Empirical Analysis on the International Competitiveness Of Shannxi Agricultural Product

On the foundation of reviewing the trade status of Shannxi agricultural product, adopting Trade Competitive Index, Revealed Comparative Advantage Index and Competitive Advantage Index, this paper calculates and evaluates the international competitiveness of Shannxi agricultural product from 1997 to 2004. It is found that from TC and CA indexes, Shannxi agriculture product is in an advantage position of international competition, while from the RCA index, it doesn’t have a very strong international advantage. In actual application, according to the trade situation of Shannxi agriculture product, we should consider synthetically the calculation results of these three indexes and develop the competitive advantage on the basis of comparative advantage. The conclusion supplies actual mentalities for promoting the international competitiveness of Shannxi agricultural product. Key words: Empirical analysis, International competitiveness, Shannxi agricultural product Résumé: Sur la base de la rétrospection du statut commercial du produit agricole du Shannxi et en adoptant l’Index compétitif du commerce, l’Index de l’avantage comparatif révélé et l’Index de l’avantage compétitif, cet essai calcule et évalue la compétitivité internaionale du produit agricole du Shannxi de 1997 à 2004. On trouve que, selon le premier et le troisième indexs, le produit agricole du Shannxi occupe une position avantageuse dans la compétition internationale, alors que d’après le deuxième index, il ne possède pas un avantage international très solide. Dans l’application actuelle, conformément à la situation du commerce du produit agricole du Shannxi, on doit considérer synthétiquement les résultats de calculation des trois index et développer l’avantage compétitif sur la base de l’avantage comparatif. La conclusion justifie les mentalités actuelles qui insistent à promouvoir la compétitivité internationale du produit agricole du Shannxi. Mots-Clés: analyse empirique, compétitivité internationale, produit agricole du Shannx

Structure and permeation of organic-inorganic hybrid membranes composed of poly(vinyl alcohol) and polysilisesquioxane

Organic-inorganic hybrid membranes with high separation performance were prepared by the incorporation of polysilisesquioxane (PSS) into a poly(vinyl alcohol) (PVA) matrix in order to solve the trade-off relationship between the selectivity and permeability of PVA membranes. The incorporation of the PSS resulted in a change in the physical and chemical structure of the hybrid membranes. The crystalline region in the hybrid membranes decreased with increasing PSS content. The hydrophilicity of the hybrid membranes increased when the PSS content is below 3 wt%, and then decreased. Silica particles formed on the surface and in the interior of the hybrid membranes due to the PSS conglomeration, and the surface roughness of the hybrid membranes increased linearly with increasing PSS content. The trade-off between permeability and selectivity was successfully solved using the hybrid membranes in pervaporation dehydration of tetrahydrofuran. The permselectivity and flux of the hybrid membranes increased simultaneously when the PSS content was below 2 wt%, whereas the permselectivity decreased when the PSS content was above 2 wt%. The hybrid membrane containing 2 wt% PSS had the highest separation factor of 1810.National Nature Science Foundation of China [50573063]; Program for New Century Excellent Talents in University ; Doctoral Program of Higher Education [2005038401

Analyzing solubility and diffusion of solvents in novel hybrid materials of poly(vinyl alcohol)/gamma-aminopropyltriethoxysilane by inverse gas chromatography

Novel hybrid materials were prepared through sol-gel reaction of poly(vinyl alcohol) (PVA) and c-aminopropyltriethoxysilane (APTEOS). Solubility and diffusion behavior of a series of solvents in the PVA/APTEOS hybrid materials were studied by inverse gas chromatography (IGC) fitted with a packed column. Solubility thermodynamics parameters at infinite dilution, such as the activity coefficient Omega(infinity)(1) and the solubility coefficient S of solvents in the hybrid materials, the partial molar excess free energy of mixture Delta G(m), and the Flory-Huggins interaction parameter chi(infinity)(12) were determined. The infinite dilution diffusion coefficients D-infinity of the solvents in the hybrid materials were also calculated. Effects of APTEOS content in the stationary phase and the column temperature on the solubility and diffusion of solvents in the hybrid materials were investigated. The hybrid material containing 5.0 wt% APTEOS has the strongest interaction with water, the largest S and D-infinity for water, and the hybrid material has a promising application in membrane separation, such as pervaporation dehydration of alcohol solution. The solubility parameter delta(2) of the hybrid materials was estimated, and it decreased with increasing APTEOS content. The dependence of D-infinity on temperature was in good agreement with the Arrhenius equation

Colloidosomes from poly(N-vinyl-2-pyrrolidone)-coated poly(N-isopropylacrylamide-co-acrylic acid) microgels via UV crosslinking

National Nature Science Foundation of China [21376194, 21107089, 21076170]; Nature Science Foundation of Fujian Province of China [21107089]; Priority Areas of Development in Doctoral Program of Higher Education [20130121130006]We first report the synthesis of colloidosomes via UV crosslinking of PVP-coated microgels. The photo-crosslinkable poly(N-vinyl-2-pyrrolidone) (PVP) was coated as a layer on the surface of poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)) microgels at pH = 3.5. A toluene-in-water Mickering emulsion was further fabricated based on the resulting PVP/P(NIPAM-co-AAc) microgels and then exposed to UV irradiation leading to the formation of colloidosomes. Since only the microgels on the surface of emulsion droplets could be crosslinked by UV irradiation, the yield and the mean size of the colloidosomes can be controlled by the amount of toluene used in the preparation. The proposed method presents a new platform to fabricate colloidosomes since photo-responsive comonomers or/and chemical crosslinkers are not essential in the system. The colloidosomes can be used as a vehicle for both hydrophilic and hydrophobic dyes. The release of the encapsulated dyes can be controlled by temperature

Colloidosomes from poly(N-vinyl-2-pyrrolidone)-coated poly(N- isopropylacrylamide-co-acrylic acid) microgels via UV crosslinking

We first report the synthesis of colloidosomes via UV crosslinking of PVP-coated microgels. The photo-crosslinkable poly(N-vinyl-2-pyrrolidone) (PVP) was coated as a layer on the surface of poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)) microgels at pH = 3.5. A toluene-in-water Mickering emulsion was further fabricated based on the resulting PVP/P(NIPAM-co-AAc) microgels and then exposed to UV irradiation leading to the formation of colloidosomes. Since only the microgels on the surface of emulsion droplets could be crosslinked by UV irradiation, the yield and the mean size of the colloidosomes can be controlled by the amount of toluene used in the preparation. The proposed method presents a new platform to fabricate colloidosomes since photo-responsive comonomers or/and chemical crosslinkers are not essential in the system. The colloidosomes can be used as a vehicle for both hydrophilic and hydrophobic dyes. The release of the encapsulated dyes can be controlled by temperature. ? 2014 The Royal Society of Chemistry

UV-crosslinked chitosan/polyvinylpyrrolidone blended membranes for pervaporation

National Nature Science Foundation of China [20976145, 21076170]; Nature Science Foundation of Fujian Province of China [2009J01040]; research fund for the Doctoral Program of Higher Education [20090121110031]; Fundamental Research Funds for the Central Universities [2012121029]Chitosan is an important biomacromolecule and polyvinylpyrrolidone (PVP) is a biocompatible synthetic polymer. The crosslinked chitosan/PVP blended membranes were prepared via UV irradiation. The as-prepared membranes have a highly crosslinked chitosan/PVP network structure originated from self-crosslinking of PVP and branching of chitosan onto PVP chains during UV irradiation. UV-Crosslinking significantly enhanced the mechanical strength and thermal stability of the blended membranes. Their highest tensile strength is twice as much as that of the pristine chitosan membrane. Maintaining the same swelling degree of the pristine chitosan membrane, the blended membranes have high sorption selectivity towards methanol and water. The as-prepared membranes exhibit an excellent performance in pervaporation separation of methanol/ethylene glycol and water/ethanol and show great potential as new biomedical materials and in the removal of alcohol and water from organics

Ultrathin self-assembled anionic polymer membranes for superfast size-selective separation

National Nature Science Foundation of China [21076170, 21376194, 21306155]; research fund for the Doctoral Program of Higher Education [20120121120013]; Fundamental Research Funds for the Central Universities [2012121029]Nanoporous membranes with superior separation performance have become more crucial with increasing concerns in functional nanomaterials. Here novel ultrahigh permeable nanoporous membranes have been fabricated on macroporous supports by self-assembly of anionic polymer on copper hydroxide nanostrand templates in organic solution. This facile approach has a great potential for the fabrication of ultrathin anionic polymer membranes as a general method. The as-fabricated self-assembled membranes have a mean pore size of 5-12 nm and an adjustable thickness as low as 85 nm. They allow superfast permeation of water, and exhibit excellent size-selective separation properties and good fouling resistance for negatively-charged solutes during filtration. The 85 nm thick membrane has an ultrahigh water flux (3306 l m(-2) h(-1) bar(-1)) that is an order of magnitude larger than commercial membranes, and can highly efficiently separate 5 and 15 nm gold nanoparticles from their mixtures. The newly developed nanoporous membranes have a wide application in separation and purification of biomacromolecules and nanoparticles

The LAMOST Survey of Background Quasars in the Vicinity of the Andromeda and Triangulum Galaxies -- II. Results from the Commissioning Observations and the Pilot Surveys

We present new quasars discovered in the vicinity of the Andromeda and Triangulum galaxies with the LAMOST during the 2010 and 2011 observational seasons. Quasar candidates are selected based on the available SDSS, KPNO 4 m telescope, XSTPS optical, and WISE near infrared photometric data. We present 509 new quasars discovered in a stripe of ~135 sq. deg from M31 to M33 along the Giant Stellar Stream in the 2011 pilot survey datasets, and also 17 new quasars discovered in an area of ~100 sq. deg that covers the central region and the southeastern halo of M31 in the 2010 commissioning datasets. These 526 new quasars have i magnitudes ranging from 15.5 to 20.0, redshifts from 0.1 to 3.2. They represent a significant increase of the number of identified quasars in the vicinity of M31 and M33. There are now 26, 62 and 139 known quasars in this region of the sky with i magnitudes brighter than 17.0, 17.5 and 18.0 respectively, of which 5, 20 and 75 are newly-discovered. These bright quasars provide an invaluable collection with which to probe the kinematics and chemistry of the ISM/IGM in the Local Group of galaxies. A total of 93 quasars are now known with locations within 2.5 deg of M31, of which 73 are newly discovered. Tens of quasars are now known to be located behind the Giant Stellar Stream, and hundreds behind the extended halo and its associated substructures of M31. The much enlarged sample of known quasars in the vicinity of M31 and M33 can potentially be utilized to construct a perfect astrometric reference frame to measure the minute PMs of M31 and M33, along with the PMs of substructures associated with the Local Group of galaxies. Those PMs are some of the most fundamental properties of the Local Group.Comment: 26 pages, 6 figures, AJ accepte

Polar cap patch transportation beyond the classic scenario

We report the continuous monitoring of a polar cap patch, encompassing its creation, and a subsequent evolution that differs from the classic behavior. The patch was formed from the storm-enhanced density plume, by segmentation associated with a subauroral polarization stream generated by a substorm. Its initial antisunward motion was halted due to a rapidly changing of interplanetary magnetic field (IMF) conditions from strong southward to strong eastward with weaker northward components, and the patch subsequently very slowly evolved behind the duskside of a lobe reverse convection cell in afternoon sectors, associated with high-latitude lobe reconnection, much of it fading rapidly due to an enhancement of the ionization recombination rate. This differs from the classic scenario where polar cap patches are transported across the polar cap along the streamlines of twin-cell convection pattern from day to night. This observation provides us new important insights into patch formation and control by the IMF, which has to be taken into account in F region transport models and space weather forecasts