Showing papers by "Xi'an Jiaotong University published in 2007"
TL;DR: In this paper, simultaneous measurements of atmospheric organic and elemental carbon (OC and EC) were taken during winter and summer seasons at 2003 in 14 cities in China, and PM2.5 samples were analyzed for OC and EC by the Interagency Monitoring of Protected Visual Environments (IMPROVE) thermal/optical reflectance protocol.
Abstract: [1] Simultaneous measurements of atmospheric organic and elemental carbon (OC and EC) were taken during winter and summer seasons at 2003 in 14 cities in China. Daily PM2.5 samples were analyzed for OC and EC by the Interagency Monitoring of Protected Visual Environments (IMPROVE) thermal/optical reflectance protocol. Average PM2.5 OC concentrations in the 14 cities were 38.1 μg m−3 and 13.8 μg m−3 for winter and summer periods, and the corresponding EC were 9.9 μg m−3 and 3.6 μg m−3, respectively. OC and EC concentrations had summer minima and winter maxima in all the cities. Carbonaceous matter (CM), the sum of organic matter (OM = 1.6 × OC) and EC, contributed 44.2% to PM2.5 in winter and 38.8% in summer. OC was correlated with EC (R2: 0.56–0.99) in winter, but correlation coefficients were lower in summer (R2: 0.003–0.90). Using OC/EC enrichment factors, the primary OC, secondary OC and EC accounted for 47.5%, 31.7% and 20.8%, respectively, of total carbon in Chinese urban environments. More than two thirds of China's urban carbon is derived from directly emitted particles. Average OC/EC ratios ranged from 2.0 to 4.7 among 14 cities during winter and from 2.1 to 5.9 during summer. OC/EC ratios in this study were consistent with a possible cooling effect of carbonaceous aerosols over China.
992 citations
01 Sep 2007
TL;DR: This Special Issue of International Journal of Computer Mathematics (IJCM) offers a venue to present innovative approaches in computer vision and pattern recognition, which have been changing the authors' everyday life dramatically over the last few years, and aims to provide readers with cutting-edge and topical information for their related research.
Abstract: This Special Issue of International Journal of Computer Mathematics (IJCM) offers a venue to present innovative approaches in computer vision and pattern recognition, which have been changing our e...
697 citations
TL;DR: The relationship between obesity and osteoporosis is reevaluate by accounting for the mechanical loading effects of total body weight on bone mass and the phenotypic correlation between fat mass and fat mass was negative, suggesting increasing fat mass may not have a beneficial effect on bonemass.
Abstract: Context: The relationship between obesity and osteoporosis has been widely studied, and epidemiological evidence shows that obesity is correlated with increased bone mass. Previous analyses, however, did not control for the mechanical loading effects of total body weight on bone mass and may have generated a confounded or even biased relationship between obesity and osteoporosis. Objective: The objective of this study was to reevaluate the relationship between obesity and osteoporosis by accounting for the mechanical loading effects of total body weight on bone mass. Methods: We measured whole body fat mass, lean mass, percentage fat mass, body mass index, and bone mass in two large samples of different ethnicity: 1988 unrelated Chinese subjects and 4489 Caucasian subjects from 512 pedigrees. We first evaluated the Pearson correlations among different phenotypes. We then dissected the phenotypic correlations into genetic and environmental components with bone mass unadjusted or adjusted for body weight. T...
551 citations
TL;DR: It is unclear whether fat has beneficial effects on bone, and it is anticipated that this will be an active and fruitful focus of research in the coming years.
Abstract: It was previously believed that obesity and osteoporosis were two unrelated diseases, but recent studies have shown that both diseases share several common genetic and environmental factors. Body fat mass, a component of body weight, is one of the most important indices of obesity, and a substantial body of evidence indicates that fat mass may have beneficial effects on bone. Contrasting studies, however, suggest that excessive fat mass may not protect against osteoporosis or osteoporotic fracture. Differences in experimental design, sample structure, and even the selection of covariates may account for some of these inconsistent or contradictory results. Despite the lack of a clear consensus regarding the impact of effects of fat on bone, a number of mechanistic explanations have been proposed to support the observed epidemiologic and physiologic associations between fat and bone. The common precursor stem cell that leads to the differentiation of both adipocytes and osteoblasts, as well the secretion of adipocyte-derived hormones that affect bone development, may partially explain these associations. Based on our current state of knowledge, it is unclear whether fat has beneficial effects on bone. We anticipate that this will be an active and fruitful focus of research in the coming years.
462 citations
TL;DR: The proposed method for fault diagnosis based on empirical mode decomposition (EMD), an improved distance evaluation technique and the combination of multiple adaptive neuro-fuzzy inference systems (ANFISs) show that the multiple ANFIS combination can reliably recognise different fault categories and severities.
406 citations
TL;DR: The proposed method is applied to the fault diagnosis of rolling element bearings, and testing results show that the SVMs ensemble can reliably separate different fault conditions and identify the severity of incipient faults, which has a better classification performance compared to the single SVMs.
371 citations
TL;DR: The results suggest that a two-step process of combining dark- and photo-fermentation may increase hydrogen production capacity from biomass and prevent the environmental problems associated with untreated fermentation effluents.
275 citations
TL;DR: The 2006 CHF look-up table is characterized by a significant improvement in accuracy and smoothness, based on a database containing more than 30,000 data points and providing CHF values at 24 pressures, 20 mass fluxes, and 23 qualities, covering the full range of conditions of practical interest.
273 citations
TL;DR: In this paper, the results from systematic experimental and analytical study on biomass gasification in supercritical water in our laboratory are summarized and the development status and future prospect on supercritical Water Gasification is evaluated.
265 citations
TL;DR: In this article, a 3-cylinder port fuel injection engine was adopted to study engine power, torque, fuel economy, emissions including regulated and non-regulated pollutants and cold start performance with the fuel of low fraction methanol in gasoline.
263 citations
21 Aug 2007
TL;DR: In this paper, a review of recent research on air conditioning systems and indoor air quality control for human health is presented, where the problems in the existing research are summarized and further study is suggested on air-conditioning systems and Indoor Air Quality Control for healthy indoor air environment.
Abstract: With the improvement of the living standard, air conditioning has been applied widely. Meanwhile, health problems associated with air-conditioning systems and indoor air quality appear more frequently. In this paper, recent research is reviewed on air-conditioning systems and indoor air quality control for human health. The problems in the existing research are summarized. Further study is suggested on air-conditioning systems and indoor air quality control for healthy indoor air environment.
TL;DR: In this paper, a well-defined dendritic silver nanostructure can be large-scale synthesized in AgNO3 (aqueous) at room temperature, and the nonequilibrium and anisotropic growth at different silver ion concentrations result in controllable morphologies and morphological evolution.
Abstract: In this study, a well-defined dendritic silver nanostructure can be large-scale synthesized in AgNO3 (aqueous) at room temperature. The nonequilibrium and anisotropic growth at different silver ion concentrations result in controllable morphologies and morphological evolution. At high silver ion concentrations, a strong anisotropic growth contributes to a fine single crystalline silver dendrite. As the reaction proceeds, the dendritic structure transforms into a thermodynamically stable hexagonal structure. At a relatively low silver ion concentration, a particle-aggregated fractal pattern can be obtained due to relatively small anisotropy. As the reaction time increases, the transition from polycrystalline aggregates to a single crystal during silver dendritic growth can be observed. An oriented attachment mechanism can be used to explain the structural and morphological evolution of silver nanostructures. Silver nanostructures with various morphologies are expected to have significant potential applicat...
TL;DR: The capacity dimension, information dimension and correlation dimension are applied to classify various fault types and evaluate various fault conditions of rolling element bearing, and the classification performance of each fractal dimension and their combinations are evaluated by using SVMs.
TL;DR: In this article, a new experimental system of biomass gasification in supercritical water was built in SKLMF, and a comprehensive thermodynamic analysis, including chemical equilibrium in the reactor, gas-liquid equilibrium in high-pressure separator, exergy and energy analysis of the whole system, was conducted.
TL;DR: A polymerized film of eriochrome black T (EBT) was prepared on the surface of a glassy carbon (GC) electrode in alkaline solution by cyclic voltammetry (CV).
TL;DR: In this article, an ion exchange method was used to synthesize the biodiesel (fatty acid methyl esters, FAME), which was applied as the ion exchange precursor to incorporate La ion into zeolite beta.
TL;DR: In this article, the authors describe a theoretical analysis of a transcritical CO2 ejector expansion refrigeration cycle (EERC) which uses an ejector as the main expansion device instead of an expansion valve.
TL;DR: In this article, the authors investigated the combustion characteristics of a direct-injection spark-ignited engine fueled with natural gas-hydrogen blends under various ignition timings and lean mixture condition.
TL;DR: New lower and upper approximations are proposed and some important properties in generalized rough set induced by a covering are obtained and compared with ones of Pawlak's rough sets and Bonikowski's covering generalized rough sets.
01 May 2007
TL;DR: This work analyzes a class of large time-stepping methods for the Cahn-Hilliard equation discretized by Fourier spectral method in space and semi-implicit schemes in time and investigates the stability and convergence properties based on an energy approach.
Abstract: In this work, we will analyze a class of large time-stepping methods for the Cahn-Hilliard equation. The equation is discretized by Fourier spectral method in space and semi-implicit schemes in time. For first-order semi-implicit scheme, the stability and convergence properties are investigated based on an energy approach. Here stability means that the decay of energy is preserved. The numerical experiments are used to demonstrate the effectiveness of the large time-stepping approaches.
TL;DR: In this paper, a system consisting of two singlemode cavities spatially separated and connected by an optical fiber and multiple two-level atoms trapped in the cavities is considered, and an ideal quantum state transfer and highly reliable quantum swap, entangling and controlled-Z gates can be deterministically realized between the distant cavities.
Abstract: A system consisting of two single-mode cavities spatially separated and connected by an optical fiber and multiple two-level atoms trapped in the cavities is considered. If the atoms resonantly and collectively interact with the local cavity fields but there is no direct interaction between the atoms, we show that an ideal quantum state transfer and highly reliable quantum swap, entangling, and controlled-Z gates can be deterministically realized between the distant cavities. We find that the operation of state transfer and swap, entangling, and controlled-Z gates can be greatly speeded up as number of the atoms in the cavities increases. We also notice that the effects of spontaneous emission of atoms and photon leakage out of cavity on the quantum processes can also be greatly diminished in the multiatom case.
TL;DR: A new genetic algorithm hybridized with an innovative local search procedure (bottleneck shifting) for the flexible job shop scheduling problem, which provides a closer approximation to real scheduling problems.
TL;DR: In this article, a necessary and sufficient condition on the existence of orthogonal vector-valued wavelets is derived by means of paraunitary vector filter bank theory, and an algorithm for constructing a class of compactly supported OVW wavelet packets is presented.
Abstract: In this paper, vector-valued multiresolution analysis and orthogonal vector-valued wavelets are introduced. The definition for orthogonal vector-valued wavelet packets is proposed. A necessary and sufficient condition on the existence of orthogonal vector-valued wavelets is derived by means of paraunitary vector filter bank theory. An algorithm for constructing a class of compactly supported orthogonal vector-valued wavelets is presented. The properties of the vector-valued wavelet packets are investigated by using operator theory and algebra theory. In particular, it is shown how to construct various orthonormal bases of L2(R, Cs) from the orthogonal vector-valued wavelet packets.
TL;DR: In this article, a direct injection engine operating on various fractions of natural gas-hydrogen blends was investigated and the results showed that the brake effective thermal efficiency increased with the increase of hydrogen fraction at low and medium engine loads and high thermal efficiency was maintained at the high engine load.
TL;DR: In this article, a series of Cd 1 - x Zn x S solid solution photocatalysts were prepared by thermal sulfuration of the corresponding mixed oxide precursors.
TL;DR: In this article, the electrochemical capacitance properties of composite films prepared from electrically conducting polypyrrole (PPy) and single wall carbon nanotubes (SWNTs) have been investigated for supercapacitor application.
TL;DR: This study aims to determine whether the signal of HIF‐1α for inducing prostate cancer cells to undergo EMT might possibly pass through the Wnt/β‐catenin pathway.
Abstract: Objectives Epithelial-mesenchymal transition (EMT) is an important process in tumor development, and several studies suggest that the Wnt/beta-catenin signal pathway may play an important role in EMT. However, there is no direct evidence showing that the Wnt/beta-catenin pathway actually determines the EMT induced by an exogenous signal. Our previous research has successfully proved that overexpression of hypoxia-inducible factor-1alpha (HIF-1alpha) could induce EMT in LNCaP cells, but not in PC-3. The present study aims to determine whether the signal of HIF-1alpha for inducing prostate cancer cells to undergo EMT might possibly pass through the Wnt/beta-catenin pathway. Methods Epithelial-mesenchymal transition associated proteins were detected in several human prostate carcinoma cell lines by Western blot, and then we distinguished the EMT positive cell lines from the EMT negative cell lines. Furthermore, we evaluated the possible correlation between potency of invasiveness and proliferation among these cell lines with different characteristics of EMT using Matrigel transwell and thiazolyl blue tetrazolium bromide (MTT) assays. Finally, the different expression of some critical proteins and genes in Wnt/beta-catenin signaling pathway were analyzed by Western blot and reverse transcription-polymerase chain reaction (RT-PCR) in these cells with different characteristics of EMT. Results Among several prostate cancer cell lines, PC-3, LNCaP and PC-3/HIF-1alpha are EMT negative cell lines, whereas LNCaP/HIF-1alpha and IA8 have undergone the EMT process. EMT positive cells (LNCaP/HIF-1alpha and IA8) exhibit much stronger potency of invasiveness and proliferation than those of PC-3 and LNCaP, which belong to EMT negative cells. Interestingly, although PC-3/HIF-1alpha had not completed the EMT process, it still displayed stronger potency of invasion and proliferation, resembling EMT positive cells. The protein expression level of total glycogensynthase kinase 3beta (GSK-3beta) and phospho-GSK-3beta in LNCaP/HIF-1alpha, IA8 and PC-3/HIF-1alpha cells significantly decreased; however, the relative ratios of p-GSK3beta/t-GSK3beta in LNCaP/HIF-1alpha, IA8 and PC-3/HIF-1alpha cells were significantly higher than PC-3 and LNCaP. Consistently, beta-catenin protein expression increased in LNCaP/HIF-1alpha and IA8 cells, but not in PC-3/HIF-1alpha; RT-PCR confirmed these results, except for the enhanced transcription activity of beta-catenin mRNA in PC-3/HIF-1alpha. Conclusion Our data suggests that activation of the Wnt/beta-catenin signaling pathway correlates with the characteristic of EMT and potency of invasiveness and proliferation. This may be the critical factor that directly controls the process of EMT induced by HIF-1alpha in prostate cancer cells.
TL;DR: In this paper, the electrostatic coupling between single-walled carbon nanotubes (SWCNT) and planar gate electrodes in thin-film transistors (TFTs) is analyzed both in the quantum limit with an analytical model and in the classical limit with finite element modeling.
Abstract: The electrostatic coupling between singled-walled carbon nanotube (SWCNT) networks/arrays and planar gate electrodes in thin-film transistors (TFTs) is analyzed both in the quantum limit with an analytical model and in the classical limit with finite-element modeling. The computed capacitance depends on both the thickness of the gate dielectric and the average spacing between the tubes, with some dependence on the distribution of these spacings. Experiments on transistors that use submonolayer, random networks of SWCNTs verify certain aspects of these calculations. The results are important for the development of networks or arrays of nanotubes as active layers in TFTs and other electronic devices.
TL;DR: In the study, a similarity degree based algorithm is proposed to aggregate the objective information about ERP systems from some external professional organizations, which may be expressed by different linguistic term sets.
TL;DR: In this paper, an analytical treatment is presented for the propagation of harmonic waves in magneto-electro-elastic multilayered plates, where the general anisotropic and three-phase coupled constitutive equations are used.