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High purity alumina ceramics (99% Al2O3) was implanted by copper ion and titanium ion in a metal vapour vacuum arc (MEVVA) implanter, respectively. The influence of implantation parameters was studied varying ion fluence. The samples were implanted by 68 keV Cu ion and 82 keV Ti ion with fluences from 1 × 1015 to 1 × 1018 ions/cm2, respectively. The as-implanted samples were investigated by scanning electron microscopy (SEM), glancing X-ray diffraction (GXRD), scanning Auger microscopy (SAM), and four-probe method. Different morphologies were observed on the surfaces of the as-implanted samples and clearly related to implantation parameters. For both ion implantations, the sheet resistances of the alumina samples implanted with Cu and Ti ion fluences of 1 × 1018 ions/cm2, respectively, reached the corresponding minimum values because of the surface metallization. The experimental results indicate that the high-fluence ion implantation resulted in conductive layer on the surface of the as-implanted high purity alumina ceramics.

Three kinds of structures precipitated from the A gall of a patient were observed on the same samples by a field emission gun-scanning electron microscope (FEG-SEM). They were branching fractal structures, dendritic structures, and irregular crystalline grains. The fractal structures consisted of numerous granules that mostly disconnected each other. The dendrites were connected basically together. The tiny crystalline grains were of complicated shapes. A precipitation-aggregation-branching (PAB) model was used to explain growth mechanism of the fractal structure. Energy dispersive X-ray spectroscopy (EDS) was employed to measure chemical composition of three kinds of precipitates, as well as the A gall matrix. The experimental results reveal that saline or salt played an important role to the formation of the fractal structure, and also to that of the dendritic structure and crystalline grain. There may be relationship between the fractal in the A gall sample and fractal in gallstones. (c) 2005 Elsevier B.V. All rights reserved.

Driven by the need to prevent crystallization of normal alkanes from diesel fuels in cold climates, the petroleum industry has developed additives to slow the growth of these crystals and alter their morphology. While the utility of such additives has been proven at the operational level, few studies have directly monitored their effect at microscopic scales. Here, we present a study of such additives in model n-alkane systems. We find a dramatic effect on the growth morphology: rather than the usual plate-like growth exhibited by pure wax, we see highly branched microcrystalline meshes. Under certain conditions, these meshes form well-defined bands with spacings larger than 200 μm. We suggest that successive bands form by nucleation via a metastable phase ahead of the inhibited growth front.

Polytetrafluoroethylene (PTFE) was irradiated by a high-flux nitrogen ion beam. The influence of experimental parameters was investigated by varying ion beam energy from 2 to 20 keV with the same flux of 1.4×10 17 ions/cm 2 . XPS, SEM, AFM, and wettability were employed to study structures and properties of the treated PTFE samples. All of the as-irradiated samples were aged in air for 1 year. After aging, five chemical bonds, CF 3 , CF 2 , CF, CO, and carbon bonds were observed on the surfaces of the aged samples. The intensities of various chemical bonds changed with increasing ion beam energy. The surface-restructuring behavior was observed on the surfaces of the aged samples irradiated by ion beam with energies of 2 and 5 keV. The surface roughness and water droplet contact angle of the aged PTFE samples irradiated with 2 and 5 keV ion beams improved obviously, and those of the aged PTFE samples irradiated with 10 and 20 keV ion beams kept basically no change. The experimental results suggest that the ion beam energy strongly affected the surface chemical bond, microstructure, and wettability of the aged PTFE samples.

The elliptical, angular, and straight line CdO self-organization aggregates, as well as bush-like crystal clusters were observed on the surfaces of both N 〈1 0 0〉 and P 〈1 1 1〉 silicon wafers. The silicon wafers were heated at 580°C for 1 h in an evaporation–deposition device. All of the self-organization aggregates deposited on respective ridgelines of the bush-like crystal clusters. The surface defects of both silicon substrates were investigated. The experimental results suggested that the CdO self-organization aggregates were related closely to the topographic condition of the bush-like crystal clusters, and not related directly to the surface defects of the silicon substrates. It testifies to a self-organized critical behaviour of the dynamical system during the vapour–solid phase transition.

Si(1 1 1) was implanted by copper ions with different doses and copper distribution in silicon matrix was obtained. The as-implanted samples were annealed at 300 and 540 °C, respectively. Formation of copper silicides in as-implanted and annealed samples were studied. Thermodynamics and kinetics of the reaction were found to be different from reaction at copper–silicon interface that was applied in conventional studies of copper–silicon interaction. The defects in silicon induced by implantation and formation of copper silicides were recognized by Si(2 2 2) X-ray diffraction (XRD).

High purity molybdenum was implanted by C ion in a metal vapour vacuum arc (MEVVA) implanter. The influence of implantation parameters was studied by varying ion fluence and ion current density. The samples were implanted by 45 keV C ion with fluences from 1 x 10(15) to 1 x 10(18) ions/cm(2), respectively. The as-implanted samples were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and nanoindenter. Different morphologies were observed on the surfaces of the as-implanted samples due to irradiation damage, and clearly related to implantation parameters. XRD spectra confirm formation of beta-Mo2C with ion fluences equal to or larger than 1 x 10(16) ions/cm(2), and formation of alpha-Mo2C with ion fluence of 1 x 10(18) ions/cm(2). The maximum nanohardness and maximum modulus of the as-implanted samples increased gradually with increasing ion fluence, and reached the corresponding maximum values with ion fluence of 1 x 10(18) ions/cm(2). The experimental results suggest that the structure and properties of the as-implanted Mo samples exhibited strong dependence on implantation parameters. (C) 2003 Elsevier B.V. All rights reserved.

Two-stage precipitation, crystalline growth and fractal growth, were found in boar bile. The precipitates were observed by scanning electron microscope (SEM). The precipitates were of different morphologies and sizes, and could be divided into three groups: the crystal with regular shape, the tree-like fractal aggregate, and ramified tiny aggregate. The crystals accumulated together, and several branch-like structures grew out at the advancing front of the crystal accumulation. The dimension of the fractal aggregate was D = 1.69. The ramified tiny aggregate consisted of numerous clusters that contained many nano-grains with a size in the range of 40-120 rim. Energy dispersive X-ray spectroscopy (EDS) was employed to measure chemical composition of the precipitates and the boar bile matrix. Computer simulation was performed and a precipitation-aggregation-branching (PAB) model was suggested to explain growth mechanism of the fractal aggregate. The experimental results reveal that equilibrium growth and non-equilibrium growth could occur successfully in the boar bile during liquid-solid phase transition. (C) 2003 Elsevier B.V. All rights reserved.

Al2O3/polymer laminate composites were studied by using different surface treatment techniques and different resins. The silane coupling agent TEVS (triethoxyvinylsilane: CH2CHSi(OC2H5)3) was used to enhance the inorganic–organic interface adhesion. The inorganic-organic interface shear strength, the flexural strength, and the work of fracture of the laminate composites were measured through tensile test and three-point bending test. The morphology of inorganic surface and crack propagation was examined by SEM and AFM. The relationship between inorganic-organic interface shear strength and the work of fracture of the laminate composites was investigated. The experimental results suggest that the toughness of the laminate composites related closely to surface status of the matrix, couping agent, and resin. The maximum value of the work of fracture of the laminate composites was 6.1 times that of monolithic alumina. The work of fracture of the laminate composites, which alumina matrices were coated with a layer of epoxy vinyl ester resin (UPR 3201), increased gradually with increasing the interface shear strength. The work of fracture of the laminate composites, on which alumina matrices were coated with a layer of toughened epoxy vinyl ester resin (T-UPR 3201), decreased greatly as the interface shear strength increased.

Well-adhered gamma-Al2O3 coating layers can be formed on FeCrAl metallic supports for the preparation of structured catalysts in diesel particulate filter (DPF) systems using a three-step method-pre-oxidation, primer deposition and coating deposition. The optimal pre-oxidation is at 950 degreesC for 10 h; the optimal primer sol calcination is at 800 degreesC for 3 h; and the optimal gamma-Al2O3 slurry calcination is at 900 degreesC for 2 h. If the oxidation temperature is 1050 degreesC, only 0.5 h is required to obtain almost the same coating adhesion level as at 950 degreesC for 10 h. The data concerning effects of the major preparation parameters (the pre-oxidation time, temperature, primer calcination temperature and the coating calcination temperature) are presented herein. The coating adhesion was measured by ultrasonic adhesion, thermal shock and interface shear strength tests. (C) 2002 Elsevier Science B.V. All rights reserved.

A visual transient of the growth mechanism from crystallization to fractal growth was observed clearly in a drop of boar bile. The growing crystals were replaced by treelike fractal structures during solidification of the sample. It is fascinating to compare the transient with the result observed in SnI2 vapour. They were completely identical, and revealed that under certain conditions a linear growth could be transferred spontaneously into nonlinear growth. It may be possible to consider the transient as a 'bridge' between linear and nonlinear growth, and to develop a quantitative expression of transient dynamics.

Surface modification of three species of PHAs, PHB, P(HB-co-HV) and P(HB-co-HH), were carried out by 40 keV C+ ion implantations at four different doses, 1 × 1012, 1 × 1013, 1 × 1014, and 1 × 1015 ions cm-2. Remarkable changes between the pristine samples and the implanted samples were observed for the FT-IR and XPS spectra. Fibroblast culture was conducted to investigate the surface biocompatibility changes caused by the implantation of C+. From the results of the MTT colorimetric test and the cell morphology observation assessed by SEM, FI and Confocal Laser Scanning Microscopy (CLSM), there were several evidence that the cytocompatibility of the films were improved by ion implantation and the best cytocompatibility was achieved at the ion dose of 1 × 1012 for all the three species of PHAs. Possible explanation is given by correlating the cell adhesion figures with the chemical and physical changes in the modified surfaces. Results show that the PHAs modified by ion implanting could be a promising family of biomaterials for tissue engineering.

Pulsed high-energy-density plasmas were used to process the surfaces of alumina ceramics. The morphology and composition of different parts of the surfaces of the as-processed samples were examined by scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. The distinct morphology of the surfaces of the as-processed samples, particularly smooth areas and pits, was observed and studied. Uniform sub-micrometer particles about 250 nm in diameter were observed in the pits and proved to contain copper. No elemental copper was detected in the smooth areas. The analysis results showed that the plasmas were dusty. X-ray photoelectron spectroscopy was employed to examine the valence of the copper. An adiabatic model was used to explain the observed phenomena. A possible method for rapid finishing of advanced ceramics was proposed.

Polytetrafluoroethylene (PTFE) was irradiated by low energy titanium ion in a metal vapor vacuum arc (MEVVA) implanter. The samples were irradiated with 80 keV Ti ion with fluences from 5×1015 to 5×1017 Ti/cm2, respectively. Transportation of Ion in Matters (TRIM) code was employed to simulate Ti ion irradiation. The as-irradiated samples were investigated by ESCA, SEM and wettability. As increasing ion fluence, various chemical bonds and irradiation-damaged surfaces were observed. The water droplet contact angel of PTFE samples increased gradually with ion fluence. All the as-irradiated PTFE samples were aged in air for 1 year. After aging the surface-restructuring behavior was observed on the surfaces of the samples irradiated with ion fluence equal to or less than 5×1016 Ti/cm2, which resulted in decrease of the droplet contact angle of these samples. The surface roughness change of the aged samples, which were measured by atomic force microscopy (AFM), was consistent with the droplet contact angle change. The experimental results revealed that Ti ion fluence closely affected the surface chemical bond, morphology and wettability, as well as the aging stability of the as-irradiated PTFE samples.

Surface metallization of alumina ceramics was carried out by pulsed high energy density plasma (PHEDP). A layer of copper film was deposited on the surface of alumina ceramics. Scanning auger electron microscopy (SAM) analysis revealed that copper diffused deep into the alumina substrate. Bonding of alumina and copper film was good. The reaction between copper and alumina was studied by X-ray diffraction (XRD) analysis. A copper aluminum oxide unstable at high temperature and very difficult to be synthesized, cubic phase CuAl2O4, was detected. A kinetics complexity in reaction of PHEDP and ceramics was discussed. An adiabatic model was used to describe heating and quenching of the PHEDP processing and analyze the interaction between PHEDP and alumina ceramics. The experimental results suggest that PHEDP method is a useful technology for various metal-ceramics bonding. (C) 2002 Elsevier Science B.V. All rights reserved.

Polytetrafluoroethylene (PTFE) was implanted by 40 keV carbon ion in a Metal Vapor Vacuum Arc (MEVVA) implanter. The influence of implantation parameters was studied by varying ion fluence from 5 x 10(15) to 5 x 10(17) ions/cm(2). Characterization of the as-implanted samples was performed by electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and wettability. With increasing ion dose, various chemical bonds and irradiation-damaged structures were observed, and droplet contact angle of the samples increased gradually. All the as-implanted PTFE samples were aged in air for 1 year. After aging the surface-restructuring behavior was observed on the surfaces of the samples implanted with ion fluences equal to or less than 5 x 10(16) ions/cm(2). The experimental results revealed that ion fluence strongly affected the surface chemical composition, morphology, and wettability of the as-implanted samples, as well as the aging stability. (C) 2002 Elsevier Science B.V All rights reserved.

Polytetrafluoroethylene (PTFE) was implanted in vacuum by N ions. The influence of experimental parameters was studied by varying ion energy from 2 to 20 keV with the same fluence of 1.4×10 17 ions / cm 2 . The ion energy strongly affected the surface composition, microstructure, and wettability of PTFE. Five chemical bonds, CF3, CF2, CF, C–O, and elemental carbon bonds, were observed on the surface of all the as-implanted samples. The content of the various chemical bonds changed with increasing ion energy. The content of elemental carbon bond reached a maximum value of 45.81% on the surface of the sample implanted with ion energy of 5 keV. Displacement of the binding energies of the C 1s peak components was observed on the surfaces of samples implanted with ion energies equal to or greater than 5 keV. Numerous microfibers drawn up in the same orientation were observed on the ion-irradiated surfaces. The droplet contact angle of the as-implanted samples increased gradually with increasing ion energy, and reached a maximum value of 117.4° on the surface of the sample implanted with ion energy of 20 keV.

The ultimate goal of an advanced turbocharger development is to have a superior aerodynamic performance while having the turbocharger survive various real world customer applications. Due to the uncertainty of customer usage and driving pattern, the fatigue life prediction is considered one of the most ambiguous analyses in the entire design and analyses processes of the turbocharger. The turbocharger system may have various resonant frequencies, which may be within the range of turbocharger operation for automotive applications. A turbocharger may operate with excessive stresses when running near resonant frequencies. The turbocharger may experience fatigue failures if the accumulative cycles of the turbocharger running across the resonant frequencies exceeds a certain limit. In this study, the authors propose an alternative approach to mitigate this kind of fatigue issues: i.e. engine system approach to improve turbocharger fatigue life via avoiding operating the turbocharger near resonant speeds for extended period of time. A preliminary numerical study was made and presented in this paper to assess the feasibility of such an engine system approach, which is followed by an engine dynamometer test for engine performance sensitivity evaluation when the turbocharger operation condition was adjusted to improve the high cycle fatigue life. The study shows that for a modern diesel engine equipped with electrically controlled variable geometry turbine and EGR for emission control, through the engine calibration and control upgrade, turbocharger operation speed can be altered to stay away from certain critical speeds if necessary. The combined 1D and 3D numerical simulation shows the bandwidth of the turbine “risk zone” near one of the resonant speeds and the potential impact on engine performances if the turbocharger speed has to be shifted out of the “risk zone.”

The surface modification of polytetrafluoroethylene (PTFE) was carried out by carbon ion implantation. The influence of implantation parameters was investigated by varying ion dose over a wide range. The samples were implanted with 20 keV carbon ion with doses from 5 x 10(15) to 5 x 10(17) ions cm(-2), and examined by ESCA, XRD, SEM, and wettability. Five chemical bonds were formed on the surfaces of as-implanted samples, and their content changed as a function of ion dose. The crystallinity of the as-implanted samples increased gradually with increasing ion dose. Various radiation damage structures were observed. The values of droplet contact angle of the as-implanted samples increased gradually with increasing ion dose, and was very sensitive to the environmental humidity under which the droplet contact angle was measured. The experimental results show that the surface chemical bond, crystallinity, morphology, and wettability of as-implanted PTFE samples are closely dependent on the carbon ion dose. (C) 2001 Elsevier Science B.V. All rights reserved.

Polytetrafluoroethylene (PTFE) was implanted by titanium ions in a MEVVA (MEtal Vapour Vacuum Arc) implanter. The influence of implantation parameters was studied by varying the ion dose over a wide range. The samples were implanted with 40 keV Ti ions with doses from 5 x 10 15 to 5 x 10 17 Ti/cm 2 , and investigated by ESCA, XRD, SEM, and wettability. All the as-implanted PTFE samples here aged in air for one year. After aging the surface-restructuring behavior was observed on the samples implanted with doses of 5 x 10 15 , 1 x 10 16 , and 5 x 10 16 Ti/cm 2 . The water contact angle of all the aged samples decreased to a certain extent except for the sample implanted with a dose of 5 × 10 17 Ti/cm 2 . The experimental results suggest that the surface chemical bond, morphology, wettability, and aging stability of as-implanted PTFE samples exhibited fairly strong dependence on the ion dose.

The morphologies of the deposits SnI2 and CdI2, which formed on the surface of a silicon crystal during vapor-solid transition, were studied. The SnI2 fractal structures and the CdI2 self-organizing structures were observed by scanning electron microscopy. It is most significant that the SnI2 fractal structures were composed of nanograins grown at the advancing front of SnI2 crystal accumulation, and showed a transient from equilibrium to non-equilibrium growth. The transient occurred as the cooling rate was increased up to 1000 K/min. The CdI2 self-organizing sunflower-like structures were composed of CdI2 nanocrystals, and indicated an anomalous growth mechanism. The experimental results suggest that the iodide thin films can give rise to fractal structures or self-organizing structures resulting from non-equilibrium growth processes.

CoSi2 thin layers were fabricated by Co-ion implantation into Si(100) and subsequent annealing. The ion implantation was carried out in a metal vapour vacuum are (MEVVA) source implanter. Various doses of Co ions were implanted using doses of 1.6 x 10(17) to 7.5 x 10(17) Co/cm(2) at an extraction voltage of 40 kV and ion current densities of 60 and 150 mu A/cm(2). It was found that the thicknesses of continuous CoSi2 layers after annealing within Si(100) increased with increasing implantation dose, and ranged from 43 to 60 nm for the implantation doses used in this work. The specific resistivity of implanted samples after annealing was between 12.1 and 13.8 mu Omega cm at room temperature. The results indicated that the ion current density played an important role in the structure of the CoSi2 layer, and annealing can significantly improve the electrical property of the CoSi2 layers.

The evaporation-deposition process of SnI2 was studied experimentally. Two different kinds of aggregate structures were obtained, i.e., the grain aggregate and cluster aggregate. It is suggested that localized conditions of nucleation and growing, long-range correlations, and interaction between SnI2 crystals may be involved in the growth process of SnI2 aggregates.

Polycystic kidney disease (PKD), the most common life threatening genetic disease and affects approximately 1:400 people in the US including significant numbers of Active Duty Military personnel, Veterans and their beneficiaries. In PKD, the affected renal epithelia form cysts, eventually destroying renal architecture and function, leading to chronic kidney disease and end stage renal disease. There is currently no specific therapy for PKD. The present research examines the innovative translational therapy of intravenous administration of adult renal tubule cells containing the wild type (normal) PKD Pkhd1 gene in experimental PKD (the PCK rat model). The aim is to replace abnormal renal epithelia while avoiding the morbidity and mortality of surgery. Expansion of cells in vitro will also extend the utility of organs available for transplant. Data obtained to date demonstrate markedly lower renal cyst volume and fibrosis and better kidney function with cell transplantation. There are two potential mechanisms of action, either transfer of genetic material via exo-RNA or re-orientation of the cystogenic phenotype by correction of abnormalities in planar polarity. These results are the basis for an additional funding pre-application to extend the present studies, ultimately to prevent or treat kidney failure in humans. The results will also be presented at the Annual Meeting of the American Society of Nephrology in November, 2013.

Boric acid crystals grow from aqueous solutions and climb up a piece of soda glass. These crystals form numerous tree-like ramified patterns. They clearly exhibit self-similar feature and can be considered as fractal formations. The fractal dimensions of the patterns grown at 30-degrees-C range from 1.62 to 1.70. The experimental results reveal that the bifurcation growth of boric acid crystals depends strongly on the type of material and the surface conditions of the substrate. There is no bifurcation pattern on the surface of polyvinyl chloride, stainless steel, lead foil, and glass coated with a layer of vaseline. A tentative transport model to explain the observed phenomena is presented.

In this paper, a new concept that is Circulation Course Resources (CCR) is introduced, which means the course resources circulating from the students listening in classroom lecture, camera shooting, video coding, video storage, video server to the students learning from VOD. The creating course video system and network-teaching system as parts of CCR architecture are presented separately. To connect the two systems, a middle system defined as Bridge System is designed and modeled with UML. The core application design of the Bridge System is expressed by the classes design and main database design. The functions of Bridge System include making the course videos flowing from one system to another automatically and converting the important data of the two systems into uniform format. The CCR architecture has been put into action and achieved satisfied results.

The axial thrust load of a turbocharger is generated due to the pressure differential between the compressor and turbine. Changes in compressor and turbine geometry and variations in test conditions can influence the thrust load. Once the axial force exceeds the loading capacity limit of a thrust bearing, the balance of the thrust bearing system cannot be maintained, which may lead to a catastrophic failure of the turbocharger. In this paper, a fault diagnosis of a turbocharger that experienced a catastrophic failure during flow bench testing is analyzed. A detailed analysis of a turbocharger thrust load, based on empirical formulae and CFD verification, is presented. The thrust prediction at high rotation speed is helpful for further flow bench testing and to avoid the future turbocharger failure. NOMENCLATURE c C_a1 Axial velocity at compressor inlet c T_a6 Axial velocity at turbine exit Cpa Specific heat of air at constant pressure Cpe Specific heat of Exhaust gas at constant pressure Fc Resultant force of compressor side Fc1 Axial force at compressor wheel inlet Fc2 Axial force at compressor wheel shroud Fc3 Axial force at compressor wheel back face Ft Resultant force of turbine side Ft1 Axial force at turbine wheel shroud Ft2 Axial force at turbine wheel exit Ft3 Axial force at turbine wheel back face FTC Resultant force of turbocharger k Ratio of specific heats mC Compressor mass flow rate mT Turbine mass flow rate pC00 Total pressure at compressor inlet pC1 Static pressure at compressor inlet pC2 Static pressure at compressor impeller exit pC5 Static pressure at compressor diffuser exit pC_shroud(r ) Static pressure distribution along the compressor wheel shroud pC_backface(r ) Static pressure distribution along compressor wheel back face pColl Total pressure at compressor exit pT00 Total pressure at turbine inlet Proceedings of ASME Turbo Expo 2010: Power for Land, Sea and Air GT2010 June 14-18, 2010, Glasgow, UK

The network education has been applied widely in universities. The use of multimedia teaching resouces is more important. It is a great amount of workload that the course streaming media as a main type teaching resouces is created. So, we developed an auto-creating course streaming media system to solve the problem. The course streaming media can be created automatically according to the course schedule by the system. The system is composed of course recording subsystem and distance management subsystem. The course recording subsystem functions cameras control, video and audio collections and streaming video creating. The distance management subsystem can implement system management and monitor in deferent place by Internet. The course streaming created by the system adopted WMV9 criterion. A lot of valuable course videos have been made by the system in recent two years. These course videos have been applied in network teaching and achieved gratifying results.

A photoluminescence (PL) study of ZnSe-ZnS strained-layer superlattice (SLS) on a transparent substrate, CaF 2 , grown by atmospheric pressure metalorganic chemical vapour deposition (AP-MOCVD) is presented. Two absorption bands and three emission bands in the SLS were observed for the first time under low excitation. The origin of some bands might be ascribed to the excitonic transition of n = 1 heavy and light hole.

Excitonic properties are investigated of ZnSe1−xSx epilayer fabricated on GaAs substrate by a Ap-MOCVD. Luminescence, excitation, and time-resolved spectroscopy are employed to study the interaction between excitons and electrons at 77 and 300 K. Under pulsed N2 laser excitation it is found that the peak shift of the near band edge emission are more large, especially at room temperature. This is due to the fact that the bottoms of the conduction bands are filled at the higher temperature, so the carriers from the exciton-exciton scattering must occupy higher energy levels. Therefore a shift of the peak towards lower energy is expected. Es werden die Anregungseigenschaften von ZnSe1−xSx-Epitaxieschichten untersucht, die mittels Ap-MOCVD auf GaAs-Substraten hergestellt werden. Lumineszenz, Anregung und zeitaufgeloste Spektroskopie werden benutzt, um die Wechselwirkung zwischen Exzitonen und Elektronen bei 77 und 300 K zu untersuchen. Unter N2-Impulslaseranregung wird gefunden, das die Maximumverschiebung in der Nahe der Bandkantenemission groser ist, insbesondere bei Zimmertemperatur. Dies wird dadurch verursacht, das die unteren Kanten der Leitungsbander bei hoherer Temperatur gefullt sind; die Trager aus der Exziton-Exziton-Streuung mussen hohere Energieniveaus besetzen. Deshalb wird eine Verschiebung des Maximums zu niedrigen Energien erwartet.

SUMMARY HIV-1 Nef plays important roles in HIV-1 replication and pathogenesis. It is translated from completely spliced HIV-1 RNA, and its expression is inherently regulated at the levels of viral DNA transcription and RNA splicing. Here we show that Sam68 cytoplasmic mutants potently suppress Nef expression. The suppression requires Sam68 domain aa 269–321 and is correlated with its ability to induce stress granules. In addition, the suppression is specific to Nef, and direct binding to nef mRNA 3 0 UTR confers the suppression specificity. Furthermore, nef mRNA is targeted to and enriched in these induced stress granules. Importantly, Nef suppression occurs in the context of HIV-1 infection of CD4 + T lymphocytes with little MHC I and CD4 downregulation. Taken together, these results demonstrate that stress granule induction and nef mRNA sequestration account for this translational suppression of Nef expression and offer a strategy for development of anti-HIV therapeutics to buttress our fight against HIV/AIDS.

The vibration property of turbocharger turbine blade was analyzed with thermal load and centrifugal force of the turbocharger turbine considered. Vibration property was analyzed by FEM and validated by dynamic stress test. Through the analysis of resonance property, the design guideline was put forward.

The lab developed a high pressure ratio turbocharger with high efficiency, which has pressure ratio of 3.5 and efficiency of 60%. Structure feature of the turbocharger and design process of the compressor impeller, turbine, and bearing system are described. Experiment results of the turbocharger and application of matching it with a diesel engine are also included.

A numerical investigation into aerodynamic features of the mixed flow turbine used in a high pressure ratio turbocharger was conducted. The S-A turbulence model and Jameson’s center scheme have been applied in order to get good viscous resolution, accuracy and computing efficiency. Limiting streamlines on the wall surface as well as different flow characteristics, such as entropy generation of the cross sections, were evaluated, while detailed endwall flow and secondary flow structure were analyzed. The development of different vortex, especially the tip leakage vortex, passage vortex and horseshoe vortex were discussed. The results have shown that there is a great secondary flow feature and complicated vortex system in the mixed flow turbine.Copyright © 2008 by ASME

Quasi-two-dimensional molybdenum oxide (MoO3) leaves grow during vapor-phase deposition at 900°C. The disordered kinetic growth processes produce molybdena leaves with self-similar fractal properties, which consist of many single crystal whiskers of molybdena. Besides the molybdena leaves, some bush-like crystals are also found under the same experimental condition. The structure of the molybdena leaves is a sort of diffusion-limited cluster aggregation (DLCA) with a fractal dimension of D = 1.83. Les feuilles d'oxyde de molybdene (MoO3) deux dimensionnel viennent de croitre dans les depots phase vapeur a 900°C. Les processus de croissance de disordance dynamique viennent de produire les feuilles d'oxyde de molybdene avec les caracteres de self-similaire fractal. Elles ont ete consistees en beaucoup de cristaux en aiguile d'oxyde de molybdene. Outre ces feuiles, quelques cristaux comme l'arbuste ont ete aussi decouvert sous la meme condition experimentale. La structure des feuilles d'oxyde de molybdene est une sorte de Diffusion-Limite Groupe Condensation avec D = 1,83 de dimension fractal.

Design of variable nozzle vane is the key for variable nozzle turbocharger (VNT) design. A VNT was constructed by assembling a variable nozzle into a conventional turbocharger with vaneless nozzle. The design methods and processes of the variable nozzle were presented in detail, which include thermodynamic design, structural and mechanical design, and CFD analysis. The CFD analysis showed that the aerodynamic performance of the variable nozzle was well accepted in different open positions. The engine-matching test showed that, the performance of the engine improved significantly with the VNT compared to the prototype turbocharger. The engine fuel consumption was reduced by 8.1g/Kw·h and the maximum torque increased by 250 N·m.Copyright © 2007 by ASME

Autosomal recessive polycystic kidney disease is a truly catastrophic monogenetic disease, causing death and end stage renal disease in neonates and children. Using PCK female rats, an orthologous model of autosomal recessive polycystic kidney disease harboring mutant Pkhd1, we tested the hypothesis that intravenous renal cell transplantation with normal Sprague Dawley male kidney cells would improve the polycystic kidney disease phenotype. Cytotherapy with renal cells expressing wild type Pkhd1 and tubulogenic serum amyloid A1 had powerful and sustained beneficial effects on renal function and structure in the polycystic kidney disease model. Donor cell engraftment and both mutant and wild type Pkhd1 were found in treated but not control PCK kidneys 15 weeks after the final cell infusion. To examine the mechanisms of global protection with a small number of transplanted cells, we tested the hypothesis that exosomes derived from normal Sprague Dawley cells can limit the cystic phenotype of PCK recipient cells. We found that renal exosomes originating from normal Sprague Dawley cells carried and transferred wild type Pkhd1 mRNA to PCK cells in vivo and in vitro and restricted cyst formation by cultured PCK cells. The results indicate that transplantation with renal cells containing wild type Pkhd1 improves renal structure and function in autosomal recessive polycystic kidney disease and may provide an intra-renal supply of normal Pkhd1 mRNA.

Clinical studies indicate that Neisseria gonorrhoeae (gonococci (GC)) has the capacity to enhance HIV type 1 (HIV-1) infection. We studied whether GC enhances HIV infection of activated dendritic cells (DCs). The results show that GC can dramatically enhance HIV replication in human DCs during coinfection. The GC component responsible for HIV infection enhancement may be peptidoglycan, which activates TLR2. TLR2 involvement is suggested by bacterial lipoprotein, a TLR2-specific inducer, which stimulates a strong enhancement of HIV infection by human DCs. Moreover, participation of TLR2 is further implicated because GC is unable to stimulate expression of HIV in DCs of TLR2-deficient HIV-1-transgenic mice. These results provide one potential mechanism through which GC infection increases HIV replication in patients infected with both GC and HIV.

The front propagation of a single crystallizing domain has been well studied for more than a century. In many important crystallization processes, however, multiple domains grow simultaneously, resulting in a multicrystalline, meshlike aggregate. This is the typical case for organic compounds, including polymers and alkanes. We have studied such growth in the case of a normal alkane precipitating from solution in the presence of kinetic inhibitors--additives which, when present in trace amounts, have a dramatic effect on growth kinetics and morphology. In this case, we observe a distinct banded growth with a typical length scale of 300 microm superimposed on the finer mesh structure. We present a simple continuum model that demonstrates the essential behavior of this growth.

Human immunodeficiency virus type 1 (HIV-1) replication requires active nuclear export of unspliced and incompletely spliced HIV-1 RNA transcripts. This process is evolutionally made possible by expression of HIV-1 Rev, one of the three HIV-1 proteins encoded by completely spliced HIV-1 RNAs. Evidence has accumulated to suggest that Sam68 plays an important role in HIV-1 replication through HIV-1 Rev protein. In the present study, we further examined the structure-function relationship of Sam68 protein in relation to HIV-1 replication. We identified a Sam68 domain located between aa269 and aa321 to be involved in the HIV-inhibitory effects of Sam68 dominant negative mutants lacking the nuclear localization signal (NLS). Deletion of this domain abrogated inhibition of HIV-1 replication by these mutants. HIV-1 Rev protein appeared to mediate the HIV-inhibitory effects of these mutants and by this domain, as assessed by Rev-dependent chloramphenicol acetyltransferase reporter gene assay, in trans rev-defective HIV-1 complementation assay, and RNase protection assay. The HIV-inhibitory mutants containing this domain were further found to have diminished binding affinity to the wild-type Sam68 and to be associated with cytoplasmic retention of exclusively nuclear localized wild type Sam68. Taken together, these results further ascertain the important role of Sam68 in HIV-1 Rev function and viral replication, and suggest that the HIV-inhibitory effects of Sam68 dominant negative mutants directly result from their binding to endogenous Sam68 and their interference with nuclear localization of endogenous Sam68.

The PWM inverter fed linear synchronous motor (LSM) drive system in the TRANSRAPID Shanghai is an important load for local power system. As a heavy nonlinear load, it brings great harmonics into power supply system. This paper deals with harmonic analysis of the PWM inverter fed LSM drive system in the TRANSRAPID Shanghai. The four parts of drive system are analyzed in the paper, including LSM with a feeder cable, the SPWM inverter, the DC link and the converter. Models of these parts are set up respectively and relatively. With these models, load current harmonics, harmonics in the DC link and line current harmonics, including characteristic harmonics and inter-harmonics are analyzed step by step in this paper. Finally, an analysis result is given at some typical running condition. It is found that the harmonics at 20 kV PCC exceed the permitted value of the Chinese national standard when no additional harmonic compensator is adopted in power supply system of the TRANSRAPID Shanghai.

${\mathrm{MoO}}_{3}$ powder was used as source material and heated at 650 and 750 \ifmmode^\circ\else\textdegree\fi{}C in a particular oxidizing ambient. Some two-dimensional fractal patterns and crystal strings of the molybdena grow during the phase transformation. The experimental observations support the diffusion-limited-cluster-aggregation model and the Random-rain model. X-ray diffraction experiments show that the ${\mathrm{MoO}}_{3}$ crystal strings are single crystals.

Rutherford backscattering spectrometry (RBS), the Laue X-ray method and electron spectroscopy for chemical analysis (ESCA) have been combined to study a crystal ribbon of molybdenum oxide. The crystal ribbon was grown after properly heating a molybdenum polycrystalline substrate at 900 ° C in an oxidizing ambient. The dimensions of the crystal ribbon are 21.5 mm in length, 1.2 mm in width, and 2800 A in thickness, as measured by RBS. It is flexible and transparent with two shiny surfaces. The Laue X-ray pattern shows that the crystal ribbon is a single crystal, and the lauegrams are very sensitive to the crystal thickness. There are perfect lauegrams for the 2800 A thick specimen, while some enlarged spots were observed for another, thinner specimen, because of the distortion in the crystal lattice. Both RBS and ESCA show that the single crystal is analytically pure and it is expected to be a kind of molybdena crystal; the stoichiometric formula is MoO 2.8 . A possible explanation of the crystal growth is mentioned in the present work.