Effect of crystallization and liquid–liquid phase separation on phase‐separation kinetics in poly(ethylene‐co‐vinyl alcohol)/glycerol solution

Liquid–liquid thermally induced phase separation of the polymer‐diluent system of poly(ethylene‐co‐vinyl alcohol) (EVOH)‐glycerol was examined under light scattering. For EVOH with an ethylene content of 38 mol % (EVOH38), maxima of the scattered light intensity were observed that indicated that phase separation occurred by the spinodal decomposition (SD). The growth of the structures formed by the general liquid–liquid phase separation obeyed a power‐law scaling relationship in SD. For EVOH with an ethylene content of 32 mol % (EVOH32), the liquid–liquid phase separation resulted from the polymer crystallization. In this case, the structure growth showed the characteristic behavior in which the crystalline particles were initially formed, and then the droplets formed by the liquid–liquid phase separation induced by the crystallization grew rapidly. Furthermore, the growth of the droplet by the phase separation was followed by an optical microscope measurement at a constant cooling rate. The phase‐separated structure formed after the crystallization can grow faster than that formed by the normal liquid–liquid phase separation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 194–201, 2003     

Calculation of entropy from data of motion

We discuss the question of determining the entropy given the phase space trajectory which describes the detailed history of a many-body system over a period of observation. Our viewpoint is that the determination of entropy, as well as all other thermodynamic properties, should require no concepts or information other than those given and defined by the trajectory. The counting of coincidence (or repetition) of states along the trajectory is presented as a way to determine entropy given the trajectory. An illustrative program based on the kinetic Ising model is described in detail.     

Experimental determination of the total integrated intensity of various doublets of Cs absorption series under various pressures of foreign gases

The total integrated intensities of both doublet components and all associated satellites of the first nine members of the principal series of cesium in the presence of argon, the corresponding data for the first four members in the presence of helium, and those for the first two members in the presence of xenon were measured. Results indicate an exponential decrease in the intensity vs the relative density of rare gases. Simultaneous measurements of more than one doublet vs relative density show that the decrease in the total integrated intensities is not due to vapor pressure effects.     

Indium‐promoted Conversion of Allylic Bromide to Alcohol Moiety and Synthesis of Pipermethystine Skeletons

Dihydropyridone bromide ( 2 ) was converted to the corresponding alcohol ( 1 ) by reaction with indium in air or with indium followed by treatment with a sulfonyloxaziridine. The alcohol ( 1 ) was transformed in four steps to a phenylsulfone‐substituted pipermethystine derivative ( 10 ). Reductive cleavage of the phenylsulfone did not yield the pipermethystine natural product. Several new pyridone derivatives were synthesized.     

Dye-sensitized solar cells with 3D flower-like α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-decorated reduced graphenes oxide as photoanodes

For the first time, we report a one-step fabrication of an environment-friendly approach to synthesize flower-like α-Fe₂O₃ hierarchical nanoparticles (NPs)/reduced graphene oxide (RGO) hybrids by combining the graphene oxide (GO) with the growth of α-Fe₂O₃ NPs. The GO sheet which possesses the functional group, such as hydroxyl (–OH) and carbonyl groups (–OOH), can be easily incorporated with the petal of the flower-like α-Fe₂O₃ in ethanol and water solution through a solvothermal process, during which GO is reduced to RGO without the addition of any strong reducing agent or requiring any post-high-temperature annealing process. The as-prepared samples are loose and porous with flower-like structure, and the RGO hybrids were wrapped up uniformly on the sheet of α-Fe₂O₃ NPs. To demonstrate the potential applications, we have fabricated dye-sensitized solar cells (DSSCs) from the as-synthesized hierarchical flower-like α-Fe₂O₃/RGO and investigated it for the photoanode of DSSCs. Results show that the hierarchical α-Fe₂O₃/RGO solar cell exhibits improved performances in comparison with the free α-Fe₂O₃ NPs. The enhancement of photovoltaic properties is attributed to the unique porous nature and good conductivity which allow more efficient diffusion of I^? ions and facilitate the transfer of electron in the network.     

Polyethylene glycol （PEG） as a benign solvent for Knoevenagel condensation

The Knoevenagel condensation of aromatic aldehydes with active methylene compound proceeded efficiently in polyethylene glycol at room temperature with L-proline as catalyst. The yield is high and the products had E-isomer dominantly. Polyethylene glycol containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity.     

In situ growth of LiMn2O4 on graphene oxide for efficient lithium extraction by capacitive deionization

Journal of Solid State Electrochemistry - Selective extraction of lithium from brines has attracted significant interests with the rapid development of lithium battery industry. LiMn2O4 (LMO) is a...     

Copper-Catalyzed Enantioselective and Regiodivergent Allylation of Ketones with Allenylsilanes

We report herein a regiodivergent and enantioselective allyl addition to ketones with allenylsilanes through copper catalysis. With the combination of CuOAc, a Josiphos-type bidentate phosphine ligand and PhSiH₃, allyl addition to a variety of ketones furnishes branched products in excellent enantioselectivities. The regioselectivity is completely reversed by employing the P-stereogenic ligand BenzP*, affording the linear products with excellent enantioselectivities and good Z-selectivities. The linear Z-product could be converted to E-product via a catalytic geometric isomerization of the Z-alkene group. The silyl group in the products could provide a handle for downstream elaboration.     

Stellar structure of magnetars

Magnetars are strong magnetized neutron stars which could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of magnetic fields on the structure of isolated magnetars. The stellar structure together with the magnetic field configuration can be obtained at the same time within a self-consistent procedure. The magnetar mass and radius are found to be weakly enhanced by the strong magnetic fields. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.