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Now showing items 17 - 32 of 7016

  • Decreased Cutaneous Resonance Running Time in Cured Leprosy Subjects

    Song, S. P.   Elias, P. M.   Lv, C. Z.   Shi, Y. J.   Guang, P.   Zhang, X. J.   Feingold, K. R.  

    Background/Objectives: Leprosy prominently involves both the skin and peripheral neural tissues and some symptoms persist after microbial cure. Because alterations in the dermis also occur in leprosy, we assessed here whether there were changes in cutaneous resonance running time (CRRT), a parameter that is influenced by collagen properties, in cured leprosy subjects. Methods: A reviscometer was used to measure the CRRT at various directions on the dorsal hand and the flexural forearms of 76 cured leprosy subjects aged 50-85 years and 68 age-matched normal subjects. Results: In comparison to normal subjects, CRRTs on the hands and the forearms were significantly reduced in all directions in cured leprosy, except at the 1-7, 2-8 and 3-9 o'clock directions on the forearms. CRRTs were reduced significantly at both the 4-10 and 5-11 o'clock directions on the forearm in lepromatous (73.33 +/- 4.19 at 4-10 o'clock and 67.44 +/- 2.71 at 5-11 o'clock direction) and borderline lepromatous types (77.58 +/- 5.84 at 4-10 o'clock and 79.85 +/- 6.81 at 5-11 o'clock direction) as compared with normal (143.10 +/- 7.75 at 4-10 o'clock and 125.18 +/- 8.14 at 5-11 o'clock direction). On the hand, CRRTs at all directions, except that at 4-10 o'clock direction, were also significantly reduced in lepromatous and borderline lepromatous types in comparison with normal. Significant differences in CRRT at some directions were found among the various subtypes of leprosy. Conclusion: CRRTs were abnormal in the cured leprosy subjects as a whole, but varied with leprosy subtypes, which suggested that the extent of reduction of CRRTs correlates with the severity of immune alteration. These results suggest that CRRT measurements could be a useful approach to quantify the extent of some residual abnormalities in cured leprosy and perhaps could also be used to evaluate the efficacy of treatment. Copyright (C) 2009 S. Karger AG, Basel
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  • Bond Angle Study of Self-compensating Y(1-x)Ca(x)Ba(2-x)La(x) Cu(3)O(z) System

    Jin, W. T.   Hao, S. J.   Zhang, X. J.   Zhao, Y.   Zhang, H.  

    Single-phase samples of a self-compensating Y(1-x)Ca(x) Ba(2-x)La(x) Cu(3)Oz system were synthesized through a solid-state reaction method with x < 0.4. The structure of all samples were characterized by X-ray diffraction and refined by the Rietveld method. Superconducting properties have been investigated by the DC magnetization measurement. The critical temperature (T(c)) decreases evidently with the increment of x although the carrier concentration remains constant in the samples for different doping level. Careful study of the chemical bonds in the crystalline lattice demonstrates that the T(c) is closely correlated to four pairs of bond angles in the unit cell. The analysis indicates that crystalline structure is one of the important factors to high-T(c) superconductivity, and its influence is independent of the carrier concentration.
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  • Computational fluid dynamic study on cavitation in liquid nitrogen

    Zhang, X. B.   Qiu, L. M.   Gao, Y.   Zhang, X. J.  

    Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper presents the steady computational fluid dynamic (CFD) results of cavitation in liquid nitrogen flow through hydrofoils and ogives with so-called "full cavitation model". The model is reexamined to assess the performance prediction from the standpoint of cryogenic fluids with the assumption of thermal equilibrium between vapor phase and liquid phase. The fluid thermodynamic properties are specified along the saturation line using the "Gaspak 3.2" data-bank. The thermal effects and accompanying property variations due to phase change are modeled rigorously. The thermodynamic cavitation framework is validated against experimental data of NASA hydrofoil and ogive. The global sensibility of the cavitation solution with respect to the cavitation model coefficients and the free-stream velocity is investigated in detail and the choking phenomenon is reported with high Mach number. The full cavitation model with the default coefficients is applicable for cavitation prediction in liquid nitrogen, taking into account of the thermodynamic effects. (c) 2008 Elsevier Ltd. All rights reserved.
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  • Modeling liquid hydrogen cavitating flow with the full cavitation model

    Zhang, X. B.   Qiu, L. M.   Qi, H.   Zhang, X. J.   Gan, Z. H.  

    Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper strives towards developing an effective computational strategy to simulate liquid hydrogen cavitation relevant to liquid rocket propulsion applications. The aims are realized by performing a steady state computational fluid dynamic (CFD) study of liquid hydrogen flow over a 2D hydrofoil and an axisymmetric ogive in Hord's reports with a so-called full cavitation model. The thermodynamic effect was demonstrated with the assumption of thermal equilibrium between the gas phase and liquid phase. Temperature-dependent fluid thermodynamic properties were specified along the saturation line from the "Gaspak 3.2" databank. justifiable agreement between the computed surface pressure, temperature and experimental data of Hord was obtained. Specifically, a global sensitivity analysis is performed to examine the sensitivity of the turbulent computations to the wall grid resolution, wall treatments and changes in model parameters. A proper near-wall model and grid resolution were suggested. The full cavitation model with default model parameters provided solutions with comparable accuracy to sheet cavitation in liquid hydrogen for the two geometries. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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  • Structural and electrochemical properties of Cl-doped LiFePO(4)/C RID C-4517-2008

    Sun, C. S.   Zhang, Y.   Zhang, X. J.   Zhou, Z.  

    Cl-cloped LiFePO(4)/C cathode materials were synthesized through a carbothermal reduction route, and the microstructure and electrochemical performances were systematically studied. Cl-cloped LiFePO(4)/C cathode materials presented a high discharge capacity of similar to 90mAh g(-1) atthe rateof 20C(3400 mA g(-1)) at room temperature. Electrochemical impedance spectroscopy and cyclic voltamperometry indicated the optimized electrochemical reaction and Li(+) diffusion in the bulk of LiFePO(4) due to Cl-doping. The improved Li(+) diffusion capability is attributed to the microstructure modification of LiFePO(4) via Cl-cloping. (C) 2009 Elsevier B.V. All rights reserved.
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  • Overview of EAST experiments on the development of high-performance steady-state scenario

    Wan, B. N.   Liang, Y. F.   Gong, X. Z.   Li, J. G.   Xiang, N.   Xu, G. S.   Sun, Y. W.   Wang, L.   Qian, J. P.   Liu, H. Q.   Zhang, X. D.   Hu, L. Q.   Hu, J. S.   Liu, F. K.   Hu, C. D.   Zhao, Y. P.   Zeng, L.   Wang, M.   Xu, H. D.   Luo, G. N.   Garofalo, A. M.   Ekedahl, A.   Zhang, L.   Zhang, X. J.   Huang, J.   Ding, B. J.   Zang, Q.   Li, M. H.   Ding, F.   Ding, S. Y.   Lyu, B.   Yu, Y. W.   Zhang, T.   Zhang, Y.   Li, G. Q.   Xia, T. Y.  

    The EAST research program aims to demonstrate steady-state long-pulse advanced high-performance H-mode operations with ITER-like poloidal configuration and RF-dominated heating schemes. Since the 2014 IAEA FEC, EAST has been upgraded with all ITER-relevant auxiliary heating and current drive systems, enabling the investigation of plasma profile control by the coupling/integration of various auxiliary heating combinations. Fully non-inductive steady-state H-mode plasma (H-98,H-y2 > 1.1) was extended over 60 s for the first time with sole RF heating plus good power coupling and impurity and particle control. By means of the 4.6 GHz and 2.45 GHz LHCD systems, H-mode can be obtained and maintained at relatively high density, even up to n(e) similar to 4.5 x 10(19) m(-3), where a current drive effect is still observed. Significant progress has been achieved on EAST, including: (i) demonstration of a steady-state scenario (fully non-inductive with V-loop similar to 0.0 V at high beta(P) similar to 1.8 and high-performance in upper single-null (epsilon similar to 1.6) configuration with the tungsten divertor; (ii) discovery of a stationary H-mode regime with no/small ELM using 4.6 GHz LHCD, and; (iii) achievement of ELM suppression in slowly rotating H-mode plasma with n =3D 1 and 2 RMP compatible with long-pulse operations. The new advances in scenario development provide an integrated solution in achieving long-pulse steady-state operations on EAST.
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  • Influence of Sol-gel Derived Al2O3 Film on the Oxidation Behavior of Ni

    Zhang, X. J.   Li, Q.   Zhao, S. Y.   Gao, C. X.   Wang, S. J.   Sun, L.  

    Al(2)O(3) thin films were deposited on Ni metal by solgel processing from aluminum isopropoxide as the raw material. Isothermal oxidation at temperatures of 1073-1173K was performed to investigate the effect Of Al(2)O(3) thin film on the oxidation behavior of the metal. Results of the oxidation tests show that the oxidation rate of Al(2)O(3) coated samples were reduced due to the applied thin film. The oxide scale formed on the blank samples is completely composed of NiO after 24h oxidation at both temperatures, while the NiO layer is divided into two parts by a very thin alumina scale which is deposited before oxidation.
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  • Laparoscopic clockwise three‐stage radical total proctocolectomy: a video vignette

    Zhang, X. J.   Cao, Y. H.   Li, S.   Liu, C. Y.   Zhao, Y. Z.  

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  • Study on the L-H transition power threshold with RF heating and lithium-wall coating on EAST

    Chen, L.   Xu, G. S.   Nielsen, A. H.   Gao, W.   Duan, Y. M.   Liu, H. Q.   Wang, L.   Li, M. H.   Wang, M.   Zhang, X. J.   Chen, R.   Wang, H. Q.   Sun, Z.   Ding, S. Y.   Yan, N.   Liu, S. C.   Shao, L. M.   Zhang, W.   Hu, G. H.   Li, J.   Zhang, L.   Wan, B. N.  

    The power threshold for low (L) to high (II) confinement mode transition achieved by radio -frequency (RF) heating and lithium -wall coating is investigated experimentally on EAST for two sets of walls: an all carbon wall (C) and molybdenum chamber and a carbon divertor (Mo/C). For both sets of walls, a minimum power threshold Pail- of -0.6 MW was found when the EAST operates in a double null (DN) divertor configuration with intensive lithium -wall coating. When operating in upper single null (USN) or lower single null (LSN), the power threshold depends on the ion V]3 drift direction, The low density dependence of the L -Fl power threshold, namely an increase below a minimum density, was identified in the Mo/C wall for the first time. For the C wall only the single-step L-11 transition with limited injection power is observed whereas also the so-called dithering L -H transition is observed in the Mo/C wall. The dithering behaves distinctively in a USN, DN and LSN configuration, suggesting the divertor pumping capability is an important ingredient in this transition since the internal cryopump is located underneath the lower divertor. Depending on the chosen divertor configuration, the power across the separatrix P1 increases with neutral density near the lower X -point in EAST with the Mo/C. wall, consistent with previous results in the C wall (Xu et al 2011 Nucl. Fusion 51 072001). These findings suggest that the edge neutral density, the ion VB drift as well as the divertor pumping capability play important roles in the L-11 power threshold and transition behaviour.
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  • Identification of target cells for Goose parvovirus infection in the immune system organs

    ZHU, L. Q.   DING, X. Y.   TAO, J.   WANG, J. Y.   ZHANG, X. J.   WANG, X. B.   HU, Y.   LI, H. F.   CHEN, K. W.   ZHU, G. Q.  

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  • Improvement in the Oxidation Resistance of Ti-6Al-4V Alloy by Sol-gel Derived Al2O3 Film

    Zhang, X. J.   Ren, B.Y.   Sheng, Y.G.   Tsubaki, N.  

    Alumina coating derived by sol-gel processing was deposited on Ti-6Al-4V alloy by dip-coating technique. Isothermal oxidation and cyclic oxidation at 873 K and 973 K in static air of the coated specimens with different thickness alumina coating and uncoated ones were performed to investigate the effect of the alumina coating on the oxidation behavior of the Ti-6Al-4V alloy by thermogravimetry, SEM and XRD. The present film exhibited a beneficial effect on the cyclic oxidation resistance of the alloy in air. The optimal thickness of the applied coating on the present alloy was determined in terms of the relationship between the average parabolic rate constants of isothermal oxidation and the coating thickness. Severe spallation and stratification of the scales were observed on the blank specimens, but not on the coated ones. The formation of rutile titania layer beneath and above the alumina film indicated that the growth of the multilayered and mixed oxide scales was dominated by both outward diffusion of metal and inward diffusion of oxygen. The possible mechanism of the thin film on the oxidation behavior of the alloy was discussed.
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  • Systemic lupus erythematosus: a genetic epidemiology study of 695 patients from China

    Wang, J.   Yang, S.   Chen, J. J.   Zhou, S. M.   He, S. M.   Liang, Y. H.   Meng, W.   Yan, X. F.   Liu, J. J.   Ye, D. Q.   Zhang, X. J.  

    Our purpose was to explore potential genetic models for systemic lupus erythematosus (SLE) and analyze genetic epidemiologic characteristics of SLE in a Chinese population. Data for 695 patients with SLE were obtained by using a uniform questionnaire. Patients, clinical characteristics and their family history were analyzed using software. A complex segregation analysis was conducted to propose potential genetic models for SLE. The mean +/- SD age of onset were 30.2 +/- 10.5 years and mean time to progression to SLE was 32.5 +/- 44.4 months. The most frequent initial manifestations were malar rash (61.3%). During the evolution of the disease, the main clinical features were arthritis in 73.6% of our patients, followed by malar rash (68.1%), and renal involvement (56.7%). As the first symptom, the late-onset group (onset of disease beyond the age of 50 years) less often showed malar rash (45% vs. 63.4% in the early-onset group; p = 0.001). There were no significant differences in the other cumulative clinical symptoms between late-onset and early-onset group, except for a lower prevalence of malar rash, photosensitivity and alopecia and a higher prevalence of mucosal ulcers in the late-onset group. A positive family history of SLE was obtained in 50 patients (7.2%). There were no statistical differences in clinical characteristics between familial SLE and sporadic SLE patients. The heritability of SLE was 43.6%, the genetic model of SLE could be polygenetic model and major gene mode is the best fitted one. SLE could be a multifactorial disease with polygenetic model.
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  • Moisture transport and adsorption on silica gel-calcium chloride composite adsorbents

    Zhang, X. J.   Qu, L. M.  

    A measurement of moisture uptake curves in silica gel-calcium composite adsorbents is performed by using the thermal gravimetrical method in a relative vapor pressure range from 0.5 to 0.9 at different temperature levels of 25, 35 and 45 degrees C, respectively. Also, dynamic adsorption curves individually corresponding to the temperature and relative pressure conditions of (25 degrees C, 0.7), (35 degrees C, 0.7) and (35 degrees C, 0.5) have been measured. This experimental study shows that the sorption rate is highest for non-impregnated macroporous silica gel; however, the same silica gel impregnated with calcium chloride has a much greater final water loading. This confirms that composite adsorbents result in a better adsorption performance compared with non-impregnated silica gel, leading to a trade off in finalizing the content of CaCl2 in the composite. Through theoretical analysis on the experimental data, it is found that the saturated adsorption data can be well fitted by the FHH model and the dynamic adsorption data well fitted by the Crank diffusion model, simultaneously yielding the effective solid side mass diffusivities. A comparison with these obtained diffusion coefficients further supports that the mass diffusivity in the composite adsorbent also increases with an increase in temperature, as well as in humidity, but drastically decreases due to the presence of salt inside the matrix pores compared with the non-impregnated host matrix. (c) 2006 Elsevier Ltd. All rights reserved.
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  • Double network self-healing graphene hydrogel by two step method for anticancer drug delivery

    Chen, P.   Wang, X.   Wang, G. Y.   Duo, Y. R.   Zhang, X. Y.   Hu, X. H.   Zhang, X. J.  

    Graphene based materials have showed potential ability to deliver drug. Many research focused on graphene based nanomaterials. Three-dimension graphene hydrogel with good mechanical and electrical properties occurred in recent researches. Based on this, we developed a self-healing graphene hydrogel to deliver anticancer drug by two step method. beta-CD functional graphene hydrogel was first synthesised by hydrothermal reduction. Then double network graphene hydrogel was obtained by polymerisation of N,N-dimethylacrylamide (DMAA) in graphene hydrogel. Beside self-healing property, the double network graphene hydrogel showed potential capacity to deliver anticancer.
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  • Abnormal Behavior of Oxidation Kinetics for Ni-10Cr-10Al Alloy at 1273 and 1373 Κ

    Zhang, X. J.   Gao, C. X.   Wang, S. J.   Sun, L.   Tian, S.  

    The oxidation of Ni-100-10Al alloy was studied under oxygen atmosphere of 105 Pa at 1273 and 1373 K. An exclusive external alumina scale formed at both temperatures. The abnormal behavior of oxidation kinetics is observed. The oxidation kinetics of Ni-10Cr-10Al alloy (in at.%) at both temperatures is composed of different parabolic plots and the initial oxidation rate of Ni-100-10Al alloy at 1373 K is greater than that at 1273 K, while the final oxidation rate at 1373 K is much slower than the 1273 K case. The abnormal behavior of oxidation kinetics of Ni-100-10Al alloy could be attributed to the faster phase transformation of alumina formed during oxidation at 1373 K.
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  • The effect of Cr on the oxidation of Ni-10 at% Al in 1 atm O-2 at 900-1000 degrees C

    Zhang, X. J.   Wang, S. Y.   Gesmundo, F.   Niu, Y.  

    The oxidation of three Ni - xCr - 10Al alloys with a constant Al content of 10 at% and containing 3, 5, and 10 at% Cr was investigated at 900 - 1000 degrees C in 1 atm of pure oxygen and compared to the behavior of Ni - 10Al. At both temperatures, an external NiO scale overlying a zone of internal-oxide precipitates formed on Ni - 10Al and Ni - 3Cr - 10Al: in addition, a discontinuous Al2O3 layer formed at the front of the internal oxidation for Ni - 3Cr - 10Al. An exclusive external scale of Al2O3 formed at most places on Ni - 5Cr - 10Al at 900 degrees C, while, at some sites, the same alloy formed an outer NiO layer overlying an internal oxidation zone. The scales formed on Ni - 5Cr - 10Al at 1000 degrees C were complex, but eventually a protective Al2O3 layer developed either at the alloy surface or beneath a region containing a mixture of different oxides. Finally, an exclusive external Al2O3 layer formed on Ni - 10Cr - 10Al at both temperatures. Thus, the addition of sufficient chromium to Ni - 10Al produced a classical third-element effect, inducing the transition between internal and external oxidation of aluminum under a constant Al content. A possible mechanism for the effect of chromium on the oxidation of Ni - 10Al is discussed on the basis of an extension to ternary alloys of a criterion first proposed by Wagner for the transition between internal and external oxidation of the most-reactive component in binary alloys.
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