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Search Results: 1 - 10 of 104178 matches for " Shibin Zhang "
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Daqing Oilfield Liquid Phase Underbalanced Drilling Improving Drilling Speed Evaluation Method  [PDF]
Shibin Li, Penghao Wang, Ligang Zhang
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2015, DOI: 10.4236/jmmce.2015.31005
Abstract: Factors affecting the drilling speed are very complex, such as formation factor (layers lithology, depth, porosity and reservoir pressure), fluid density, drilling parameters (bit pressure and speed), drill types, etc. Although liquid phase underbalanced drilling technology is to increase the penetration rate and shorten the drilling cycle, there is no evaluation model currently, so we cannot evaluate which factors can have a greater impact on speed. Based on the establishment of equivalent density and improvement of ROP (Rate of Penetration) calculation model, this paper is about the application of underbalanced drilling technology to improve drilling speed multiple sizes.
Testing the Equality Hypothesis on a Cross-Covariance Matrix  [PDF]
Xiaomei Chen, Shibin Zhang
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1105584
Abstract:
This paper is concerned about testing whether a cross-covariance matrix deviates from a pre-assigned one or not. For this purpose, a new test statistic is constructed based on the Frobenius norm of the difference between the sample cross-covariance matrix and the pre-assigned matrix. The test is implemented by applying the parametric bootstrap scheme. We conduct a simulation study to examine the performance of the test and compare it with other competitive tests. As multiple simulation examples show, our empirical powers are clearly superior to others in detecting any deviation of the cross-covariance from the pre-assigned matrix. In addition, the proposed test is insensitive to non-cross-covariance elements in the covariance matrix. As an illustration, we also investigate its performance in testing pairwise time-reversibility.
Analysis on the Effect of the Nonlinear Resistance on the Locomotive Operating Overvoltages  [PDF]
Zhengqing Han, Donglin Zhang, Yuning Wu, Shibin Gao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B236
Abstract:

With the application of the articulated phase insulator, and the speed of electric locomotive rising, it is inevitable for the electric locomotive to adopt the technology automatic passing through the electric phase separation. However, when the locomotive passes the electric phase separation, a variety of overvoltages will be generated, such as the cut-off overvoltage and the closing overvoltage. In this paper, the causes of the two overvoltages above are analyzed theoretically and simulated in Simulink. Then this paper discusses the suppression effects on the cut-off overvoltage and the closing overvoltage by paralleling the nonlinear resistance and the main breaker, or parallelling the nonlinear resistance and the locomotive transformer. The simulation results show that parallelling the nonlinear resistance and the locomotive transformer has suppressive effects on the two overvoltages mentioned above.

Effect of Oxygen Concentration and Annealing Theatment on the Optical Properties of the Transparent Conductive CdIn_2O_4 Thin Films
Bin WU,Changyong CHEN,Shibin ZHANG,

材料科学技术学报 , 1998,
Abstract: Transparent conductive cadmium indium oxide films (CdIn2O4) were prepared by r.f. reactive sputtering from Cd-In alloy targets under an Ar-O2 atmosphere. Electrical conductivity of the order of 105Ω-1.m-1 and the optical transmission as high as 94% are easily attained by postdeposition annealing treatment. The effects of oxygen concentration in the reactive gas mixture and post-deposition annealing treatment on the optical transmittance as well as optical parameters, such as refractive index (n), extinction coefficient (k), real part (ε') and imaginary part (ε") of the dielectric constant, were studied in the visible and near-infrared region. The highfrequency dielectric constant ε∞ the plasma frequency ωP, and the conduction band effective mass mc of different samples were also investigated
Large-scale Synthesis of β-SiC Nanochains and Their Raman/Photoluminescence Properties
Meng Alan,Zhang Meng,Gao Weidong,Sun Shibin
Nanoscale Research Letters , 2011,
Abstract: Although the SiC/SiO2 nanochain heterojunction has been synthesized, the chained homogeneous nanostructure of SiC has not been reported before. Herein, the novel β-SiC nanochains are synthesized assisted by the AAO template. The characterized results demonstrate that the nanostructures are constructed by spheres of 25–30 nm and conjoint wires of 15–20 nm in diameters. Raman and photoluminescence measurements are used to explore the unique optical properties. A speed-alternating vapor–solid (SA-VS) growth mechanism is proposed to interpret the formation of this typical nanochains. The achieved nanochains enrich the species of one-dimensional (1D) nanostructures and may hold great potential applications in nanotechnology.
Effect of Low Phosphorus Stress on Endogenous Hormone Levels of Different Maize Genotypes in Seedling Stage
Yaou Shen,Yongzhong Zhang,Haijian Lin,Shibin Gao
Journal of Biological Sciences , 2012,
Abstract: The study was aimed at revealing the effect of low phosphorus stress on endogenous hormone levels of maize lines and displaying the different regulars of hormone change under phosphorus starvation between high P-efficient lines and low P-efficient lines, as well as providing the theoretical foundation for identifying high P-efficient lines at the seedling stage. In the present research, two high P-efficient inbred lines of maize 178 and 129, two low P-efficient ones 9782 and 202, with the F1 generation of 178 and 9782 were conducted to assay for the dynamic change of endogenous hormones in immature leaves and roots under low-phosphorus treatment by the method of solution culture, sand culture and field cultivation. As a result, all of the hormones except ABA were observed more abundant in the high P-efficient lines and F1 hybrid than the low P-efficient lines. The contents of zeatin in leaves and roots decreased significantly by the stress of phosphorus starvation under all of the environments, contrarily the contents of gibberellic acid (GA3), Indol-3-acetic acid (IAA) and Abscisic Acid (ABA) increased after suffering the low-P stress. In addition, the change ranges of GA3 and IAA were greater in high P-efficient lines 178, 129 and the F1 hybrid than in low P-efficient 9782 line and 202 line, whereas it is the opposite case for Zeatin (ZT) and Abscisic Acid (ABA) contents. However, no significant difference of every hormone change was observed between the two high P-efficient inbred lines as well as the two low P-efficient ones. Which indicated that the distinction of the hormone sensibilities to phosphorus starvation were just specifically present among the lines with different P-availability and can be considered as an important reference basis for identifying phosphorus efficiency of maize lines. Each of the hormones in the F1 hybrid always displayed the highest or the lowest values among all the lines, indicating the heterobeltiosis of F1 generation in response to low starvation. So the method of cross breeding can be considered to applied to breeding higher P-efficient lines of maize.
Analysis of alternative signaling pathways of endoderm induction of human embryonic stem cells identifies context specific differences
Shibin Mathew, Maria Jaramillo, Xinan Zhang, Li Zhang, Alejandro Soto-Gutiérrez, Ipsita Banerjee
BMC Systems Biology , 2012, DOI: 10.1186/1752-0509-6-154
Abstract: hESCs were induced towards endoderm using activin A and 4 different growth factors (FGF2 (F), BMP4 (B), PI3KI (P), and WNT3A (W)) and their combinations thereof, resulting in 15 total experimental conditions. At the end of differentiation each condition was analyzed by qRT-PCR for 12 relevant endoderm related transcription factors (TFs). As a first approach, we used hierarchical clustering to identify which growth factor combinations favor up-regulation of different genes. In the next step we identified sets of co-regulated transcription factors using a biclustering algorithm. The high variability of experimental data was addressed by integrating the biclustering formulation with bootstrap re-sampling to identify robust networks of co-regulated transcription factors. Our results show that the transition from early to late endoderm is favored by FGF2 as well as WNT3A treatments under high activin. However, induction of late endoderm markers is relatively favored by WNT3A under high activin.Use of FGF2, WNT3A or PI3K inhibition with high activin A may serve well in definitive endoderm induction followed by WNT3A specific signaling to direct the definitive endoderm into late endodermal lineages. Other combinations, though still feasible for endoderm induction, appear less promising for pancreatic endoderm specification in our experiments.Embryonic stem cells have been shown to have tremendous impact in the field of regenerative medicine because of its potential to differentiate to multiple cell types of interest. Efficient harvesting of this potential requires careful development of protocols to evolve the cells through specific signaling pathways which will induce desired lineages and properties in the differentiated phenotypes. Our primary interest lies in differentiation of human embryonic stem cells (hESCs) to insulin producing β-cells of the pancreas as a cellular transplantation strategy for diabetes mellitus. The first and perhaps the most important step in diff
Validation of Potential Reference Genes for qPCR in Maize across Abiotic Stresses, Hormone Treatments, and Tissue Types
Yueai Lin, Chenlu Zhang, Hai Lan, Shibin Gao, Hailan Liu, Jian Liu, Moju Cao, Guangtang Pan, Tingzhao Rong, Suzhi Zhang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095445
Abstract: The reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a powerful and widely used technique for the measurement of gene expression. Reference genes, which serve as endogenous controls ensure that the results are accurate and reproducible, are vital for data normalization. To bolster the literature on reference gene selection in maize, ten candidate reference genes, including eight traditionally used internal control genes and two potential candidate genes from our microarray datasets, were evaluated for expression level in maize across abiotic stresses (cold, heat, salinity, and PEG), phytohormone treatments (abscisic acid, salicylic acid, jasmonic acid, ethylene, and gibberellins), and different tissue types. Three analytical software packages, geNorm, NormFinder, and Bestkeeper, were used to assess the stability of reference gene expression. The results revealed that elongation factor 1 alpha (EF1α), tubulin beta (β-TUB), cyclophilin (CYP), and eukaryotic initiation factor 4A (EIF4A) were the most reliable reference genes for overall gene expression normalization in maize, while GRP (Glycine-rich RNA-binding protein), GLU1(beta-glucosidase), and UBQ9 (ubiquitin 9) were the least stable and most unsuitable genes. In addition, the suitability of EF1α, β-TUB, and their combination as reference genes was confirmed by validating the expression of WRKY50 in various samples. The current study indicates the appropriate reference genes for the urgent requirement of gene expression normalization in maize across certain abiotic stresses, hormones, and tissue types.
Trichostatin A Selectively Suppresses the Cold-Induced Transcription of the ZmDREB1 Gene in Maize
Yong Hu,Lu Zhang,Lin Zhao,Jun Li,Shibin He,Kun Zhou,Fei Yang,Min Huang,Li Jiang,Lijia Li
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0022132
Abstract: Post-translational modifications of histone proteins play a crucial role in responding to environmental stresses. Histone deacetylases (HDACs) catalyze the removal of an acetyl group from histones and are generally believed to be a transcriptional repressor. In this paper, we report that cold treatment highly induces the up-regulation of HDACs, leading to global deacetylation of histones H3 and H4. Treatment of maize with the HDAC inhibitor trichostatin A (TSA) under cold stress conditions strongly inhibits induction of the maize cold-responsive genes ZmDREB1 and ZmCOR413. However, up-regulation of the ZmICE1 gene in response to cold stress is less affected. The expression of drought and salt induced genes, ZmDBF1 and rab17, is almost unaffected by TSA treatment. Thus, these observations show that HDACs may selectively activate transcription. The time course of TSA effects on the expression of ZmDREB1 and ZmCOR413 genes indicates that HDACs appear to directly activate the ZmDREB1 gene, which in turn modulates ZmCOR413 expression. After cold treatment, histone hyperacetylation and DNA demethylation occurs in the ICE1 binding region, accompanied by an increase in accessibility to micrococcal nuclease (MNase). The two regions adjacent to the ICE1 binding site remain hypoacetylated and methylated. However, during cold acclimation, TSA treatment increases the acetylation status and accessibility of MNase and decreases DNA methylation at these two regions. However, TSA treatment does not affect histone hyperacetylation and DNA methylation levels at the ICE1 binding regions of the ZmDREB1 gene. Altogether, our findings indicate that HDACs positively regulate the expression of the cold-induced ZmDREB1 gene through histone modification and chromatin conformational changes and that this activation is both gene and site selective.
A High-Through Technique to Measure DNA Methylation
Zhiming Zhang, Jian Gao, Cheng Qin, Li Liu, Haijian Lin, Yaou Shen, Shibin Gao, Maojun Zhao, Haiping Ding and Guangtang Pan
Genetics & Epigenetics , 2012, DOI: 10.4137/GEG.S5035
Abstract: MethyLight is a sodium-bisulfite-dependent, quantitative, fluorescence-based, real-time PCR strategy that is used to detect and quantify DNA methylation in genomic DNA. High-throughput MethyLight allows the rapid and sensitive detection of very low frequencies of hypermethylated alleles in populations of alternated individuals. The high sensitivity and specificity of MethyLight can be applied not only to make it uniquely suited disease clinical but also quantitatively assessed of these low-frequency methylation events. Owing to its full of advantages of simple procedure, high efficiency and high sensitivity, MethyLight provides a powerful approach for clinical examination, Gene expression analysis, SNP analysis and allele analysis. Coupled with other techniques, MethyLight can be used immediately in identifying allelic alterations in genes exhibiting expressions correlating with phenotypes, Locating an allelic series of induced point mutations in genes of interest. The development of this technique should considerably enhance our ability to rapidly and accurately generate epigenetic profiles of samples.
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