of the racemic compound also lead to similar packing models with both data sets, although the agreement between model and observed data is poor for the chiral compound. A separate analysis of L-DMPE based on lamellar electron diffraction data again leads to a similar lamellar structure with a better agreement between calculated and observed structure factors. The major difference seen for enantiomeric vs. racemic compounds is that, for the racemic lipid, the lateral unit cell spacings are about 3% larger than the chiral form, perhaps indicating a more stable hydrogen bonding network, in agreement with the higher melting point of the racemic compound. Attempts to explain this difference with other head group conformations, however, have not yet produced an improved structural model. 
  Reference    Z. Naturforsch. 43c, 319—327 (1988); received November 20 1987 
  Published    1988 
  Keywords    Phospholipids, X-Ray Diffraction, Electron Diffraction 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0319.pdf 
 Identifier    ZNC-1988-43c-0319 
 Volume    43 
12Author    M. Suwalsky, L. Gimenez, V. Saenger, F. NeiraRequires cookie*
 Title    X-Ray Studies on Phospholipid Bilayers. VIII. Interactions with Chlorpromazine * HCl  
 Abstract    Chlorpromazine is a widely used phenothiazine tranquilizer known to alter the shape of normal erythrocytes and their osmotic fragility. In order to understand the nature of the interactions chlorpromazine • HCl (CPZ HCl) was made to interact with phospholipid bilayers formed by dimyristoylphosphatidylethanolamine (DMPE) and dimyristoylphosphatidylcholine (DMPC). This study was carried out by X-ray diffraction on crystalline powders of various molar mixtures of CPZ -HCl with DMPE and DMPC, with and without water. It was found that CPZ -HCl significa-tively affects the bilayer structure of DMPC in the presence of water, but not that of DMPE. 
  Reference    Z. Naturforsch. 43c, 742—748 (1988); received March 23/June 13 1988 
  Published    1988 
  Keywords    X-Ray Diffraction, Phospholipid, Bilayer, Chlorpromazine @BULLET HCl 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0742.pdf 
 Identifier    ZNC-1988-43c-0742 
 Volume    43 
13Author    M. Suwalsky, I. Sánchez, F. NeiraRequires cookie*
 Title    X-Ray Studies on Phospholipid Bilayers. XIV. Interactions with the Antiarrhytmic Asocainol  
 Abstract    Asocainol (ASOC) belongs to class I of the antiarrhytmic drugs, i.e., those that exert their action at the level of the sodium channels of the myocardial cell membrane. It has been sug­ gested that their molecular mechanism of action might be through nonspecific interactions with phospholipids that surround the channel proteins. In order to test this hypothesis, ASOC was made to interact with two multibilayer systems, one built-up o f dimyristoylphosphat-idylcholine (DMPC) and the other of dimyristoylphosphatidylethanolamine (DMPE). These are the type of lipids that are respectively found in the outer and inner monolayers o f human erythrocytes. The experiments were carried out in a hydrophobic as well as in a hydrophilic medium below the phospholipid main transition temperatures. The perturbing effect of ASOC upon the bilayer structures was determined by X-ray diffraction. It was found that ASOC was able to fluidize DMPC in both media but not to DMPE. 
  Reference    Z. Naturforsch. 48c, 930—938 (1993); received June 30/September 1 1993 
  Published    1993 
  Keywords    X-Ray Diffraction, Phospholipid Bilayer, Antiarrhytmic, Asocainol 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0930.pdf 
 Identifier    ZNC-1993-48c-0930 
 Volume    48 
14Author    Yoshihiro Okamoto, Toru OgawaRequires cookie*
 Title    Structure and Dynamic Properties of Molten Lanthanum Tribromide  
 Abstract    The structure of molten LaBr 3 was investigated by X-ray diffraction and molecular dynamics simu-lations. It was found that the short range structure of molten LaBr 3 is very similar to that of molten LaCl 3 , except for some structural features such as interionic distances based on the difference of anion sizes. In the MD simulation, the shear viscosity of molten LaBr 3 was estimated from the structurally-optimized MD calculations. 
  Reference    Z. Naturforsch. 54a, 91—94 (1999); received November 27 1998 
  Published    1999 
  Keywords    Molten Salt, Rare Earth Halide, X-ray Diffraction, Molecular Dynamics 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0091.pdf 
 Identifier    ZNA-1999-54a-0091 
 Volume    54 
15Author    W. Müller-Klieser, W. KreutzRequires cookie*
 Title    O n the Cross-Section Structure of the Mitochondrial Cristae-Membrane as Revealed by X-Ray Diffraction  
 Abstract    Mitochondria were isolated using sorbitol and high buffer concentration in the medium. X-ray diffraction patterns arising from the mitochondrial cristae-membrane were recorded in the fully dried state and in two different states in humidity. The (Munction evaluation of these X-ray dif­ fraction diagrams resulted in electron density cross-section profiles, which consist of two main peaks of opposite sign and one, respectively two, brane amounts to 120 Ä in the dry and 140 Ä to cross-section profile is tentatively proposed. 
  Reference    (Z. Naturforsch. 31c, 612 [1976]; received July 16 1976) 
  Published    1976 
  Keywords    Biomembranes, Mitochondria, X-Ray Diffraction, (^-Function, Electron Density Profile 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0612.pdf 
 Identifier    ZNC-1976-31c-0612 
 Volume    31 
16Author    R. Jonak, ChM. Lapière, A. Meinel, H. Nemetschek-Gansler, Th Nemetschek, H. RiedlRequires cookie*
 Title    Struktur und mechanische Eigenschaften dermatosparaktischen Kollagens Structure and Mechanical Properties of Dermatosparactic Collagen  
 Abstract    Dermatosparactic calf-tail-tendon-collagen was investigated by mechanical measurements, elec­ tron microscopy and x-ray diffraction. We suppose, that the tensile strength decrease of the fibres is due to the irregular aggregation of subfibrils to fibrils. The x-ray diagram of the fibre is not influenced by state of disorder. Cyclic extension of dermatosparactic collagen leads to a higher increase in tensile strength than in the case of normal calf tendon. The effect might be due to the increase of fibril-and area-density resulting in an augmentation of crosslinks. 
  Reference    (Z. Naturforsch. 32c, 743 [1977]; eingegangen am 29. Juli 1977) 
  Published    1977 
  Keywords    Collagen, Dermatosparaxis, Mechanical Behaviour, Thermal Stability, x-Ray Diffraction 
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 TEI-XML for    default:Reihe_C/32/ZNC-1977-32c-0743.pdf 
 Identifier    ZNC-1977-32c-0743 
 Volume    32 
17Author    Giorgio Concas, Francesco Congiu, Anna Corrias, Carlo Muntoni, Giorgio Paschina, Daniela ZeddaRequires cookie*
 Title    Investigation of the Reaction between Fe 2 0 3 and Si Activated by Ball Milling  
 Abstract    The path of the reaction between Fe 2 0 3 and Si, activated by high energy ball milling, has been investigated by X-ray diffraction and Mössbauer spectroscopy. Hematite reduction involves oxygen transfer from Fe to Si with the formation of intermediate phases containing Fe(II), which are then reduced to Fe(0). A steady state is reached in the milling process where the reduction of stoichiomet-ric amounts of Fe 2 0 3 and Si is not complete and an amount of Fe(II) in an amorphous matrix still remains. The same intermediate compounds are also observed in the milling process of mixtures with higher Fe 2 0 3 /Si molar ratio. 
  Reference    Z. Naturforsch. 51a, 915—922 (1996); received April 1 1996 
  Published    1996 
  Keywords    Mechanosynthesis, Nanocomposite, Reduction reaction, Mössbauer spectroscopy, X-ray diffraction 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0915.pdf 
 Identifier    ZNA-1996-51a-0915 
 Volume    51 
18Author    Uwe Hoppe, Günter Walter, Dörte Stachel, Andrea Barz, AlexC. HannonRequires cookie*
 Title    Neutron and X-ray Diffraction Study on the Structure of Ultraphosphate Glasses  
 Abstract    The high real-space resolution of neutron diffraction experiments which is provided by use of the epithermal neutrons from spallation sources was exploited in order to differentiate the unlike P-O bonds existing in the P0 4 units of phosphate glass networks. The 2 P-O distance peaks, separated by about 12 pm, which were found in the zinc and the calcium ultraphosphate glasses studied are assigned to oxygen sites on bridging (O b) and terminal (O X) positions. The mean P-O distances are nearly invariable versus the growing metal oxide content which results from an elongation of the P-O b and P-O t bonds. The bond lengths which are known from the related crystal structures and from ab initio calculations show almost the same behaviour. The discussion of further details of the crystal structures leads to the conclusion that P-O b rather than P-O t distances should show more details in case of diffraction measurements of even higher real-space resolution. The change of the Zn-O coordination number from 6 to 4 versus increasing ZnO content, which was obtained in previous X-ray diffraction experiments, is confirmed by the recent combination of neutron and X-ray diffraction data. On the other hand, the Ca-O coordination number of about 6 is almost invariable. 
  Reference    Z. Naturforsch. 52a, 259—269 (1997); received July 6 1996 
  Published    1997 
  Keywords    Neutron diffraction, X-ray diffraction, Phosphate glasses, Short-range order 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0259.pdf 
 Identifier    ZNA-1997-52a-0259 
 Volume    52 
19Author    G. A. Ennas, Falqur, G. Piccaluga, S. Solinas, D. Gatteschi, C. Sangregorio, A. BenedettiRequires cookie*
 Title    Properties of Nanocrystalline Nickel Particles in Ni-Si0 2 Composites  
 Abstract    Nickel-Silica nanocomposites with a nickel content equal to 10, 15, 20 wt% have been prepared by a sol-gel method starting from ethanolic solutions of tetraethoxysilane and nickel nitrate hex-ahydrate. After selation the samples were reduced in H-> flow at selected temperature (450 °C < T < 600 °C). The morphological, structural and magnetic properties were investigated by transmission electron microscopy (TEM), wide and small angle X-ray scattering (WAXS, SAXS), magnetic susceptibility in zero field cooled and field cooled mode (ZFC and FC), and magnetic hysteresis loop. Nanometric nickel particles are observed in all the investigated samples. TEM, WAXS and SAXS techniques indicate that the average nickel particle size grows slightly but almost regularly with the nickel concentration. TEM results moreover indicate that also the width of the particle size distribution, which can be simulated by log-normal functions, follows this trend. All the sample treated in hydrogen show superparamagnetic behaviour. The magnetisation falls to reach saturation up to highest measuring field of 70 kOe even at 3 K, while the observed coercivity H c is much higher than the theoretical bulk one. Some uncertainty in the complete interpretation of the sequence of magnetic measurements is attributed to a progressive oxidation of the samples when these are air exposed. 
  Reference    Z. Naturforsch. 55a, 581—588 (2000); received March 9 2000 
  Published    2000 
  Keywords    Nanocomposites, Nickel-Silica, X-ray Diffraction, TEM, Magnetic Properties 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0581.pdf 
 Identifier    ZNA-2000-55a-0581 
 Volume    55 
20Author    R. Hosemann, J. Loboda-Čačković, H. Č. Ačković, S. F. Ernandez-Berm, F. J. Údez, Baltá-CallejaRequires cookie*
 Title    Structure of Cerebrosides. II. Small Angle X-Ray Diffraction Study of Cerasine  
 Abstract    Cerasine having a molecular weight of 800 differs chemically from phrenosine only in the hy­ droxyl group attached to the fatty acid tail which is replaced by a hydrogen atom. Nevertheless, remarkable differences between both cerebrosides are detected in the lamellae periodicities. In the range of 23 — 66 °C just one single (instead of two) structure with a sim ilar subcell to the triclinic one component of phrenosine is detected. Between 66 and 87 °C three new components (instead of one in phrenosine) appear. Two of the structures are sim ilar to the two phrenosine-components at low tem perature and the tilt angles of their chains with respect to the basal planes can explain the stabilizing capacity of the 201 and 301 netplanes o f the paraffin-like subcells respectively. These lattice planes are parallely aligned to the surfaces o f the lamellae. The long period of 58 A of component II cannot be explained in such a way. This period persits upto 105 °C and coexists from 87 °C with a new com ponent showing a 40 A -periodicity, which cannot either be explained in the above manner. Paracrystalline distortions of the arrangem ent of the bilayers can be justified by orientational disorder of the galactose heads. 
  Reference    Z. Naturforsch. 34c, 1121—1124 (1979); received July 6 1979 
  Published    1979 
  Keywords    Cerebrosides, Lipid Bilayers, X-Ray Diffraction, Long Period, Paracrystalline Distortions 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1121.pdf 
 Identifier    ZNC-1979-34c-1121 
 Volume    34 
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