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Search Results: 1 - 10 of 80920 matches for " Zhenzhong Liu "
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Performance Evaluation of a New Type of Polymer Profile Control Agent  [PDF]
Qingwang Liu, Zhe Zhang, Zhenzhong Fan, Zhenzhong Fan, Jigang Wang
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.65040
Abstract: The low-permeability oil and gas resources of our country are quite common and abundant. Their reserve has accounted for one-fifth of total oil reserves of our country, and their yield has constituted the important part of national petroleum annual yield, but its development is very difficult. Polymer gel technology is a technical method of improving sweep efficiency in recent years which substantially increases the viscosity of the polymer solution by adding a crosslinking agent to the polymer produced by intramolecular or intermolecular crosslinking.
The Synthesize and Property Evaluation of High Temperature Resistant Phenolic Resin-Type Profile Control Agent  [PDF]
Qingwang Liu, Hongwei Mu, Jigang Wang, Zhenzhong Fan
Open Journal of Composite Materials (OJCM) , 2014, DOI: 10.4236/ojcm.2014.43019
Abstract:

Most of the mining method of domestic oilfield is waterflood development, thus the water content in the mid and late water flooding would rise faster, and the oil recovery rate would decline relatively more rapid. So it is very important to research profile control agent for stabilizing oil production resin-type profile control agent, and focus on researching the themal stability, shear resistance, gelation time and gelation strength and other properties of this profile control agent [1]. Finally, the best ratio for synthesizing the high temperature resistant phenolic resin-type profile control agent was obtained.

An Automatic Text Region Positioning Method for the Low-Contrast Image  [PDF]
Gongqin Liu, Murong Jiang, Helin Cun, Zhenzhong Shi, Jianyu Hao
Journal of Computer and Communications (JCC) , 2017, DOI: 10.4236/jcc.2017.510005
Abstract: Text extraction is the key step in the character recognition; its accuracy highly relies on the location of the text region. In this paper, we propose a new method which can find the text location automatically to solve some regional problems such as incomplete, false position or orientation deviation occurred in the low-contrast image text extraction. Firstly, we make some pre-processing for the original image, including color space transform, contrast-limited adaptive histogram equalization, Sobel edge detector, morphological method and eight neighborhood processing method (ENPM) etc., to provide some results to compare the different methods. Secondly, we use the connected component analysis (CCA) method to get several connected parts and non-connected parts, then use the morphology method and CCA again for the non-connected part to erode some noises, obtain another connected and non-connected parts. Thirdly, we compute the edge feature for all connected areas, combine Support Vector Machine (SVM) to classify the real text region, obtain the text location coordinates. Finally, we use the text region coordinate to extract the block including the text, then binarize, cluster and recognize all text information. At last, we calculate the precision rate and recall rate to evaluate the method for more than 200 images. The experiments show that the method we proposed is robust for low-contrast text images with the variations in font size and font color, different language, gloomy environment, etc.
The Synergistic Effects Study of C-myc and C-erbB-2 in the Carcinogenesis of Gastric Carcinoma  [PDF]
Keqiang Wang, Jiangang Liu, Yanchao Duan, Shengyi Dongye, Jiafeng Wu, Yiren Wang, Zhenzhong Liu, Guoxin Han
Open Journal of Gastroenterology (OJGas) , 2017, DOI: 10.4236/ojgas.2017.712032
Abstract: Objective: To study the significance of c-myc and c-erbB-2 oncogene expression in gastric cancer. Methods: 81 gastric cancer specimens were detected for c-myc and c-erbB-2 oncogene amplification using non-radioactive in situ hybridization method. Results: The amplification rates for c-myc and c-erbB-2 were 67.9% and 50.6% respectively, and there were significant correlation in the amplification of these two genes (χ2 = 7.26, P < 0.01). Conclusions: The amplification of c-myc and c-erbB-2 may play an important role in gastric cancer development, and these two genes may have synergistic effect.
Synthesis and Performance Evaluation of Organic Bentonite Modifier Dimethyldistearylammonium Bromide (DODMAB)  [PDF]
Qingwang Liu, Ao Sun, Zhenzhong Fan, Jiguang Wang, Tong Zhang, Dong Cheng
Open Journal of Composite Materials (OJCM) , 2014, DOI: 10.4236/ojcm.2014.44024
Abstract: Dimethyldistearylammonium Bromide (DODMAB) is a bentonite modifier with good performance. In this experiment, 1-Bromooctadecane is the raw material, and completes tertiary amination and quaternization successively by changing the condition of experiment. The result is that the productivity can achieve 78.94% in the synthesis of DODMAB. It has been used in the experiment of bentonite modification and achieves good results; compared with using trimethylstearylammonium bromide as the organic modifier, the synthetic organic bentonite has better performance than the common organic modifier when used in the oil base drilling fluid of oilfield operation.
The Synthesis and Evaluation of a Novel Inhibitor DN for Carbon Dioxide Corrosion  [PDF]
Qingwang Liu, Tong Zhang, Jigang Wang, Zhenzhong Fan, Ao Sun, Dong Cheng
Open Journal of Composite Materials (OJCM) , 2014, DOI: 10.4236/ojcm.2014.44023
Abstract: During the oil and gas wells exploitation and transportation, carbon dioxide corrosion is one of main reasons for the corrosion of metallic materials. So the methods of preventing and reducing carbon dioxide corrosion have become a widely focused problem. The foreign and domestic practices and experiences show that as an economic, effective and versatile metal corrosion control method, corrosion inhibitor protection technology is suitable for application in oil and gas transportation system. This paper, through the indoor experiment with benzyl chloride, using quinoline as raw materials, synthesizes a kind of quinoline quaternary ammonium salt. The obtained product benzyl chloride quinoline compounded with OP-10 and ethanol to get a novel inhibitor DN for carbon dioxide corrosion, and to evaluate its performance.
The Synthesis and Evaluation of Hydrophobic Association Thickener  [PDF]
Qingwang Liu, Dong Cheng, Jigang Wang, Zhenzhong Fan, Tong Zhang, Ao Sun
Open Journal of Composite Materials (OJCM) , 2015, DOI: 10.4236/ojcm.2015.51001
Abstract: The paper provides a new hydrophobic association polymer fracturing fluid gelatinizer. The hydrophobic association which is the synthesis of three component copolymer complexes, is compounded by micellar copolymerization method. The hydrophobic association is got together through hydrophilic monomer acrylamide monomer N,N-vinyl pyrrolidone monomer with a rigid group N, and hydrophobic monomer N,N-2 dodecyl acrylamide etc. three monomers with sodium dodecyl sulfate as the emulsifier in micellar solution.
High expression of EPO gene using un-dhfr negative cell
Zhenzhong Cui,Pengpeng Liu,Shunzhang Qi,Heng Shen
Chinese Science Bulletin , 1998, DOI: 10.1007/BF03186992
Abstract: Erythropoietin (EPO) genomic gene was cloned and its expression vector pOP13/EPO was constructed. CHO-K12 cell was transfected by this vector using lipofectin method. A stable expression cell strain C10 cell with the EPO production at 160IU/d in 106 cells were obtained at 400 μg/mL G418. Based on the C10 cell, another vector pHY/dhfr (dihydrofolate reductase) that carries a dhfr gene and a selecting marker of hygromycin B resistant gene was transferred to this cell. Several cell clones were obtained at 200 μg/mL hygromycin B. These cell clones that can express both EPO gene and exogenous dhfr gene were selected under the progressively increased concentration to 1 μmol methotrexate (MTX). Some high EPO expression cell clones were obtained, the highest expression was 2 400 IU/d in 106 cells, 15 times higher than that without MTX pressure. Then, a method of EPO high expression by using un-dhfr negative cell was primarily established. EPO bioactivity was found by using TF-1 cell.
Dissolution and grain growth of nano-Ag-Cu alloy
Zhenzhong Qi,Hui Shen,A. Günther,Xianghuai Liu
Chinese Science Bulletin , 1997, DOI: 10.1007/BF03182795
Abstract: The nc-Ag-Cu alloy has been prepared by means of IGC and compressed to a disk with Φ30 mm × 0. 2 mmin situ. The grain size of as-compressed nc alloy is in the range of 4–5 nm. During annealing process, supersaturated α-Ag and α-Cu dissolved with activation energies ΔHAg = 0.053 eV and ΔHCu =0.029 eV. After dissolution of Ag and Cu, the lattice parameters of α-Ag and α-Cu return to that of matrix alloy. At the third stage, nanocrystallite of α-Ag and α-Cu grows with the same growth activation energies ΔHG= 0.295 eV.
Synthesis of 3-D ordered macroporous silicate using the template formed from monodispersed polystyrene latex
Kai Qi,Zhenzhong Yang,Lijun Wang,Zhengping Liu,Delu Zhao
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02884977
Abstract: Based on the template formed from monodispersed polystyrene (PS) latex, a modified fast sol-gel process was employed to synthesize a three-dimensional (3-D) ordered macroporous silica material after removing the template by calcination at high temperature. It was indicated that there existed highly ordered packed pores within the whole silica material by SEM morphology observation. It was also found that the pores were interconnected. The pore size could be controlled mainly by varying the particle size of the latex ranging from 101 to 102 nm. The formation process of the ordered pores was also preliminarily discussed.
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