Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
A transient metastable rotator phase occurring on crystallization of hexadecane into its triclinic phase from the supercooled melt was directly observed with time-resolved synchrotron x-ray scattering. In this system, the limit of supercooling (the crystallization temperature) is determined by the thermodynamic stabil…
Mesoporous aluminosilicate in the hexagonal phase (MCM-41) has been synthesized from fused fly ash solutions and cationic cetyltrimethylammonium bromide (CTAB) surfactants. We provide direct evidence that an MCM-41 aluminosilicate with a homogeneous chemical composition of Si/Al = 13.4 can be prepared with cationic su…
We examine the effective diffusion coefficient of composites containing randomly placed, impermeable, oriented disks of high aspect ratio. We extend previous work by providing a quantitative framework in which to examine disorder and polydispersity effects, as well as treating explicitly the crossover from the dilute…
A synthetic concept of preparing dense polymer brushes on planar surfaces is described, in which a self-assembled monolayer (SAM) of biphenyllithium moieties on gold substrates is used to initiate anionic polymerization of styrene. The thickness of the resulting dry polystyrene brush, as estimated by ellipsometry and…
Optical surfaces coated with a thin layer to improve light transmission are ubiquitous in everyday optical applications as well as in industrial and scientific instruments. Discovered first in 1817 by Fraunhofer, the coating of lenses became standard practice in the 1930s. In spite of intensive research, broad-band an…
The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-asse…
CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accountin…
The morphology of chiral ( R )- and ( S )-poly(epichlorohydrin) (PECH) single crystals grown from solution was studied to obtain insight into the mechanism by which the chiral character of the main chain can be transmitted to higher organizational levels, such as the lamellar twisting orientation in banded spherulites…
By employing the ethylenediamine extraction reaction of a pentanary alloy with the nominal composition of K4AuSn2Sb2Te11, the discrete ternary Zintl anion [AuSn2Te6]3- was isolated. The structure of the [AuSn2Te6]3- anion is composed of a dimeric [Sn2Te6]4- anion and a [AuTe2] unit. A highly strained [AuSn2Te6]3- anio…
Defluorination of a film of highly oriented poly(tetrafluoroethylene) (PTFE) was carried out by the action of lithium and sodium amalgams. The reaction yields a composite product containing carbon with the equivalent amount of alkali metal fluoride. This material was studied by X-ray photoelectron spectroscopy, Raman…
A new dendrimer ( 1 ), which contains phenol groups in the exterior for solubilization in aqueous alkaline solution and calix[4]resorcinarene in the interior to increase the molecular weight and number of the phenol group even in the lower generation, was designed as new negative-working, alkaline-developable photores…
The spontaneous precipitation of calcium sulfate in supersaturated solutions over the temperature range between 25.0 and 80.0 °C was investigated by monitoring the solution specific conductivity during desupersaturation. From measurements of the induction times preceding the onset of precipitation the surface energy o…
The formation of silica−surfactant mesostructures has been studied under various acidic conditions using tetraethyl orthosilicate and hexadecyltriethylammonium bromide. The synthesis conditions have been optimized in order to obtain the cubic ( Pm 3 n ) mesoporous molecular sieve designated as SBA-1 of high quality. T…
Introduction In the previous chapter we discussed the econometric problems that might occur when we run a regression with different orders of integrated variables. To avoid this problem, the first thing we have to do is to identify the correct order of the integration of each variable. In the context of ARIMA modeling…
Water-insoluble poly(ethylene oxide - b -ε-caprolactone) (PEO - b -PCL) diblock copolymer ( M w = 1.71 × 10 4 g/mol and W PEO = 20%) was successfully micronized into small polymeric core−shell nanoparticles (micelles) stable in water via a microphase inversion method. Such formed PEO - b -PCL nanoparticles are biodegr…
We have performed ab-initio calculations of exchange couplings in the layered vanadates CaV2O5, MgV2O5, CaV3O7 and CaV4O9. The uniform susceptibility of the Heisenberg model with these exchange couplings is then calculated by quantum Monte Carlo method; it agrees well with the experimental measurements. Based on our r…
The role of the intrinsic surface state ($n=0$) in the decay of the first image state ($n=1$) at the (111) surface of copper is investigated. Inelastic linewidths are evaluated from the knowledge of the imaginary part of the electron self-energy, which we compute, within the GW approximation of many-body theory, by go…
Theoretical aspects of polymers in mixed solvents are considered using the Edwards Hamiltonian formalism. Thermodynamic and structural properties are investigated and some predictions are made when the mixed solvent approaches criticality. Both the single and the many chain problems are examined. When the pure mixed s…
The process of controlled laser sintering for powdered SHS compositions with the bases Ni-Ti and Ni-Al was realized. The optimal parameters of laser effect, under which the reaction of SHS proceeds in controlled regime, were determined. The phase composition of the sintered structure was revealed by the x-ray phase an…
The structures and energies of the binary dititanium dicarbide, Ti 2 C 2, in the lowest singlet, triplet, and quintet states have been investigated by density functional theory using the hybrid B3LYP functionals. Geometries and frequencies for a number of isomeric structures are presented at the B3LYP level. A rhombic…