Housing reform in a marketised socialist economy: The case of shanghai

Abstract

Marketisation and privatization reforms implemented in Shanghai since 1980 have facilitated housing construction and the improvement of housing conditions. The multiplication of construction capital would have been impossible without an effective implementation of the consumption reforms and general improvements in the economy.     

Two-stage thermally induced stable colloidal assemblies from PAAc/PNIPAAm/mPEG graft copolymer in water

A facile approach of forming stable polymeric complexes by the two-stage phase transition of the graft copolymer comprising poly(acrylic acid) (PAAc) as the backbone and poly(N-isopropylacrylamide) (PNIPAAm) and monomethoxy poly(ethylene glycol) (mPEG) as the grafts in water was illustrated. Rather loose and hydrated polymeric aggregates with a characteristic hydrophobic multicore structure, achieved by the first-stage thermally induced phase transition of PNIPAAm grafts, underwent the core structure rearrangement (including multicore fragmentation and fusion) upon the second-stage dehydration of mPEG grafts at 90 °C. This was followed by hydrogen-bond pairings of mPEG and PNIPAAm chain segments with unionized AAc residues acting as an effective protective shell against potential hydration of the hydrophobic inner cores during the annealing process. The polymer complexes thus obtained show surprisingly enhanced hydrophobicity of inner cores at 25 °C in water and excellent stability of the morphological structure in response to the temperature disturbance.     

Film instability induced evolution of hierarchical structures in annealed ultrathin films of an asymmetric block copolymer on polar substrates

With an atomic-force microscope and a grazing-incidence small-angle X-ray scattering we studied ex situ the evolution of hierarchical structures in isothermally annealed ultrathin films of asymmetric polystyrene-block-poly(methyl methacrylate) P(S-b-MMA) that dewetted on polar substrates via a mechanism involving nucleation and growth. Film instability causes the surface to acquire an undulating thickness through incommensurability, producing not only the relief structures on a micrometer scale but also mesophase-separated domains on a nanometer scale. The dewetted morphologies strongly influence the ordering behavior of the nanoscale domains. The noncylindrical nanostructures become stable at the curved edges of the relief microstructures in the destabilized P(S-b-MMA) films, for which a preferential wetting of the PS block with the free surface is prohibited. Additionally, the shape of relief structures as result of film instability correlates with the formation of mesophase-separated nanodomains. At early stages of film instability, the formation of parallel-oriented PMMA cylindrical nanodomains increases the deformation energy and it further persists to force the shape of relief structures between irregular holes to have a facet-wedge shape. However, those relief structures are expected to be not at equilibrium. At high temperatures, the relief structures between irregular holes progressively developed to form hemispherical-cap drops accompanied by a transformation of cylindrical into noncylindrical nanodomains at curved surfaces.     

Flexible Transparent ZnO:Al/ZnO/CuAlO x :Ca Heterojunction Diodes on Polyethylene Terephthalate Substrates

Transparent flexible n ⁺-ZnO:Al (100 nm)/n-ZnO (40 nm)/p-CuAlO _x :Ca (100 nm, 200 nm, 300 nm) diodes were fabricated on polyethylene terephthalate substrates at room temperature using a sputtering technique. No additional heat treatment was performed on the fabricated devices. Increase of the diode layer thickness reduced the on-current and leakage-current levels simultaneously, which led the rectification ratio to first increase and then decrease as the p-layer thickness increased. The ultraviolet (UV) response of the diode was also investigated under irradiation at 365 nm. The n ⁺-ZnO:Al (100 nm)/n-ZnO (40 nm)/p-CuAlO _x :Ca (200 nm) diode exhibited photocurrent/leakage current ratio of 1.03 × 10³ and responsivity of 0.64 A/W at reverse bias of ?6 V when measured in flat status. The corresponding photocurrent/leakage current ratio and responsivity were 7.99 × 10² and 0.65 A/W, respectively, for an outwardly bent diode with 5.5 cm radius of curvature. The increases of current levels under bending are attributed to the decreases of series resistance for the diode under tensile strain.     

Molecular structure and transport dynamics in Nafion and sulfonated poly(ether ether ketone ketone) membranes

An atomistic simulation technique is performed to investigate the molecular structure and transport dynamics inside a hydrated Nafion membrane and a hydrated sulfonated poly(ether ether ketone ketone) (SPEEKK) membrane. The simulation system consists of the representative fragments of the polymer electrolytes, hydronium ions and solvent molecules, such as water plus methanol molecules. Simulation results show that the hydrated SPEEKK has less phase separation among hydrophobic and hydrophilic regions in comparison with the Nafion. Those water channels formed in the SPEEKK are much narrower compared to those in the Nafion. These characteristics lead to a lower mobility of hydronium ions and water molecules and hence relatively lower diffusion coefficient of methanol in the SPEEKK. It results in the reduction of the methanol permeation problem in direct methanol fuel cells.     

Mixing and chemical reaction in an initially non-uniform temperature field

The development of the velocity, temperature and the concentration profiles in the vicinity of the trailing edge is investigated under the boundary layer approximation for an arbitrary initial temperature profile and an arbitrary value of the parameter B for the chemical kinetics.

A series solution is constructed in terms of a system of “universal functions”, from which the initial development of an arbitrary initial temperature profile can be calculated with or without chemical reaction. The first three terms in the series for the temperature have been tabulated previously and are presented here in a diagram.

In the case of no chemical reaction, the analytical results for a given initial temperature distribution predict that the temperature gradient normal to the dividing stream line tends to increase for a limited distance in the downstream direction. This may not be anticipated from the consideration of thermal diffusion alone. Experimental results confirm this qualitative trend. With the three terms in the series solution for the temperature, the agreement between the analytical and the experimental results appears also quite satisfactory.

The analytical results will enable us to calculate the development of the temperature field with chemical reaction. There are as yet no experimental data for comparison.     

Development and characterization of genetic mapping resources for the turkey (Meleagris gallopavo)

The development and partial characterization of turkey genomic libraries enriched for TG, GAT, and CCT simple sequence repeats (SSR) are described. The primary library, established using conventional methods, was enriched for each of the three SSR by single-primer polymerase chain reaction (PCR). The three enriched libraries were screened by standard hybridization and washing protocols under moderate to high stringency conditions. The utility of a fraction of the markers was evaluated based on the polymorphism of PCR-amplified products in a backcross reference DNA panel. The panel consisted of genomic DNA samples from three backcrossed families developed from a cross of a wild male turkey to three inbred Orlopp line C females. A total of 181 sequences from positive clones have been characterized and deposited in GenBank. About 60% of the 60 primer pairs designed from SSR-containing sequences detected polymorphism in the reference DNA panel. The turkey genomic DNA reference panel, the enriched libraries, and the markers described here provide an opportunity to begin to characterize the turkey genome and to develop a useful public genetic map for this economically important species.