Solute–Solvent and Solute–Solute Interactions of Resorcinol in Mixed 1,4-Dioxane–Water Systems at Different Temperatures

The densities, viscosities, and ultrasonic speeds of resorcinol in 1,4-dioxane + water mixtures and in pure 1,4-dioxane have been measured at 303.15, 313.15, and 323.15 K. Apparent molar volumes (V_ϕ) and viscosity B-coefficients are obtained from these data supplemented with densities and viscosities, respectively. The limiting apparent molar volumes ( ) and experimental slopes ( ) derived from the Masson equation have been interpreted in terms of solute–solvent and solute–solute interactions, respectively. The viscosity data have been analyzed using the Jones–Dole equation, and the derived parameters B and A have also been interpreted in terms of solute–solvent and solute–solute interactions, respectively. The structure making/breaking capacities of resorcinol in the studied solvent systems have been discussed. The compressibilities obtained from the data supplemented with their ultrasonic speeds indicate the electrostriction of the solvent molecules around the ions     

Preparation of Diamond in the Graphite–M (M = Sn,Pb) Binary Systems: Synthesis and Structural Defects

Inorganic Materials - Diamond has been synthesized in the graphite–Sn and graphite–Pb systems at pressures from 8 to 9 GPa and temperatures above 1500 and 2000°C, respectively. The...     

Preparation and Characterization of Ultrafine ZrO_ Powders from Solvent Extraction of Zr(Ⅳ) with Tri-n-butyl Phosphate in Kerosene from Nitric Acid Solutions

Zr(IV) was extracted by tri-n-butyl phosphate in kerosene from concentrated nitric acid solutions and the formation of the third phase during extraction was experimentally investigated. Zirconia powders were prepared by using the loaded organic phase as the bulk solution precipitated with aqueous ammonia or NaOH solution. The powder prepared was characterized with TEM, XRD,EDAX and TG-DTA. Effects of some conditions on powder preparation were studied and it was shown that nanosized particles could be obtained from this extraction system but conditions should be carefully controlled for powder purity and particle size.     

Chemical Equilibrium and Critical Phenomena: The Solubilities of Iron(III) Oxide and Cobalt(II,III) Oxide in Isobutyric Acid + Water Near the Consolute Point

The solubilities of iron(III) oxide, formula Fe₂O₃, and cobalt(II,III) oxide, formula Co₃O₄, have been determined in the liquid mixture, isobutyric acid + water, along the critical isopleth at temperatures above the upper critical solution temperature near 299 K. When plotted in van’t Hoff form with ln s versus 1/T, the measurements of solubility, s, lie on a straight line for values of the temperature, T, in kelvin, which are sufficiently in excess of the critical solution temperature, T _c. The sign of the slope, (? ln s/?(1/T)), indicates that in the case of both oxides, the dissolution reaction is endothermic. When the temperature is within 1K of T _c, however, the slope departs from its constant value and appears to diverge toward negative infinity. The principle of critical-point universality predicts that a divergence in (? ln s/?(1/T)) is to be expected for T near T _c in those cases where the stoichiometry of the dissolution reaction involves both components of the solvent; moreover, the Gibbs–Helmholtz equation predicts that, if the heat of solution is endothermic, the sign of the divergence should be negative. Both of these predictions are confirmed by the solubilities of Fe₂O₃ and Co₃O₄ measured as a function of temperature along the critical isopleth of isobutyric acid + water.     

Structural Eurocodes Systems (China) Forum Held in Beijing——Construction Standards in China

The Structural Eurocodes System s,w hich are de-veloped by the European Com m ittee forStandardization(CEN ),have com e into trialuse in the 28 countries ofEuropean U nion (EU ),and w illlay a significantinflu-ence on the developm ent of the construction industryand on theinternationalm arketofconstruction.In orderto prom ote China’sexchange and cooper-ation w ith EU in the field ofstandardization,understandthe new est trend and developm ent of the constructionstandardsofEU and the new …     

Measurements of the Properties of Binary Mixtures of Dimethylsulphoxide (DMSO) with 1-Alkanols (C4, C6, C7) at 303.15 K

This paper presents experimental data for densities, ρ, ultrasonic velocities, u, and refractive indices, n, of pure dimethylsulphoxide (DMSO), 1-butanol, 1-hexanol, 1-heptanol, and their binary mixtures, with DMSO as a common component, over the whole composition range at 303.15 K. The molar refraction, R_m, molecular association, M_A, excess molar volume, V^E, and deviation in isentropic compressibility, ΔK_s, were calculated from the experimental data. The apparent molar volume, V_ϕ,2, and apparent molar isentropic compressibility, K_ϕ,2, of alkanols in DMSO were also calculated. The values of V_ϕ,2 and K_ϕ,2 were used to estimate the partial molar volume, , and partial molar isentropic compressibility, , of alkanols in DMSO at infinite dilution. The changes in these parameters with composition and the size of the alkyl chain length in the alkanol molecule are discussed with reference to the nature of interactions between component molecules. Excess molar volumes have also been estimated from measurements of refractive indices     

A Simplified Regular Solution Model for Solubility of Nonmetal (2) in Metal(1)-Metal(3) Alloy Systems

A simplifled regular solution model for the solubility of nonmetallic element (2) in metal(1)-metal(3) alloy system has been derived and applied to the Fe-C-j, Ni-C-j and Fe-N-j (j denotes a metal) systems with satisfaction. The exchange energies of concerned systems are evaluated     

Life History Responses and Feeding Behavior of Microcrustacea in Altered Gravity – Applicability in Bioregenerative Life Support Systems (BLSS)

Manned space missions, as for example to the planet Mars, are a current objective in space exploration. During such long-lasting missions, aquatic bioregenerative life support systems (BLSS) could facilitate independence of resupply from Earth by regenerating the atmosphere, purifying water, producing food and processing waste. In such BLSS, microcrustaceans could, according to their natural role in aquatic ecosystems, link oxygen liberating, autotrophic algae and higher trophic levels, such as fish. However, organisms employed in BLSS will be exposed to high acceleration (hyper- g) during launch of spacecrafts as well as to microgravity (μg) during space travel. It is thus essential that these organisms survive, perform and reproduce under altered gravity conditions. In this study we present the first data in this regard for the microcrustaceas Daphnia magna and Heterocypris incongruens. We found that after hyper-g exposure (centrifugation) approximately one third of the D. magna population died within one week (generally indicating that possible belated effects have to be considered when conducting and interpreting experiments during which hyper-g occurs). However, suchlike and even higher losses could be countervailed by the surviving daphnids’ unaltered high reproductive capacity. Furthermore, we can show that foraging and feeding behavior of D. magna (drop tower) and H. incongruens (parabolic flights) are rarely altered in μg. Our results thus indicate that both species are suitable candidates for BLSS utilized in space.     

Vapor–Liquid Equilibria of CFC Alternative Refrigerant Mixtures: Trifluoromethane (HFC-23)+Difluoromethane (HFC-32), Trifluoromethane (HFC-23)+Pentafluoroethane (HFC-125), and Pentafluoroethane (HFC-125)+1,1-Difluoroethane (HFC-152a)

Isothermal vapor–liquid equilibria for three binary mixtures of CFC alternative refrigerants were determined in an equilibrium apparatus in which both phases were continuously recirculated. The pressures and vapor and liquid compositions were measured for the binary systems trifluoromethane (HFC-23)+difluoromethane (HFC-32) and trifluoromethane (HFC-23)+pentafluoroethane (HFC-125) at 283.15 and 293.15 K and pentafluoroethane (HFC-125)+1,1-difluoroethane (HFC-152a) at 293.15 K. The experimental data were correlated with the Peng–Robinson–Stryjek–Vera equation of state using the Huron–Vidal original mixing rule. Calculated results with this equation showed good agreement with the experimental data.     

Cation–Cation Interaction in Complexes of Np(V) Benzoate and Salicylate with N-Containing Molecular Ligands

Radiochemistry - The hydrothermal method was used to obtain two new compounds of Np(V): benzoate [(NpO2)3(py) (C7H5O2)3(H2O)2] (1) and salicylate [(NpO2)(phen)(HOC7H4O2)] (2), where py = pyridine...     

Crystal Structure of (Ti,Mo)12P7and Refined Phase Equilibria in the Ti–Mo–P System

A new ternary compound of composition Ti_3.8Mo_8.2P_7.0 was identified, and its structure was determined by single-crystal x-ray diffraction: sp. gr. P6¯, a= 1.67821(6) nm, c= 0.33196(2) nm; R _F = 0.073 and R _w = 0.078 for 1359 independent reflections with F _hkl > 4(F _hkl). The phase equilibria in the Ti–Mo–P system were refined in the region 0–25 mol % Ti and 33–40 mol % P.     

New negative temperature coefficient thermistor ceramics in (Y2O3 + CeO2)–LaCr0.5Mn0.5O3 composite system

A new series of composite, negative temperature coefficient (NTC) ceramics based on the (aY₂O₃ + bCeO₂)?0.4LaCr_0.5Mn_0.5O₃ (a + b = 0.6) were carefully prepared and related electrical properties were investigated. All the NTC thermistors showed a linear relationship between the natural logarithm of the resistance and the reciprocal of the absolute temperature, indicative of NTC characteristics. The obtained B _25/85 constants were in range of 2,100–2,700 K. The magnitude order of the resistivity at 25 °C was of 10³–10⁹ Ωcm and activation energies varied from 0.185 to 0.231 eV. The aging coefficient of the NTC thermistors with CeO₂ was less than 2 % for the time period of 900 h, suggesting that NTC thermistors with CeO₂ possessed a better electrical stability in comparison with CeO₂-free thermistors.     

Phase Relations in the Systems M–Mn–P (M = Cr, Mo, W, Re)

The 1070-K phase relations in the M–Mn–P (M = Cr, Mo, W; 67 at. % P) and Re–Mn–P (50 at. % P) systems were studied by x-ray diffraction. The existence of the known phosphides Mo₄Mn₆P₅ and (Mn,W)₁₂P₇ was confirmed, and a new phase with the general formula (Mn,Mo)₁₂P₇ and stoichiometry range Mo_4.6–1.8Mn_7.4–10.2P₇ was identified. Its structure was determined by powder diffraction profile analysis (R = 0.074): Cr₁₂P₇ structure type, sp. gr. P6, a = 0.94929(8) nm and c = 0.33565(3) nm for Mn_7.4Mo_4.6P₇. The Mo and Mn atoms in the structure of this phase were shown to occupy all positions at random. In addition to the known solid solutions (Cr,Mn)₃P (Ni₃P structure type), (Cr,Mn)₁₂P₇ (Cr₁₂P₇), (Cr,Mn)P, and (Mn,Mo)P (MnP), we revealed new solid-solution series: (Cr,Mn)₂P (Cr₂P), (Mn,Cr)₂P (Fe₂P), (Mn,Mo)₃P (Ti₃P), (Mo,Mn)₃P (-V₃S), (Mo,Mn)P (WC), (W,Mn)P (MnP), (Mo,Mn)P₂, and (W,Mn)P₂ (MoP₂). The Re–Mn–P system was found to contain neither ternary phosphides nor solid solutions.     

Spectrophotometric Determination of the Ionization Constant of Dimethylpicric Acid (2,4,6-Trinitro-3,5-xylenol) in Water at 25 °C

The ionization constant of dimethylpicric acid (2,4,6-trinitro-3,5-xylenol) in water at 25 °C has been determined by a spectrophotometric method. The pK value 1.38 (K ≈0.042) was obtained. Potentiometric titrations, although less precise, yielded a pK value of the same magnitude.     

Adsorption and Diffusion Behavior of Cl~- on Sputtering Fe–20Cr Nanocrystalline Thin Film in Acid Solution(pH = 2)

The adsorption and diffusion behavior of Cl~- on sputtering Fe-20 Cr nanocrystalline(NC) thin film compared with corresponding coarse crystalline(CC) alloy has been studied in HCl + NaCl solution(pH = 2,[Cl~-]=0.1 mol/L) by electrochemical techniques,X-ray photoelectron spectroscopy(XPS) and the firstprinciples calculations.The XPS results show that adsorption and diffusion of Cl~- in the passive film has been inhibited on NC thin film.Ultra-violet photoelectron spectroscopy(UPS) results show that the work function Φ_s of NC thin film(4.7 eV) is higher than that of CC alloy(4.5 eV).The theoretical calculations and valence electron structure analysis were used to understand the effect of nanocrystallization in this work.     

Solvatochromic Study of Poly(vinyl chloride) Plasticizers and Their Solutions in Chloroform: Application to Phenobarbital Partitioning and Molecular Recognition of Phenobarbital

The possibility now exists, with the availability of several families of artificial molecular receptors, to create selective extraction media. More selective extractions will lead to cleaner chromatograms, with lower detection limits and perhaps higher accuracy for trace organic analysis by chromatography. Furthermore, laboratories will be expected to minimize the use of volatile organic solvents. Consequently, nonvolatile, reusable solvents will be the basis for extractions. In addition, as artificial molecular receptors become more widely available, these solvents will be used to support molecular recognition. We have focused on plasticizers of poly(vinyl chloride) as examples of these solvents. We have determined solvatochromic parameters of several plasticizers and their solutions in chloroform. These parameters, along with cohesive energy density and solvent molar volume, were used to derive linear free energy relationships for the free energies of phenobarbital partitioning between solvent and aqueous solution, receptor solubility, formation of a complex with a barbiturate receptor [1,3-bis[[[6-(1-butyrylamino)pyrid-2-yl]amino]carbonyl]benzene (2)], and the transfer of the complex (artificial receptor and phenobarbital) from chloroform to other solvents. Solvent dipolarity/polarizability and hydrogen bond basicity, but not acidity, support complex dissociation. Solvents with large molar volumes dissolve the polar solutes, phenobarbital, receptor, and complex more poorly than solvents with lower molar volume, but there is no influence of molar volume on complex formation.     

Hydrothermal-polyol route to synthesis of β-Ni(OH)2 and NiO in mixed solvents of 1,4-butanediol and water

The β-Ni(OH)₂ with flower-like morphology assembled from nanosheets has been successfully synthesized by a hydrothermal-polyol method from Ni(CH₃COO)₂·4H₂O in mixed solvents of 1,4-butanediol and water at 200 °C for 24 h. The NiO with similar morphology was obtained by a simple thermal decomposition of the precursor (β-Ni(OH)₂) at 400 °C for 3 h in air. The products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), thermogravimetric analysis (TG) and differential scanning calorimetric analysis (DSC). We expect that this hydrothermal-polyol method may be extended to the preparation of nanostructures of other kinds of metal oxides.     

Tl-NMR Study on High–Tc Oxides TlM2CaCu2O7–δ(M=Ba, Sr) : Spin-Gap in Underdoped and Overdoped Systems

The Spin–lattice relaxation rate and the Knight shift have been measured for Tl–based cuprates TlBa ₂ CaCu ₂ O ₇₊ (TB1212) and TlSr ₂ Y _l–x Ca _x Cu ₂ O ₇₊ (TS1212). In the underdoped sample of TS1212 with Tc=34K. (T ₁ ) ^–1 showed a gap–like behavior from the temperature T _SG=120K. As for the slightly overdoped sample of TB1212 with T _c =80K, both the Knight shift and (T ₁ ) ^–1 showed a significant decrease from 160K, suggesting the existing of the spin-gap not only around q(, ) but also q0.     

Phase Relations in the Systems Ln1 – x Ba x CoO3 – δ(0 < x ≤ 0.66; Ln = Nd, Sm)

Data are presented on the structural and magnetic properties of Ln_{1 – x} Ba _x CoO_{3 –} (Ln = Nd, Sm; 0 < x 0.66) samples slowly cooled in air after synthesis. The composition stability limits of the intermediate phases Ln_{1 – y} Ba_{1 + y} Co₂O_{5 +} and solid solutions are determined. The magnetic phase diagram of the Nd_{1 – x} Ba _x CoO_{3 –} system is constructed.