Showing papers by "United States Department of Energy published in 1979"

Rational synthesis of unidimensional mixed valence solids. Structural, spectral, and electrical studies of charge distribution and transport in partially oxidized nickel and palladium bisdiphenylglyoximates

Abstract: A detailed study is presented of solid-state structure, oxidation state, and electron transport in Ni(dpg)/sub 2/I and Pg(dpg)/sub 2/I, dpg = diphenylglyoximato. The crystal structure of Ni(dpg)/sub 2/I has been studied by x-ray diffraction at 23 and -160/sup 0/C. The compound crystallizes in the tetragonal space group D/sub 4h//sup 8/-P4/ncc, with four formula units of Ni(dpg)/sub 2/I in a unit cell having dimensions at -160/sup 0/C of a = 19.774 (8), c = 6.446 (3) A. Full-matrix least-squares refinement of 31 variables gave a final value of the conventional R index (on F) of 0.093 for 353 reflections having F/sub 0//sup 2/ > 3 sigma(F/sub 0//sup 2/). The crystal structure consists of stacked Ni(dpg)/sub 2/ units (staggered by 90/sup 0/) and disordered chains of iodine atoms extending in the c direction. At -160/sup 0/C the Ni--Ni separation is 3.223 (2) A; other important distances are Ni--N = 1.868 (15), N--C = 1.33 (3), N--O = 1.34 (3) A. The Ni(dpg)/sub 2/ moiety is decidedly nonplanar (D/sub 2/ symmetry) with coordinated N atoms displaced 0.12 (2) A above or below the mean molecular plane. Analysis of diffuse x-ray scattering associated with the disordered iodine chains is consistent with I/sub 5//sup -/more » being the predominant species. This result is in agreement with resonance Raman spectroscopic studies on Ni(dpg)/sub 2/I and Pd(dpg)/sub 2/I as well as on model compounds. Fundamental polyiodide transitions in the M(dpg)/sub 2/I materials are observed(..nu../sub 0/ = 4880--6471 A)at 161 vs and 107 w cm/sup -1/; weak M(dpg)/sub 2/-centered scattering is also noted. Iodination brings about an increase in conductivity of > 10/sup 8/ (Ni) and > 10/sup 7/ (Pd), which is especially noteworthy since the only major change in crystal structure upon iodination is a ca. 0.27 A decrease in the M(dpg)/sub 2/ stacking distance. Variable-temperature studies show the Ni(dpg)/sub 2/I and Pd(dpg)/sub 2/I conductivities to be thermally activated.« less

Karyotypic abnormalities and clinical aspects of patients with multiple myeloma and related paraproteinemic disorders

Abstract: Karyotypic abnormalities were detected in the malignant cells of 6 of 18 patients with multiple myeloma (MM). Six patients with benign monoclonal gammopathy, one with amyloidosis of immunoglobulin origin, and two with Waldenstrom's macroglobulinemia had normal karyotypes. All six MM patients with aneuploidy were in a group of 10 patients in an accelerated or relapse phase of their disease and four had high serum paraprotein levels (7.92, 6.24, 6.80, and 4.24 g/dl, respectively) when their abnormal karyotypes were detected. Five of the 6 MM patients with aneuploidy had received prior chemotherapy. Aneuploidy was not observed in 8 stable MM patients. Abnormalities of chromosome 14 were present in all 6 patients, with a 14q+ marker in 5 and loss of No. 14 in 1. A translocation between Nos. 11 and 14 was found in aneuploid cells of 2 patients who had plasma cell leukemia (PCL). However, the break point in the long arm of No. 11 differed in the 2 patients. A gain of Nos. 5, 9, and 11 was seen in 3 patients, a gain of No 1 in 2, and rearrangements of No. 1 in 5 MM patients, including all 4 who had a 14q+ marker chromosome initially. A deletion of chromosome 6 at band q25 was detected in 2 MM patients and a pericentric inversion of No. 6 (6p21 to 6q13) was seen in the patient with PCL. Three of 4 MM patients had a nonrandom loss of one chromosome 8. Two other MM patients, who were treated with melphalan and prednisone, developed acute nonlymphocytic leukemia (ANLL) 2+ and 4+ years after the diagnosis of MM. Marrow cells of one patient showed a 5q- chromosome and a constitutional translocation involving Nos. 13 and 14 during the preleukemic stage; during the leukemic phase, the karyotype evolved to 50 chromosomes including extra chromosomes 1, 6, 8, 10, and 21 and a missing 7, in addition to the originally detected 5q- and the 13/14 translocation. The peripheral blood from the other patient was hypodiploid, with a missing chromosome 7 and a translocation between 3q and 9p. These patterns of chromosome change resemble those of ANLL rather than MM and are similar to the changes seen in ANLL after treated malignant lymphoma.

Electronic structure of metal hydrides. II. Band theory of Sc H 2 and Y H 2

Abstract: Self-consistent band-structure calculations have been performed for Sc${\mathrm{H}}_{2}$ and Y${\mathrm{H}}_{2}$ using the Korringa-Kohn-Rostoker method. The results indicate a net charge transfer from the metal to the hydrogen site and a concomitant raising of the hydrogen bonding bands relative to those obtained through non-self-conssitent calculations. Comparisons are made between the results of our calculations and the results of optical studies by Weaver, Rosei, and Peterson. Additional calculations were performed in which the Fermi level or band gaps were rigidly shifted by a small energy increment. These calculations were used to simulate the derivative structure obtained in thermomodulation spectra and helped to identify the $k$-space origin of several experimental interband features found in the thermoreflectance of Sc${\mathrm{H}}_{2}$ and Y${\mathrm{H}}_{2}$. The experimentally observed, low-energy, stoichiometry-dependent optical features of Y${\mathrm{H}}_{2}$, which had partially inspired our studies, were not interpretable within the framework of our calculations based on the Ca${\mathrm{F}}_{2}$ structure in which the hydrogen occupies all of the available tetrahedral sites. Instead, indirect evidence suggests that these low-energy features are associated with partial occupation of octahedral sites.

Electronic structure of metal hydrides. I. Optical studies of Sc H 2 , Y H 2 , and Lu H 2

Abstract: We have examined the electronic structure of Sc${\mathrm{H}}_{2}$, Y${\mathrm{H}}_{2}$, and Y${\mathrm{H}}_{2}$ using optical absorptivity and thermoreflectance techniques in the photon energy range from 0.2 to 5 eV between 4.2 and 340 K. The measured quantities were used to determine the frequency-dependent dielectric functions and the dependence of the dielectric functions on temperature modulation. The results show that the low-energy properties ($h\ensuremath{ u}\ensuremath{\lesssim}1.5$ eV) are dominated by intraband absorption and a plasmon falling near 1.5-1.8 eV. Interband absorption is observed to be strong and structured above the interband onsets of \ensuremath{\sim} 1.25, \ensuremath{\sim} 1.6, and \ensuremath{\sim} 1.9 eV for Sc${\mathrm{H}}_{2}$, Y${\mathrm{H}}_{2}$, and Lu${\mathrm{H}}_{2}$, respectively. The observed interband features can be interpreted in terms of the self-consistent band calculations of Sc${\mathrm{H}}_{2}$ and Y${\mathrm{H}}_{2}$ presented in the companion paper, and experimental features can be related to specific bands in particular parts of the Brillouin zone. The systematics observed in these three trivalent metal dihydrides can be correlated well to theory. Extensive studies with samples of varying hydrogen to metal ratio ($x$) within the dihydride phase were carried out to examine the influence of hydrogen sublattice disorder on the optical properties and electronic structure. It was observed that, for $x$ approaching 2, interband features which could be related to $d$-band absorption were broadened by increasing lattice disorder, and new features in the interband absorption spectra were observed which could not be interpreted without postulating the hydrogen occupancy of significant numbers of octahedral sites. The strong $x$ dependence of the optical features emphasizes the importance of studying well-characterized samples.

Low-energy interband absorption in bcc Fe and hcp Co

Abstract: We have examined the electronic structure of bcc Fe and single-crystal hcp Co by using optical absorptivity and thermoreflectance techniques for $0.2\ensuremath{\le}h\ensuremath{ u}\ensuremath{\le}5$ eV. The optical conductivities $\ensuremath{\sigma}$ were calculated by Kramers-Kronig analyses. A prominent structure was observed in $\ensuremath{\sigma}$ for Fe at 2.37 eV and a shoulder was observed near 0.8 eV; the latter structure was the dominant feature in the thermoreflectance spectrum. These were discussed in terms of minority-spin band interband absorption and spin-flip interband transitions. The anisotropic optical conductivities of hcp Co were discussed in terms of recent energy-band calculations.

Lattice dynamics of hcp Hf

Abstract: Inelastic neutron scattering techniques have been used to study the lattice dynamics of hcp Hf. The phonon dispersion curves along the [001], [100], and [110] symmetry directions were determined at 295 and 1300 K, and a selected number of phonon frequencies were measured also at 800 K. As the temperatures decreases we observe a rather large increase in the frequencies of all but the [001] LO branch. The zone-center mode of the [001] LO branch, on the other hand, softens appreciably, and at room temperature this branch exhibits a dip at the zone center. These features of the phonon dispersion curves of Hf are similar to those of hcp Zr and Ti. The data were used to evaluate the lattice specific heat at constant pressure as a function of temperature. The calculated total specific heat, obtained by taking into account the electronic contribution, was found to agree, to within experimental uncertainties, with the results of specific-heat measurements. We find that the phonon anomalies (and their temperature dependence) in the dispersion curves of the superconducting elements of the IV column of the Periodic Table can be understood qualitatively as originating from the splitting about the Fermi level of doubly degenerate bands by the lattice distortion corresponding to the [001] LO mode. We argue that this mechanism may also be responsible for the phonon anomalies observed in other superconducting elements (Tc) and compounds (La${\mathrm{Sn}}_{3}$).

Sister-chromatid exchanges in human lymphocytes exposed during G0 to four classes of DNA-damaging chemicals

Abstract: Human lymphocytes were treated prior to mitogenic stimulation with varying concentrations of 6 cytostatic drugs representing 4 classes of DNA-damaging chemicals Afterwards the cells were washed to remove residual chemical and cultured in the presence of bromodeoxyuridine for analysis of sister-chromatid exchanges (SCEs) A dose-related increase in SCEs was observed in cells exposed during G 0 to the alkylating chemicals mitomycin C, chlorambucil, and thiotepa, while significant increases in SCEs were not noted in cultures exposed to methotrexate, cytarabine, or bleomycin These findings suggest that not all classes of clastogenic chemicals which induce SCEs in proliferative cells substituted with BUdR are capable of inducing long-lived lesions in the DNA of G 0 lymphocytes that can lead to SCE formation

NMR studies of hydrogen diffusion in β-LaNi5−yAly hydrides☆

Abstract: The complementary techniques of nuclear reaction analysis and infrared absorption were used to study the concentration profiles and chemical bonding of hydrogen in silicon nitride for different preparation and annealing conditions. Silicon nitride prepared by chemical vapor deposition from ammonia-silane mixtures is shown to have hydrogen concentrations of 8.1 and 6.5 at.% for deposition temperatures of 750 and 900‡C, respectively. Plasma deposition at 300‡C from these gases result in hydrogen concentrations of ~22 at.%. Comparison of nuclear reaction analysis and infrared absorption measurements after isothermal annealing shows that all of the hydrogen retained in the films remains bonded to either silicon or nitrogen and that hydrogen release from the material on annealing is governed by various trap energies involving at least one Si-H and two N-H traps. Reasonable estimates of the hydrogen release rates can be made from the effective diffusion coefficient obtained from measurements of the spreading of the implanted hydrogen distribution upon annealing.

Hydrogen concentration profiles and chemical bonding in silicon nitride

Abstract: The complementary techniques of nuclear reaction analysis and infrared absorption were used to study the concentration profiles and chemical bonding of hydrogen in silicon nitride for different preparation and annealing conditions. Silicon nitride prepared by chemical vapor deposition from ammonia-silane mixtures is shown to have hydrogen concentrations of 8.1 and 6.5 at.% for deposition temperatures of 750 and 900‡C, respectively. Plasma deposition at 300‡C from these gases result in hydrogen concentrations of ~22 at.%. Comparison of nuclear reaction analysis and infrared absorption measurements after isothermal annealing shows that all of the hydrogen retained in the films remains bonded to either silicon or nitrogen and that hydrogen release from the material on annealing is governed by various trap energies involving at least one Si-H and two N-H traps. Reasonable estimates of the hydrogen release rates can be made from the effective diffusion coefficient obtained from measurements of the spreading of the implanted hydrogen distribution upon annealing.

Rational Synthesis of Unidimensional Mixed Valence Solids. Structure-Oxidation State-Charge Transport Relationships in Iodinated Nickel and Palladium Bisbenzoquinonedioximates.

Abstract: : The results of the present investigation indicate that the M(bqd)2I(0.50) materials, M = Ni, Pd, are best formulated as M(bqd)2I(0.50).S materials where S represents various amounts of the aromatic solvent employed for crystallization. As deduced from resonance Raman, I-129 Mossbauer, and diffuse x-ray scattering measurements, the iodine is present as I3-, and thus the m(bqd)2I(0.50).S materials are indeed partially oxidized.

30-MJ superconducting magnetic energy storage (SMES) unit for stabilizing an electric transmission system

Abstract: Electric power systems that have major loads and generation centers separated by large distances may experience low-frequency power oscillations. This type of oscillation has occurred on the Pacific AC Intertie that connects southern California and the Pacific Northwest. A separate, almost parallel, dc-transmission line also connects these areas. The Bonneville Power Administration, which operates this transmission system, has overcome the instability by controlling the power transmitted on the dc-transmission line. A 30-MJ (8.4-kWh) superconducting magnetic energy storage unit with a 10-MW converter could also provide damping for this instability. The conceptual design of the 30-MJ coil and the cryogenic and electrical components of the system are described. The system is to operate at a maximum current of 5 kA and will modulate the AC Intertie at 0.35 Hz. Discharge will be controlled to retain a minimum stored energy of 20 MJ to limit cyclic strains in the coil and ac losses in the conductor. The conductor will be made of multistrand-copper and copper-matrix, multifilament NbTi superconducting wires on a stainless steel mandrel.

Effectiveness of Interference Filters for Reduction of Stray Light Effects in Atomic Emission Spectrometry

Abstract: Quantitative data are presented on the effectiveness of interference filters for reduction or elimination of stray light effects in optical spectrometers employed for trace atomic emission analyses Specific attention is focused on those analyte species that contribute significant stray light at wavelengths far removed from the offending radiation For simultaneous multielement determinations with a polychromator, band reflection filters are shown to provide an attractive means of eliminating stray light effects arising from the very intense Ca lines emitted in an inductively coupled plasma For the spectrometers used in the present study, a major fraction of the background shifts caused by changing concentrations of Mg arose from real background contributions rather than from stray light

Electron-energy-loss spectra of vanadium, niobium, molybdenum, and tantalum

Abstract: Electron-energy-loss spectra were obtained out to approximately 80 eV in the reflection mode from atomically clean foil samples of vanadium, niobium, molybdenum, and tantalum. Results are compared with previous ultraviolet optical work and electron-energy-loss spectroscopy (ELS) studies on these materials. Resolution of structure is improved over many previous ELS investigations by using synchronous detection techniques in determining energy locations. Origins of the various observed structures are discussed in light of previous studies, particularly ultraviolet optical work leading to the determination of the complex dielectric function. We comment on discrepancies existing in the literature about plasmon energies in these materials estimated from infrared optical measurements.

Effects of Steam Injection on the Performance of Gas Turbine Power Cycles

Abstract: The effect of injecting steam generated by exhaust gas waste heat into a gas turbine with 3060°R turbine inlet temperature has been analyzed. Two alternate steam injection cycles are compared with a combined cycle using a conventional steam bottoming cycle. A range of compression ratios (8, 12, 16, and 20) and water mass injection ratios (0 to 0.4) were analyzed to determine effect on net turbine power output per pound of air and cycle thermodynamic efficiency. A water/fuel cost tradeoff analysis is also provided. The results indicate promising performance and economic advantages of steam injected cycles relative to more conventional utility power cycles. Application to coal-fired configuration is briefly discussed.

Cerebellar Medulloblastoma. Results of a new method of radiation treatment

Abstract: Nine patients with medulloblastoma were referred to the Radiation Oncology Section at the University of Chicago from 1966 to 1976. In all patients, the tumor was situated in the posterior cranial fossa, projecting from the cerebellum into the fourth ventricle. After partial tumor resection and histological diagnosis, radiation treatment was instituted: a localized dose of 1000 rad to the posterior fossa through lateral opposing ports and a total dose of 4000-5000 rad through the "hockey-stick" port to the entire CNS. With this treatment, 9 patients yielded actuarial 3- and 5-year survival rates of 88% and 73%, respectively. Five of the patients possessed no history of neurologic or spinal growth deficits after treatment. Two patients had a slight retardation of spinal growth. The remaining patients had presented symptoms of a tumor mass in the posterior fossa for a period of over 8 months prior to treatment. They were found at craniectomy to have diffuse intracranial tumor involvement, and their survival times deteriorated rapidly. The "hockey-stick" port provided a uniform distribution of radiation exposure to the entire brain and spine. It was simple to use and posed little inconvenience to patients in the pediatric age group.

Evolution of karyotypes in Philadelphia (Ph1) chromosome-negative chronic myelogenous leukemia.

Abstract: Ten of 55 patients with chronic myelogenous leukemia (CML) diagnosed between 1972 and 1977 were found to lack the Philadelphia (Ph1) chromosome. Serial clinical, morphologic, and cytogenetic studies of patients with Ph1-negative CML showed that 30% of them had chromosomal abnormalities. Two had an extra chromosome No. 8 at the time of blast crisis, with a morphological picture of myeloblasts in the bone marrow. A third patient had a 6:14 translocation initially Abnormalities of chromosome No. 14 are frequently seen in lymphoproliferative disorders, and the bone marrow and peripheral blood contained a significant population of lymphoblasts as well as myeloblasts. The median survival for the 10 patients was 19 months. The exact nature of Ph1-negative CML is not yet clear; disease appears to be a distinct entity among the myeloproliferative disorders.