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Search Results: 1 - 10 of 121702 matches for " Ying-zi Zhang "
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Influence of Simulated Acid Rain Corrosion on the Uniaxial Tensile Mechanical Properties of Concrete
Ying-zi Zhang,Ying-fang Fan,Hong-nan Li
International Journal of Corrosion , 2012, DOI: 10.1155/2012/172394
Abstract: An experimental study on the uniaxial tensile property of concrete exposed to the acid rain environment was carried out. Acid rain with pH level of 1.0 was deposed by the mixture of sulfate and nitric acid solution in the laboratory. Dumbbell-shaped concrete specimens were immersed in the simulated acid rain completely. After being exposed to the deposed mixture for a certain period, uniaxial tensile test was performed on the concrete specimens. The results indicate that elastic modulus, tensile strength, and peak strain have a slight increase at the initial corrosion stage, and with the extension of corrosion process, elastic modulus and tensile strength decrease gradually, while the peak strain still increases. It is found that the compressive strength is more sensitive than the tensile strength in aggressive environment. Based on the experimental results, an equation was proposed to describe the ascending branch of the stress-strain curve of the concrete corroded by acid rain. 1. Introduction Acid rain has become an issue of widespread concern in Asia, and it was first recognized as a potential environmental pollution problem in the late 1970s and early 1980s. It was also an increasing problem in China during the last decades [1–4]; one third of China’s land mass was affected by acid rain. The acid rain is composed of acid substances, such as H2SO4, HCl, and HNO3, which readily react with Ca(OH)2 and form CaSO4·2H2O, Ca(NO3)2·4H2O, and CaCl2·6H2O. Because the solubility of these products is higher than that of CaCO3, which is formed at the surface by the reaction of Ca(OH)2 with CO2 (carbonation), they are dissolved in rainwater and penetrate into the inner pores of concrete. After the evaporation of rainwater, these salts redeposit and give rise to stress in the concrete structure, resulting in cracking, mass loss, and eventually structural failure. In the early 1950s, US Environmental Protection Agency reported that the cost of repairing or replacing the concrete structure every year due to acid rain in the United States was more than $5 billion dollars. In Britain, the economic loss due to acid rain was 0.15% of the GNP. Guo [5] in 2001 estimated that the direct material loss due to acid rain only in Guangzhou was 1.2 billion Chinese Yuan. Although some ways have been used to reduce acid rain, the acid rain region in China even continue to expand, therefore, the property of the corroded concrete have become to be a critical issue and attracted a lot of researchers worldwide [6–12]. However, due to the complicated mechanism, there remains only very
Forecast of Power Generation for Grid-Connected Photo-voltaic System Based on Grey Theory and Verification Model  [PDF]
Ying-zi Li, Jin-cang Niu, Li Li
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B034
Abstract: Being photovoltaic power generation affected by radiation strength, wind speed, clouds cover and environment temperature, the generating in each moment is fluctuating. The operational characteristics of grid-connected PV systems are coincided with gray theory application conditions. A gray theory model has been applied in short-term forecast of grid-connected photovoltaic system. The verification model of the probability of small error will help to check the accuracy of the gray forecast results. The calculated result shows that the  model accuracy has been greatly enhanced.
The effect of thickness on the structure and superconductivity of La1.85Sr0.15CuO4 films

Zu Min,Zhang Ying-Zi,Wen Hai-Hu,

物理学报 , 2008,
Abstract: Highly c-oriented La1.85Sr0.15CuO4 (LSCO) films were successfully deposited on SrTiO3 (STO) substrates by on-axis magnetron sputtering. By using the standard four-probe technique and X-ray diffraction (XRD), we investigated the influence of film thickness on the structure and superconductivity of LSCO(x=0.15) films. The experiment results show that the full-width at half maximum (FWHM) of the (006) rocking curve decreases with increasing film thickness, which indicates that the crystal qualities of films are improved. Meanwhile, the superconducting transition temperature is higher for the thicker films.
Cloning, sequence analysis and expression of N-acetylglutamate kinase gene in Corynebacterium crenatum

HAO Ning,ZHAO Zhi,WANG Yu,ZHANG Ying-zi,DING Jiu-yuan,CAO Qin,

微生物学报 , 2006,
Abstract: N-Acetylgutamate kinase(EC;NAGK) genes from wild-type Corynebacterium crenatum AS 1.542 and a L-arginine-producing mutant C.crenatum 971.1 were cloned and sequenced.Analysis of argB sequences revealed that only one ORF existed,which used ATG as the initiation codon and coded a peptide of 317 amino acids with a calculated molecular weight of 33.6kDa.Only one nucleotide difference was found in the structure gene and the difference did not cause a change of amino acid by comparision of the gene sequences between the wild type C.crenatum AS 1.542 and the mutant 971.1.The ORF sequence of argB from C.crenatum AS 1.542 showed homologies of 99.89%,76.62%,37.94% to those from Corynebacterium glutamicum ATCC 13032,Corynebacterium efficiens YS-314 and Escherichia coli k12.And the amino acid sequence deduced from ORF displayed homologies of 100%,78.55%,25.25% to those from microorganisms above,respectively.An internal promoter was found in the upstream of the argB gene from C.crenatum.The argB gene from C.crenatum AS 1.542 was expressed both in C.crenatum AS 1.542 and 971.1.The NAGK activity of transformed C.crenatum AS 1.542 was greatly increased by the induction of IPTG.The NAGK activity of transformed C.crenatum 971.1 was almost twice as much as that of C.crenatum 971.1 under the same induction.The amplification of the NAGK activity yielded 25% increase of L-arginine production in C.crenatum 971.1.
Cloning, sequence analysis and expression of alanine racemase gene in Pseudomonas putida

CAO Qin,ZHAO Zhi,ZHANG Ying-zi,WANG Yu,DING Jiu-yuan,

微生物学报 , 2006,
Abstract: 从恶臭假单胞菌(Pseudomonas putida)200的基因组出发,用PCR方法克隆到两个独立作用的丙氨酸消旋酶基因,称之为dadX和alr。DadX编码357个氨基酸长的多肽,计算分子量为38.82kDa,alr编码409个氨基酸长的多肽,计算分子量为44.182kDa。序列分析显示,DadX的氨基酸序列与Pseudomonas putidaKT2440,铜绿假单胞菌(Pseudomonas aeruginosa),鼠伤寒沙门氏菌(Salmonella typhimurium)和大肠杆菌(Escherichia coli)的DadX比较,相似性分别为96.64%、71.99%、44.88%和47.37%。Alr的氨基酸序列与Pseudomonas putidaKT2440比较,同源性为94.38%,而与铜绿假单胞菌(P.aeruginosa)、鼠伤寒沙门氏菌(S.typhimurium)和大肠杆菌(E.coli)的Alr比较,同源性均较低,分别为22.89%、25.72%和26.44%。在P.putida200的DadX和Alr氨基酸序列中部发现有对于酶活性至关重要的保守区域,如磷酸吡哆醛(PLP)结合位点。DadX和alr在大肠杆菌中得到表达,DadX丙氨酸消旋酶只对丙氨酸有消旋作用,而Alr丙氨酸消旋酶可以作用于丙氨酸和丝氨酸两种底物,且对丝氨酸特异性更高。Alr的表达不依赖于外源启动子,说明在其结构基因上游存在启动子结构。
Construction of Corynebacterium glutamicum/E.coli shuttle promoter-probe vector

LI Kai,ZHAO Zhi,ZHANG Ying-zi,WANG Yu,DING Jiu-yuan,

微生物学报 , 2007,
Abstract: Based on the replication origins of the C. glutamicum pXZ10145 and the Escherichia coli ColE1 plasmid, a novel Corynebacterium glutamicum/Escherichia coli shuttle vector pAK6 was constructed. This vector was able to replicate in C. glutamicum and E. coli. Plasmid pAK6 carried multiple cloning site useful for gene cloning, kanamysin- and ampicillin-resistance-encoding gene. Furtherly based on the shuttle vector pAK6, a promoter-probe vector was developed for the isolation of promoter elements from C. glutamicum . This vector carried the promoterless chloramphenicol acetyltranstersae (CAT) gene as a reporter downstream from useful cloning site. For testing this promoter-probe vector, C. glutamicum genomic DNA was digested to completion with Sau3AI and the fragments shot-gun cloned into its unique Bgl II. Two fragments exhibiting promoter activity were isolated. By measuring CAT activity, the strength of promoter fragments was assayed. After being sequenced, promoter sequences were predicted by using BDGP Neural Network Promoter Prediction V2.2 and the similarities to the regions of the consensus promoter sequence or the known promoters were confirmed.
Cloning, sequence analysis and expression of anthranilate synthetase gene in Corynebacterium pekinense

CHEN Xiao-fang,ZHAO Zhi,ZHANG Ying-zi,WANG Yu,DING Jiu-yuan,

微生物学报 , 2007,
Abstract: Anthranilate synthetase (EC4.1.3.27;AS) genes from wild-type Corynebacterium pekinense AS1.299 and its mutant PD-67 were cloned and sequenced. Analysis of PCR fragments revealed that three ORFs existed, which corresponded to trpL, trpE and trpG gene, respectively. Six bases changes that resulted in the changes of five amino acids were found in the trpE structural gene of C. pekinense PD-67 and a single-base change that resulted in an amino acid substitution was found in the trpG structural gene of C. pekinense PD-67.A homology comparison revealed that C. pekinense AS1.299 was closely related to Corynebacterim glutamicum ATCC 13032 and Brevibacterium lactofermentum. An internal promoter was found in the upstream of the trpL gene from C. pekinense and it functioned in E. coli, but a single-base exchange (A to G) existed in the-35 box of PD-67.The trpEG genes from the wild-type strain and its mutant were expressed both in C. pekinense AS1.299 and PD-67, and the specific enzyme activities of transformed C. pekinense were much higher than that of the parental strains. The amplification of the activity of AS yielded 22.39% increase of L-tryptophan production, but the cell growth became slower than PD-67.
A Model of the Abrasive Wear of Composites Reinforced by Three-dimensional Network Structure

WANG Shou-ren,GENG Hao-ran,ZHANG Jing-chun,WANG Ying-zi,

摩擦学学报 , 2006,
Abstract: 考虑网络结构增强体特殊的拓扑结构因素和弹性模量影响,利用复合材料磨损率最小化和最大化假设,建立了网络结构增强复合材料的磨损模型,同时制备了不同体积分数的Si3N4陶瓷增强Al-Mg合金复合材料,并将其磨损试验结果数据拟合到模型中.结果表明,所建立的模型可以反映复合材料增强相的体积分数、复合材料的弹性模量和磨损率之间的数学关系,证明复合材料的摩擦磨损率随增强相体积分数的增加而逐渐降低,当体积分数超过45%~50%时,磨损率随增强相体积分数的增加而逐渐增大.该模型不同于Khruschov模型和Zum-Gahr 模型,其关系不遵循线性规则.与增强体复合材料的磨损试验数据拟合表明,该模型能够较好地反映网络结构增强复合材料的磨损性能,具有一定普遍性.
Application and research of Web hits from using AR model

ZHAO Ying-zi,

重庆邮电大学学报(自然科学版) , 2006,
Abstract: 对数据挖掘的“预测”功能进行了研究,在对网站进行流量统计的基础上,利用AR模型建立点击量时间序 列模型进行点击量的预测,同时也与其他常用的预测方法进行对比。从实验结果可以看出AR模型的预测精度要 优于其他的预测方法,达到了预期的精度要求。
Fractal features of scenic spatial construction in Wuyishan World Natural and Culture Heritage

ZHANG Chun-Ying,HONG Wei,WU Cheng-Zhen,HONG Tao,CHEN Can,LI Jian,WANG Ying-Zi,
,洪 伟,吴承祯,洪 滔,陈 灿,李 键,王英姿

中国生态农业学报 , 2009,
Abstract: By using box dimension, information dimension and correlation dimension, fractal features of Wuyishan Natural and Culture Heritage were studied at a multi-dynamic scale. At the A sampling scale (with 1.474 box dimension, 1.415 information dimension, and 1.048 correlation dimension ), the derived correlation coefficients (R) are 0.994, 0.999 and 0.969. At the B sampling scale, box dimension ranges from B1 to B4, the correlation coefficient ranges from 0.825 ~ 1.200, R values are all above 0.961. The range of information dimension is 0.919 ~ 1.302 with R values above 0.964. Correlation dimension range is 0.822 ~ 1.364 with R values above 0.941. At the C sampling scale, range of box dimension is C1 ~ C16 (excluding plots with spot quantity between 0 ~ 1), the correlation coefficient is 0.175 ~ 0.931 with R values above 0.775. That of information dimension is 0.200 ~ 1.039 with R values above 0.771. Correlation dimension range is 0.506 ~ 1.929 with R values above 0.704. It is thus concluded that: the scenery system of Wuyishan Natural and Culture Heritage has obvious fractal characteristics. Furthermore, the fractal dimensions are sensitive to sampling scale.
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