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Search Results: 1 - 10 of 29474 matches for " Zicong Jian "
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Low-Temperature Reverse Microemulsion Synthesis, Characterization, and Photocatalytic Performance of Nanocrystalline Titanium Dioxide
Zhang Liu,Zicong Jian,Jianzhang Fang,Xiaoxin Xu,Ximiao Zhu,Shuxing Wu
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/702503
Abstract: Nanocrystalline titanium dioxide (TiO2) was synthesized in microemulsions by using cetyltrimethylammonium bromide (CTAB) as surfactant. In order to investigate the crystal transformation and photoactivity at low temperature, the as-prepared precipitates were aged at 65°C or calcined at various temperatures. Analyses using powder X-ray diffraction (XRD) and Fourier transform infrared microscopy (FT-IR) showed that precursors without aging or calcination were noncrystal and adsorbed by surfactant. After aging for 6 h, the amorphous TiO2 began to change into anatase. The obtained catalysts, which were synthesized in microemulsions with weight ratios of n-hexanol/CTAB/water as 6 : 3 : 1 and calcined at 500°C, presented the highest photocatalytic degradation rate on methyl orange (MO), while the catalysts, which were aged at 65°C for 90 h, also exhibited an outstanding photocatalytic performance and a little higher than that of the commercial titania photocatalyst Degussa P25.
Sequence-Dependent Effects on the Properties of Semiflexible Biopolymers
Zicong Zhou,Bela Joos
Physics , 2008, DOI: 10.1103/PhysRevE.77.061906
Abstract: Using path integral technique, we show exactly that for a semiflexible biopolymer in constant extension ensemble, no matter how long the polymer and how large the external force, the effects of short range correlations in the sequence-dependent spontaneous curvatures and torsions can be incorporated into a model with well-defined mean spontaneous curvature and torsion as well as a renormalized persistence length. Moreover, for a long biopolymer with large mean persistence length, the sequence-dependent persistence lengths can be replaced by their mean. However, for a short biopolymer or for a biopolymer with small persistence lengths, inhomogeneity in persistence lengths tends to make physical observables very sensitive to details and therefore less predictable.
Disordered, stretched, and semiflexible biopolymers in two dimensions
Zicong Zhou,Bela Joos
Physics , 2009, DOI: 10.1103/PhysRevE.80.061911
Abstract: We study the effects of intrinsic sequence-dependent curvature for a two dimensional semiflexible biopolymer with short-range correlation in intrinsic curvatures. We show exactly that when not subjected to any external force, such a system is equivalent to a system with a well-defined intrinsic curvature and a proper renormalized persistence length. We find the exact expression for the distribution function of the equivalent system. However, we show that such an equivalent system does not always exist for the polymer subjected to an external force. We find that under an external force, the effect of sequence-disorder depends upon the averaging order, the degree of disorder, and the experimental conditions, such as the boundary conditions. Furthermore, a short to moderate length biopolymer may be much softer or has a smaller apparent persistent length than what would be expected from the "equivalent system". Moreover, under a strong stretching force and for a long biopolymer, the sequence-disorder is immaterial for elasticity. Finally, the effect of sequence-disorder may depend upon the quantity considered.
A possible generalized form of Jarzynski equality
Z. C. Tu,Zicong Zhou
Physics , 2005, DOI: 10.1088/0253-6102/46/5/024
Abstract: The crucial condition in the derivation of the Jarzynski equality (JE) from the fluctuation theorem is that the time integral of the phase space contraction factor can be exactly expressed as the entropy production resulting from the heat absorbed by the system from the thermal bath. For the system violating this condition, a more general form of JE may exist. This existence is verified by three \textit{Gedanken} experiments and numerical simulations, and may be confirmed by the real experiment in the nanoscale.
Automated Dynamic Cellular Analysis in Time-Lapse Microscopy  [PDF]
Shuntaro Aotake, Chamidu Atupelage, Zicong Zhang, Kota Aoki, Hiroshi Nagahashi, Daisuke Kiga
Journal of Biosciences and Medicines (JBM) , 2016, DOI: 10.4236/jbm.2016.43008
Abstract:

Analysis of cellular behavior is significant for studying cell cycle and detecting anti-cancer drugs. It is a very difficult task for image processing to isolate individual cells in confocal microscopic images of non-stained live cell cultures. Because these images do not have adequate textural variations. Manual cell segmentation requires massive labor and is a time consuming process. This paper describes an automated cell segmentation method for localizing the cells of Chinese hamster ovary cell culture. Several kinds of high-dimensional feature descriptors, K-means clustering method and Chan-Vese model-based level set are used to extract the cellular regions. The region extracted are used to classify phases in cell cycle. The segmentation results were experimentally assessed. As a result, the proposed method proved to be significant for cell isolation. In the evaluation experiments, we constructed a database of Chinese Hamster Ovary Cell’s microscopic images which includes various photographing environments under the guidance of a biologist.

Transient Wave Propagation in a General Dispersive Media Using the Laguerre Functions in a Marching-on-in-Degree (MOD) Methodology
Baek-Ho Jung;Zicong Mei;Tapan Kumar Sarkar
PIER , 2011, DOI: 10.2528/PIER11052408
Abstract: The objective of this paper is to illustrate how the marching-on-in-degree (MOD) method can be used for efficient and accurate solution of transient problems in a general dispersive media using the finite difference time-domain (FDTD) technique. Traditional FDTD methods when solving transient problems in a general dispersive media have disadvantages because they need to approximate the time domain derivatives by finite differences and the time domain convolutions by using finite summations. Here we provide an alternate procedure for transient wave propagation in a general dispersive medium where the two issues related to finite difference approximation in time and the time consuming convolution operations are handled analytically using the properties of the associate Laguerre functions. The basic idea here is that we fit the transient nature of the fields, the permittivity and permeability with a series of orthogonal associate Laguerre basis functions in the time domain. In this way, the time variable can not only be decoupled analytically from the temporal variations but that the final computational form of the equations is transformed from FDTD to a FD formulation in the differential equations after a Galerkin testing. Numerical results are presented for transient wave propagation in general dispersive materials which use for example, a Debye, Drude, or Lorentz models.
Arabidopsis COMPASS-Like Complexes Mediate Histone H3 Lysine-4 Trimethylation to Control Floral Transition and Plant Development
Danhua Jiang,Nicholas C. Kong,Xiaofeng Gu,Zicong Li,Yuehui He
PLOS Genetics , 2011, DOI: 10.1371/journal.pgen.1001330
Abstract: Histone H3 lysine-4 (H3K4) methylation is associated with transcribed genes in eukaryotes. In Drosophila and mammals, both di- and tri-methylation of H3K4 are associated with gene activation. In contrast to animals, in Arabidopsis H3K4 trimethylation, but not mono- or di-methylation of H3K4, has been implicated in transcriptional activation. H3K4 methylation is catalyzed by the H3K4 methyltransferase complexes known as COMPASS or COMPASS-like in yeast and mammals. Here, we report that Arabidopsis homologs of the COMPASS and COMPASS-like complex core components known as Ash2, RbBP5, and WDR5 in humans form a nuclear subcomplex during vegetative and reproductive development, which can associate with multiple putative H3K4 methyltransferases. Loss of function of ARABIDOPSIS Ash2 RELATIVE (ASH2R) causes a great decrease in genome-wide H3K4 trimethylation, but not in di- or mono-methylation. Knockdown of ASH2R or the RbBP5 homolog suppresses the expression of a crucial Arabidopsis floral repressor, FLOWERING LOCUS C (FLC), and FLC homologs resulting in accelerated floral transition. ASH2R binds to the chromatin of FLC and FLC homologs in vivo and is required for H3K4 trimethylation, but not for H3K4 dimethylation in these loci; overexpression of ASH2R causes elevated H3K4 trimethylation, but not H3K4 dimethylation, in its target genes FLC and FLC homologs, resulting in activation of these gene expression and consequent late flowering. These results strongly suggest that H3K4 trimethylation in FLC and its homologs can activate their expression, providing concrete evidence that H3K4 trimethylation accumulation can activate eukaryotic gene expression. Furthermore, our findings suggest that there are multiple COMPASS-like complexes in Arabidopsis and that these complexes deposit trimethyl but not di- or mono-methyl H3K4 in target genes to promote their expression, providing a molecular explanation for the observed coupling of H3K4 trimethylation (but not H3K4 dimethylation) with active gene expression in Arabidopsis.
面向网络延迟均衡性的片上网络交叉开关分配策略
王子聪, 陈小文, 郭阳
WANG Zicong
, CHEN Xiaowen, GUO Yang

- , 2018,
Abstract: 针对路由器中的交叉开关分配,提出面向网络延迟均衡性的分配策略,旨在通过更加公平的交叉开关分配策略提升网络延迟均衡性,从而进一步提升系统性能。通过在全系统模拟器上运行SPEC CPU2006实验表明,与传统的分离式分配策略和最新的TS-Router分配策略相比,延迟标准差分别平均降低了13.8%和3.9%,而最大延迟分别平均降低了45.6%和15.1%。在系统性能方面,相比于TS-Router,所提分配策略在IPC上平均提升了0.8%。在分离式分配器的基础上完成了硬件实现,并给出了速度、面积和功耗方面的开销评估。
According to the problem of switch allocation, a network latency equalization-oriented switch allocation strategy was proposed to improve system performance by designing a more fairness switch allocation strategy and improving the degree of network latency equalization. The evaluation of the design with SPEC CPU2006 benchmarks was performed in a full-system simulator. Compared with the canonical separable switch allocator and the TS-Router (recently proposed switch allocator), the experiments show that the approach decreases LSD (latency standard deviation) by 13.8% and 3.9% respectively, as well as ML (maximum latency) by 45.6% and 15.1% respectively. The approach improves system throughput by 0.8% over that of TS-Router. Finally, the design is implemented based on the separable switch allocator, and it can perform the evaluation in speed, area and power.
Experimental Research on Monomial Cooling Measure of Greenhouse in Summer  [PDF]
Jian Hu
Smart Grid and Renewable Energy (SGRE) , 2013, DOI: 10.4236/sgre.2013.41007
Abstract:

This paper describes several main monomial cooling methods of greenhouse in summer, including natural ventilation, mechanical ventilation, wet curtain cooling, external sun-shading etc., as well as analyzes the change law of the environment on temperature and humidity in greenhouse. The result shows that the four cooling methods stated above make the temperature gradients between internal and external respectively 1.1, 0.4, -2.6℃ and -1.2,so it is obvious that the cooling effect of wet curtain cooling is the optimum; and the internal and external humidity difference is respectively: -13%, 6%, 8% and 1%.

Age Distribution of a Zero-Growth Population: Implications for China  [PDF]
Song Jian
Chinese Studies (ChnStd) , 2013, DOI: 10.4236/chnstd.2013.22011
Abstract: It is generally accepted that zero-growth population would be the long-term destiny of any population. China’s population is expected to reach 1.4 billion with zero-growth around 2030, if the low fertility policy continues up to then. Demographic dynamics indicate that the age composition of a steady zero-growth society would asymptotically approach the population mix of today’s many developed countries. Here we present a brief analysis and some insights into the age composition of a zero-growth society and the connectedness between total fertility rate, net reproduction rate and replacement level of fertility. Other formulas useful for demographic studies are also provided to further the analysis. Our results reveal that the age composition of China’s population in 2050 would be similar to those of some developed countries today. We argue that the misgivings about “population aging” or the fear of a “winter of humanity” in China stem from rather oversimplified estimations.
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