Solid state extrusion of polymers through convergent-divergent dies

Compared with metals, polymer materials have Iow strength and stiffness. However, molecular orientation can enhance many mechanical properties of polymer materials in the direction of orientation. Studies on solid state polymer extrusion (Le. extrusion carried out at temperatures below the melting point of the polymer) through convergent dies show that it is possible to produce extrudates exhibiting a high degree of monoaxial orientation in the extrusion direction. Although the strength of these extrudates has been greatly enhanced in the orientation direction, the strength decreases in the transverse direction to the axial orientation. Biaxially oriented polymer materials, on the other hand, show increased mechanical properties in more than one direction. But so far, extrusion processes that confer orientation in more than one direction have not received much attention. The present work is concerned with the development of biaxial orientation in thick thermoplastics extrudates by extrusion through dies exhibiting simultaneously converging and diverging walls perpendicular to each other and with a cross-section area at the die entry being the same as at the exit. Four die designs are examined, known respectively as the dual-taper die, the expansion fish-tail die, the constant fish-tail die and the cross die, using polytetrafluoroethylene and ultra-high molecular weight polyethylene. Measurements of birefringence and tensile strength on sections of the extrudates have shown that a preferential orientation along the transverse direction is normally achieved with the fish-tail dies and the dual-taper die, while the extrudates obtained with the cross die were found to exhibit a cross-ply orientation pattern with a bias in the extrusion direction for outerlayers and a preferential orientation in the transverse direction for the middle layers. The mechanics of the processes has been analysed by a plasticity approach for solid state extrusion, and by using variable wall boundaries for the melt extrusion analysis. The extrusion pressure predicted by the analysis compares very well with the values measured experimentally

The Competition of Passenger Transport and the Increase of Passenger Train Speed in China: A Review and Prospects

The purpose of this paper is to consider the current situation of passenger transport competition among modes, the progress of increasing the competitive capacity of Chinese Railways (CR) , mainly by raising the speed of passenger trains, and possible future developments. The first part describes the past and current situation of passenger transport in China, from the market in which the supply, dominated by rail, did not satisfied the demand to the market in which the supply which is becoming a little bit over the demand, due to the economic reform and open door policy adopted by Chinese Government. The situation of the passenger transport competition between different modes in different market segment in terms of tariff and service level (speed, frequency and comfortable) and change of market share, are then described. In the following section the key efforts that CR adopted to increase its competitive capacity in the passenger transport – upgrading the existing line and improving the rolling stocks to raise the running speed of passenger trains, running diversified passenger trains, increasing the frequency of passenger train, opening some passenger service market to private or non railway firm and so on – and its effects are then described. Finally, the possible future development of passenger transport in CR, in the fields of competition, ownership and organization reform, and price deregulation, are considered.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

The Competition of Passenger Transport and the Increase of Passenger Train Speed in China: A Review and Prospects

The purpose of this paper is to consider the current situation of passenger transport competition among modes, the progress of increasing the competitive capacity of Chinese Railways (CR) , mainly by raising the speed of passenger trains, and possible future developments. The first part describes the past and current situation of passenger transport in China, from the market in which the supply, dominated by rail, did not satisfied the demand to the market in which the supply which is becoming a little bit over the demand, due to the economic reform and open door policy adopted by Chinese Government. The situation of the passenger transport competition between different modes in different market segment in terms of tariff and service level (speed, frequency and comfortable) and change of market share, are then described. In the following section the key efforts that CR adopted to increase its competitive capacity in the passenger transport – upgrading the existing line and improving the rolling stocks to raise the running speed of passenger trains, running diversified passenger trains, increasing the frequency of passenger train, opening some passenger service market to private or non railway firm and so on – and its effects are then described. Finally, the possible future development of passenger transport in CR, in the fields of competition, ownership and organization reform, and price deregulation, are considered.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Linguistic and Cultural Adaptation of Mongolian Ecological Immigrants in the Border City

本文以内蒙古二连浩特市蒙古族生态移民 社区为调查地，根据行为适应、语言文化态度、 族际通婚和跨境婚姻等变量，分析当前边境地 区少数民族生态移民的语言文化适应以及文化 心理、身份认同等问题。新时期边境地区的民 族工作，要把发展作为解决问题的根本途径， 完善城镇社会保障体系，提升民族教育和职业 培训质量，加大文化惠民工程力度，丰富边境 口岸城市的语言文化生活，满足生态移民的精 神文化需求。恰当处理语言文化关系，发挥语 言文化的固边作用，有助于巩固和发展和谐的 民族关系。 This is a case study in Erenhot City, Inner Mongolia Autonomous Region on Mongolian ecological immigrants’ linguistic and cultural adaptation as well as the cultural psychology and related identity issues according to the attitudes towards residence patterns, marriage, language, culture and other variables. Based on the data analysis, the study puts forward the suggestions of the current work with regard to ethnic groups. To solve the problems of the immigrants’ adaptation, the vital method is the economic and social development, including improving the system of urban social security, raising the quality of ethnic education and vocational training, increasing the intensity of culture projects, and enriching the cultural life of border cities to satisfy the spiritual and cultural needs of ecological migration. Proper handling the relationship between language and culture makes a significant contribution to the consolidation and development of the harmonious ethnic relationshi

Intrinsically disordered proteins link alternative splicing and post-translational modifications to complex cell signaling and regulation

Intrinsically disordered proteins and regions (IDPs and IDRs) lack well-defined tertiary structures, yet carry out various important cellular functions, especially those associated with cell signaling and regulation. In eukaryotes, IDPs and IDRs contain the preferred loci for both alternative splicing (AS) and many post-translational modifications (PTMs). Furthermore, AS and/or PTMs at these loci generally alter the signaling outcomes associated with these IDPs or IDRs, where the functional cooperation of these three features is named the IDP-AS-PTM toolkit. However, the prevalence of such functional modulations remains unknown. Also, the signal-altering mechanisms by which AS, and PTMs modulate function and the extent to which AS and PTMs collaborate in their signaling modulations have not been well defined for particular protein examples. Here we focus on three important signaling and regulatory IDR-containing protein families in humans, namely G-protein coupled receptors (GPCRs), which are transmembrane proteins, the nuclear factors of activated T-cells (NFATs), which are transcription factors (TFs), and the Src family kinases (SFKs), which are signaling enzymes. The goal here is to determine how AS and PTMs individually alter the outcomes of the signaling carried out by the various IDRs and to determine whether AS and PTMs work together to bring about differential cellular responses. We also present data indicating that a wide range of other signaling IDPs or IDRs undergo both AS- and PTM-based modifications, suggesting that they, too, likely take advantage of signal outcome modulations that result from collaboration between these two events. Hence, we propose that the widespread cooperation of IDPs, AS and/or PTMs provides a IDP-AS-PTM toolkit and substantially contributes to the vast complexity of eukaryotic cell signaling systems

Gate defined quantum dot realized in a single crystalline InSb nanosheet

Single crystalline InSb nanosheet is an emerging planar semiconductor material with potential applications in electronics, infrared optoelectronics, spintronics and topological quantum computing. Here we report on realization of a quantum dot device from a single crystalline InSb nanosheet grown by molecular-beam epitaxy. The device is fabricated from the nanosheet on a Si/SiO2 substrate and the quantum dot confinement is achieved by top gate technique. Transport measurements show a series of Coulomb diamonds, demonstrating that the quantum dot is well defined and highly tunable. Tunable, gate-defined, planar InSb quantum dots offer a renewed platform for developing semiconductor-based quantum computation technology.Comment: 12 pages, 4 figure

Anisotropic Pauli spin-blockade effect and spin-orbit interaction field in an InAs nanowire double quantum dot

We report on experimental detection of the spin-orbit interaction field in an InAs nanowire double quantum dot device. In the spin blockade regime, leakage current through the double quantum dot is measured and is used to extract the effects of spin-orbit interaction and hyperfine interaction on spin state mixing. At finite magnetic fields, the leakage current arising from the hyperfine interaction is suppressed and the spin-orbit interaction dominates spin state mixing. We observe dependence of the leakage current on the applied magnetic field direction and determine the direction of the spin-orbit interaction field. We show that the spin-orbit field lies in a direction perpendicular to the nanowire axis but with a pronounced off-substrate-plane angle. It is for the first time that such an off-substrate-plane spin-orbit field in an InAs nanowire has been detected. The results are expected to have an important implication in employing InAs nanowires to construct spin-orbit qubits and topological quantum devices.Comment: 20 pages, 5 figures, Supporting Informatio

Microfluidic production of porous chitosan/silica hybrid microspheres and its Cu(II) adsorption performance

AbstractWaste water with heavy metal ions has been of great concern because of its increased discharge, toxic and some other bad effects on human beings or the environment. In this article, monodispersed chitosan/silica hybrid microspheres with porous structure and large specific surface area were successfully prepared by using microfluidic technology and they have advantages in mechanical property and adsorption of heavy metal ions such as Cu(II). In the optimum condition, porous chitosan/silica hybrid microspheres with 1.0wt.% TEOS in the dispersed phase and pre-solidified for 3h have enhanced mechanical intensity, faster adsorption kinetic and larger equilibrium adsorption amount of Cu(II) compared to the porous chitosan microspheres. The mechanical intensity and adsorption rate of the porous hybrid microspheres were 1.5 times and two times of porous chitosan microspheres, respectively. Meantime, the adsorption capacity was increased by 25%. The porous hybrid microspheres have good potentials in the applications of removing heavy metal ions from waste water

Single Nucleotide Polymorphisms of MicroRNA Processing Machinery Genes and Outcome of Hepatocellular Carcinoma

MicroRNA (miRNA)-related single nucleotide polymorphisms (miR-SNPs) can affect cancer development, treatment efficacy and patients prognosis. We examined 6 miR-SNPs in miRNA processing machinery genes including exportin 5 (XPO5) (rs11077), Ran-GTPase (RAN) (rs14035), Dicer (rs3742330), Trinucleotide Repeat Containing 6B (TNRC6B) (rs9623117), GEMIN3 (rs197412), GEMIN4 (rs2740348) in 108 surgically resected HCC patients and evaluated the impact of these miR-SNPs on HCC outcome. Among the 6 SNPs, only the A/A genotype of rs11077 located in XPO5 3′UTR was identified to associated independently with worse survival in HCC patients by multivariate analysis with relative risk, 0.395; 95% CI, 0.167–0.933; p = 0.034. This is the first study reporting that polymorphisms related to miRSNPs have prognostic value in hepatocellular carcinoma and identify the A/A genotype of rs11077 SNP site located in XPO5 3′UTR can help to predict worse prognosis in patients