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Search Results: 1 - 10 of 341910 matches for " Fu S "
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Experimental Study of Induced Polarization Effect in Unconventional Reservoir Rocks  [PDF]
Vladimir Burtman, Haiyan Fu, Michael S. Zhdanov
Geomaterials (GM) , 2014, DOI: 10.4236/gm.2014.44012
Abstract: Unconventional hydrocarbon reserves substantially surpass those of conventional resources and therefore are extremely economically attractive. However, exploration and production of uncon-ventional reserves is challenging. This paper demonstrates that one can observe significant induced polarization effects in shale reservoir rocks, which can be used in exploration for unconventional reserves. The generalized effective-medium theory of induced polarization (GEMTIP) was used to model the complex resistivity of shale rocks. We demonstrate that GEMTIP modeling provides an evaluation of mineral composition and volume fractions in rock samples. We have conducted spectral induced polarization (IP) measurements using different types of shale rocks to test the feasibility of the IP method and GEMTIP modeling for studying unconventional hydrocarbon (HC) reservoir rocks.
Model for FeSi, a strongly correlated insulator
C. Fu,S. Doniach
Physics , 1994, DOI: 10.1103/PhysRevB.51.17439
Abstract: Revised to reflect the differences between the second order perturbation theory method developed by Scheitzer and Czycholl, and followed by us, and the iterated perturbation theory (IPT)of Georges and Kotliar, et al. Because of our domain of interest, this does not materially change our conclusions, but it is important to realize that the method used here fails in the limit of large $U$, where IPT has had good results.
Evaluation of gene importance in microarray data based upon probability of selection
Li M Fu, Casey S Fu-Liu
BMC Bioinformatics , 2005, DOI: 10.1186/1471-2105-6-67
Abstract: Here we present a model for probability analysis of selected genes in order to determine their importance. Our contribution is that we show how to derive the P value of each selected gene in multiple gene selection trials based on different combinations of data samples and how to conduct a reliability analysis accordingly. The importance of a gene is indicated by its associated P value in that a smaller value implies higher information content from information theory. On the microarray data concerning the subtype classification of small round blue cell tumors, we demonstrate that the method is capable of finding the smallest set of genes (19 genes) with optimal classification performance, compared with results reported in the literature.In classifier design based on microarray data, the probability value derived from gene selection based on multiple combinations of data samples enables an effective mechanism for reducing the tendency of fitting local data particularities.Based on the concept of simultaneously studying the expression of a large number of genes, a DNA microarray is a chip on which numerous probes are placed for hybridization with a tissue sample. The DNA microarray has recently emerged as a powerful tool in molecular biology research, offering high throughput analysis of gene expression on a genomic scale. However, biological complexity encoded by a deluge of microarray data is being translated into all sorts of computational, statistical or mathematical problems.Driven by the growing genomic technology, molecular medicine has become a rapidly advancing field. An important research topic is to identify disease-related gene expression patterns based on microarray analysis. In one approach, genes are selected for constructing a clinically useful classifier for disease diagnosis. The genes thus selected often shed light on the fundamental molecular mechanisms of the disease [1]. As addressed in several research works [1-5], the problem of gene selection
The gene expression data of Mycobacterium tuberculosis based on Affymetrix gene chips provide insight into regulatory and hypothetical genes
Li M Fu, Casey S Fu-Liu
BMC Microbiology , 2007, DOI: 10.1186/1471-2180-7-37
Abstract: We conducted a functional-genomics study using the high-resolution Affymetrix oligonucleotide GeneChip. Approximately one-half of the genes were found to be always expressed, including more than 100 predicted conserved hypotheticals, in the genome of M. tuberculosis during the log phase of in vitro growth. The gene expression profiles were analyzed and visualized through cluster analysis to epitomize the full details of genomic behavior. Broad patterns derived from genome-wide expression experiments in this study have provided insight into the interrelationships among genes in the basic cellular processes of M. tuberculosis.Our results have confirmed several known gene clusters in energy production, information pathways, and lipid metabolism, and also hinted at potential roles of hypothetical and regulatory proteins.Knowledge about the genome sequence of Mycobacterium tuberculosis [1] has contributed to recent advancement in understanding the biology of this organism and its clinical relevance. Concurrent with this development, a high-throughput genome-wide gene expression analysis device in the form of microarrays has rapidly emerged as a seemingly indispensable tool for studying genomics in the modern era. These developments have brought about the revolutionary conception of new prophylactic and therapeutic interventions in the genomic perspective. Its significance should be clear, as tuberculosis is still causing millions of deaths in the world.DNA microarrays have been applied to analyze M. tuberculosis. The first type of application focuses on genotyping, for example, species identification [2,3] and detection of drug-resistant mutants [4,5]. The second type of application seeks to explore altered gene expression and understand biological pathways in terms of up-regulated and down-regulated genes in certain conditions of interest, such as drug challenge [6], hypoxia [7], starvation [8], high temperature [9], and in vivo [10]. However, existing applications do n
Research on the High-Tech Enterprise Performance Index System  [PDF]
Lan Fu, Rong Fu
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.23008
Abstract:

The purpose of this essay is to design a framework of a performance system which is subject to the characteristics of China high-tech enterprises. It is based on analyzing the principles and significance of the performance system of high-tech enterprises. The framework will promote the standardization management of high-tech enterprises of China.

Corrigendum to "A novel downscaling technique for the linkage of global and regional air quality modeling" published in Atmos. Chem. Phys., 9, 9169–9185, 2009
Y. F. Lam ,J. S. Fu
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2010,
Abstract: Recently, downscaling global atmospheric model outputs (GCTM) for the USEPA Community Multiscale Air Quality (CMAQ) Initial (IC) and Boundary Conditions (BC) have become practical because of the rapid growth of computational technologies that allow global simulations to be completed within a reasonable time. The traditional method of generating IC/BC by profile data has lost its advocates due to the weakness of the limited horizontal and vertical variations found on the gridded boundary layers. Theoretically, high quality GCTM IC/BC should yield a better result in CMAQ. Unfortunately, several researchers have found that the outputs from GCTM IC/BC are not necessarily better than profile IC/BC due to the excessive transport of O3 aloft in GCTM IC/BC. In this paper, we intend to investigate the effects of using profile IC/BC and global atmospheric model data. In addition, we are suggesting a novel approach to resolve the existing issue in downscaling. In the study, we utilized the GEOS-Chem model outputs to generate time-varied and layer-varied IC/BC for year 2002 with the implementation of tropopause determining algorithm in the downscaling process (i.e., based on chemical (O3) tropopause definition). The comparison between the implemented tropopause approach and the profile IC/BC approach is performed to demonstrate improvement of considering tropopause. It is observed that without using tropopause information in the downscaling process, unrealistic O3 concentrations are created at the upper layers of IC/BC. This phenomenon has caused over-prediction of surface O3 in CMAQ. In addition, the amount of over-prediction is greatly affected by temperature and latitudinal location of the study domain. With the implementation of the algorithm, we have successfully resolved the incompatibility issues in the vertical layer structure between global and regional chemistry models to yield better surface O3 predictions than profile IC/BC for both summer and winter conditions. At the same time, it improved the vertical O3 distribution of CMAQ outputs. It is strongly recommended that the tropopause information should be incorporated into any two-way coupled global and regional models, where the tropospheric regional model is used, to solve the vertical incompatibility that exists between global and regional models. We have discovered that the previously published paper was not the latest version of the manuscript we intended to use. Some corrections made during the second ACPD reviewing process were not incorporated in the text. As a result, the figure numbers (i.e., figure number below the graph) were not referenced correctly in the manuscript. Therefore, we have decided to re-publish this paper as a corrigendum.
On the seasonal dependence of tropical lower-stratospheric temperature trends
Q. Fu, S. Solomon,P. Lin
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2010,
Abstract: This study examines the seasonality of tropical lower-stratospheric temperature trends using the Microwave Sounding Unit lower-stratospheric channel (T4) for 1980–2008. We present evidence that this seasonality is largely a response to changes in the Brewer-Dobson circulation (BDC) driven by extratropical wave forcing. We show how the tropical T4 trend can be used as an indicator of changes in the BDC, and find that the BDC is strengthening for 1980–2008 in June–November related to the Southern Hemisphere (SH) and in December–February to the Northern Hemisphere (NH). In marked contrast, we find that the BDC is weakening in March–May, apparently because of a weakening of its northern cell. The novel observational evidence on the seasonal dependence of the BDC trends presented in this study has important implications for the understanding of climate change in the stratosphere as well as testing climate model simulations.
Investigation of downscaling techniques for the linkage of global and regional air quality modeling
Y. F. Lam,J. S. Fu
Atmospheric Chemistry and Physics Discussions , 2009,
Abstract: Recent year, downscaling global atmospheric model outputs for the USEPA Community Multiscale Air Quality (CMAQ) Initial (IC) and Boundary Conditions (BC) have become practical because of the rapid growth of computational technologies that allow global simulations can be completed within a reasonable time and have better performance. The traditional method of generating IC/BC by profile data has lost its advocators due to the weakness of the limited horizontal and vertical variations found on the gridded boundary layers. In this paper, we are in effort to investigate the effects of using profile IC/BC and global atmospheric model data. We utilize the GEOS-Chem model outputs to generate time-varied and layer-varied IC/BC for year 2002 using our newly development of tropopause determining algorithm. The purpose of the study is to determine the tropopause effect to the downscaling process. From the results, we have found that without considering tropopause in the downscaling process created unrealistic O3 concentrations in IC/BC at the upper boundary conditions for regional tropospheric model. This phenomenon has caused over-prediction of surface O3 in CMAQ. And it is greatly affected by temperature and latitudinal location. With the implementation of our algorithm, we have successfully resolved the incompatibility issues in the vertical layer structure between global and regions chemistry models to yield better surface O3 predictions than profile IC/BC on both summer and winter conditions. At the same time, it improved the vertical O3 distribution of CMAQ outputs. The algorithm can be applied to a global atmospheric model which performs a reasonable outcome to determine the tropopause.
On the seasonal dependence of tropical lower-stratospheric temperature trends
Q. Fu,S. Solomon,P. Lin
Atmospheric Chemistry and Physics Discussions , 2009,
Abstract: This study examines the seasonality of tropical lower-stratospheric temperature trends using the Microwave Sounding Unit lower-stratospheric channel (T4) for 1979–2007. We present evidence that this seasonality is a response to changes in the Brewer–Dobson circulation (BDC) driven by extratropical wave forcing. We show how the tropical T4 trend can be used as an indicator of the change in the BDC, and find that the BDC is strengthening for 1979–2007 in June–November related to the Southern Hemisphere (SH) and in December–February to the Northern Hemisphere (NH). In marked contrast, we find that the BDC is weakening in March–May, apparently because of a weakening of its northern cell. The novel observational evidence on the seasonal dependence of the BDC trends presented in this study has important implications for the understanding of climate change in the stratosphere as well as testing climate model simulations.
Carbonaceous components, levoglucosan and inorganic ions in tropical aerosols from Tanzania, East Africa: implication for biomass burning contribution to organic aerosols
S. L. Mkoma,K. Kawamura,P. Fu
Atmospheric Chemistry and Physics Discussions , 2012, DOI: 10.5194/acpd-12-28661-2012
Abstract: Atmospheric aerosol samples of PM2.5 and PM10 were collected at a rural site in Tanzania in 2011 during wet and dry seasons and they were analysed for carbonaceous components, levoglucosan and water-soluble inorganic ions. The mean mass concentrations of PM2.5 and PM10 were 28.2±6.4 μg m 3 and 47±8.2 μg m 3 in wet season, and 39.1±9.8 μg m 3 and 61.4±19.2 μg m 3 in dry season, respectively. Total carbon (TC) accounted for 16–19% of the PM2.5 mass and 13–15% of the PM10 mass. On average, 85.9 to 88.7% of TC in PM2.5 and 87.2 to 90.1% in PM10 was organic carbon (OC), of which 67–72% and 63% was found to be water-soluble organic carbon (WSOC) in PM2.5 and PM10, respectively. Water-soluble potassium (K+) and sulphate (SO42 ) in PM2.5 and, sodium (Na+) and SO42 in PM10 were the dominant ionic species. We found, that concentrations of biomass burning tracers (levoglucosan and mannosan) well correlated with non-sea-salt-K+, WSOC and OC in the aerosols from Tanzania, East Africa. Mean contributions of levoglucosan to OC ranged between 3.9–4.2% for PM2.5 and 3.5–3.8% for PM10. This study demonstrates that emissions from biomass- and biofuel-burning activities followed by atmospheric photochemical processes mainly control the air quality in Tanzania.
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