Research on profile inversion pattern of polymer flooding

Ailing Zheng,Qianghan Feng,Qiansheng Wei,Dehua Liu 한국자원공학회 2018 Geosystem engineering Vol.21 No.3

Polymer flooding is becoming more common and more successful, and has made a great contribution to EOR. However, the statistical analysis of water injection profile data shows that the injection profile easily inverses during the process of single slug polymer flooding in heterogeneous reservoir. It is unfavorable for enhancing oil recovery. According to seepage mechanics theory, the cognition is determined that the injection rate distribution in high and low permeability layers depends on reservoir heterogeneity and physicochemical property of polymer. The basic reason of profile inversion lies in the different dynamic variation of resistance factors in the high and low permeability layers. In order to use existing reservoir simulation software to accurately describe the profile inversion characteristics, a processing method is submitted which is that different polymer characteristic parameters and relative permeability curves are assigned to different regions according to the distributions of reservoir characteristics during polymer flooding. Then, this processing method is used for systematically studying the profile inversion laws of different permeability ratio, polymer concentration and injecting-polymer occasion. The results show that these factors have great influence on the profile inversion. This provides a technical support for studying the profile inversion rules and corresponding improvement method.

Investigation on dynamic responses of dual-axis positioning mechanism for satellite antenna considering joint clearance

Zheng Feng Bai,Yu Qiang Liu,Yi Sun 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.2

The effects of clearance on dynamic responses of dual-axis positioning mechanism of a satellite antenna are investigated using a computationalmethodology. Considering clearances in joints, the clearance is defined and the mathematical model of revolute joint withclearance is presented. The normal contact force model and tangential friction model in clearance joint are established using nonlinearcontinuous contact force model and Coulomb friction model, respectively. Then numerical simulation is used to investigate the dynamicresponses of dual-axis positioning mechanism with joint clearance. The results show that clearance has significant effects on dynamicresponses of mechanism, and the investigation of the work can predict the dynamic responses of dual-axis positioning mechanism withclearance preferably, which is the basis of mechanism design, precision analysis and control system design.

A triage strategy in advanced ovarian cancer management based on multiple predictive models for R0 resection: a prospective cohort study

Zheng Feng,Hao Wen,Zhaoxia Jiang,Shuai Liu,Xingzhu Ju,Xiaojun Chen,Lingfang Xia,Junyan Xu,Rui Bi,Xiaohua Wu 대한부인종양학회 2018 Journal of Gynecologic Oncology Vol.29 No.5

Objective: To present the surgical outcomes of advanced epithelial ovarian cancer (AEOC) since the implementation of a personalized approach and to validate multiple predictive models for R0 resection. Methods: Personalized strategies included: 1) Non-invasive model: preoperative clinico-radiological assessment according to Suidan criteria with a predictive score for all individuals. Patients with a score 0–2 were recommended for primary debulking surgery (PDS, group A), or otherwise were counseled on the choices of PDS, neoadjuvant chemotherapy (NAC, group B) or staging laparoscopy (S-LPS). 2) Minimally invasive model: S-LPS with a predictive index value (PIV) according to Fagotti. Individuals with a PIV <8 underwent PDS (group C) or otherwise received NAC (group D). Intraoperative assessment (with Eisenkop, peritoneal cancer index [PCI], and Aletti scores) and surgical results were prospectively collected. Results: Between September 2015 and August 2017, 161 pathologically confirmed epithelial ovarian cancer patients were included. A total of 52 (32.3%) patients had a predictive score of 0–2, and 109 (67.7%) patients had a score ≥3. Among these individuals, 41 (25.5%) patients received S-LPS. Finally, 110 (68.3%) patients underwent PDS (A+C), and 51 (31.7%) patients received NAC (B+D). The R0 resection rates in PDS and NAC patients were 56.4% and 60.8%, respectively. The area under the curve (AUC) of Suidan criteria was 0.548 for group (A+C). The AUC of Fagotti score was 0.702 for group C. The AUC of Eisenkop, PCI, and Aletti scores were 0.808, 0.797, and 0.524, respectively. Conclusion: The Suidan criteria were not effective in these AEOC patients. S-LPS was helpful in decision-making for PDS and should be endorsed in the future.

HDDM, a formula consisting of seven herbs, had anti-diabetic but no immunomodulatory activities in multiple low doses of streptozotocin-treated female of B6C3F1 mice

Zheng, Jian Feng,Guo, Tai L Kyung Hee Oriental Medicine Research Center 2009 Oriental pharmacy and experimental medicine Vol.9 No.1

The objectives of this study were to determine the effect of herb formula HDDM, a modification of Huangdan decoction that has been shown to be effective in the treatment of glomerulonephritis and chronic renal failure, on the blood glucose levels in multiple low doses (MLD; 50 mg/kg for five consecutive days) of streptozotocin (STZ)-treated female B6C3F1 mice. Initial studies were performed to compare diabetes induction in five strains (e.g., B6C3F1, NOD, CD-1, C3H/HeN and C57BL/6) of mice by MLD-STZ, and immune changes following the treatment. The results suggested that the order of susceptibility to diabetes induction was NOD $\approx$ CD-1 > B6C3F1 $\approx$ C3H > C57BL/6. Furthermore, STZ modulation of T cell development, differentiation and activation might play a role in diabetes induction by MLD-STZ treatment. MLD-STZ-induced diabetes in female B6C3F1 mice was moderate, which allowed the evaluation of drug-induced protection or exacerbation of diabetes to be performed. As such, modulation of blood glucose by HDDM, which consisted of Da Huang (Radix Et Rhizoma Rhei), Huang Qi (Radix Astragali Seu Hedysari), Dan Shen (Radix Salviae Miltiorrhizae), Yin Yang Huo (Herba Epimedii), Yi Yi Ren (Semen Coicis or Coix lacryma-jobi), Mai Dong (Radix Ophiopogonis) and Shan Zhu Yu (Fructus Corni), was evaluated in MLD-STZ-treated female B6C3F1 mice. The results suggested that HDDM could lower the blood glucose levels, but it had no immunomodulatory activities. Additionally, HDDM-treated mice exhibited improved glucose tolerance. In conclusion, these studies have suggested that MLD-STZ-induced diabetes in female B6C3F1 mice is a useful model to evaluate drug modulation of diabetes, and that the herb formula HDDM possesses anti-diabetic effects.

Optimization of Parameters for LCL Filter of Least Square Method Based Three-phase PWM Converter

Zheng, Hong,Liang, Zheng-feng,Li, Meng-shu,Li, Kai The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

LCL filters are widely used in three-phase PWM converter for its advantages of small volume, low cost and inhibition of high frequency current harmonic. However, it is difficult to optimize its design because its parameters are mutually influenced while the value of each parameter for LCL filter has impacts on the converter's cost and size. In this paper, the target of optimization is to minimize the parameter values of LCL filter, and an optimization method for parameters of LCL filter of three-phase PWM converter based on least square method is proposed. With this method, a quantitative calculation of the harmonic component of the converter’s side phase voltage is performed first, and then the quantitative relationship between phase voltage harmonics and grid phase current harmonics is analyzed. After that, the attenuation requirement of each harmonic is obtained by taking into account the requirements for each harmonic component of grid current. Then according to the optimization objective, the objective function with minimum harmonic attenuation deviation is established, and least squares method is adopted for three-dimensional global searching of parameters for LCL filter. Thus, the designed harmonic attenuation curve approximates the minimum attenuation requirements, and the optimized LCL filter parameters are obtained. Finally, the effectiveness of the method is verified by the experiments.

Research Articles : The Influence of Challenge on Cathepsin B and D Expression Patterns in the Silkworm Bombyx mori L

( Feng Yao Wu ),( Feng Ming Zou ),( Jun Qiang Jia ),( Sheng Peng Wang ),( Guo Zheng Zhang ),( Xi Jie Guo ),( Zhong Zheng Gui ) 한국잠사학회 2011 International Journal of Industrial Entomology Vol.23 No.1

Cathepsins are well-characterized proteases that are ubiquitously expressed in lysosomes. Previous work revealed that Bombyx mori cathepsins B and D are expressed in the fat body and undergo decomposition during larval-pupal metamorphosis. Quantitative RTPCR was performed to detect cathepsin gene expression at the transcription level when challenged by B. mori nuclear polyhedrosis virus (BmNPV), temperature and hormones (20-hydroxyecdysone (20E) and juvenile hormone analogue (JHA)). mRNAs encoding cathepsins B and D were significantly enhanced after the larvae were infected with BmNPV, and the peak of the induction appeared at 1 day before spinning. This attenuated the inducing effect on cathepsin expression caused by infection. Temperature shock induced cathepsin expression at the later stage of the 5th instar, and transcription levels varied with development stage and temperature. Cathepsin B and D mRNA expression in the fat body were significantly induced by JHA at the day before spinning, and with 20E, the expression reached a peak at the last day of the 5th instar. Cathepsin B and D mRNA expression exhibited detectable changes post-treatment, without significant differences between or among the hormone concentrations.

Defining the N-Linked Glycosylation Site of Hantaan Virus Envelope Glycoproteins Essential for Cell Fusion

Feng Zheng,Lixian Ma,Lihua Shao,Gang Wang,Fengzhe Chen,Ying Zhang,Song Yang 한국미생물학회 2007 The journal of microbiology Vol.45 No.1

The Hantaan virus (HTNV) is an enveloped virus that is capable of inducing low pH-dependent cell fusion. We molecularly cloned the viral glycoprotein (GP) and nucleocapsid (NP) cDNA of HTNV and expressed them in Vero E6 cells under the control of a CMV promoter. The viral gene expression was assessed using an indirect immunofluorescence assay and immunoprecipitation. The transfected Vero E6 cells expressing GPs, but not those expressing NP, fused and formed a syncytium following exposure to a low pH. Monoclonal antibodies (MAbs) against envelope GPs inhibited cell fusion, whereas MAbs against NP did not. We also investigated the N-linked glycosylation of HTNV GPs and its role in cell fusion. The envelope GPs of HTNV are modified by N-linked glycosylation at five sites: four sites on G1 (N134, N235, N347, and N399) and one site on G2 (N928). Site-directed mutagenesis was used to construct eight GP gene mutants, including five single N-glycosylation site mutants and three double-site mutants, which were then expressed in Vero E6 cells. The oligosaccharide chain on residue N928 of G2 was found to be crucial for cell fusion after exposure to a low pH. These results suggest that G2 is likely to be the fusion protein of HTNV.

Coefficient charts for active earth pressures under combined loadings

Zheng, De-Feng,Nian, Ting-Kai,Liu, Bo,Yin, Ping,Song, Lei Techno-Press 2015 Geomechanics & engineering Vol.8 No.3

Rankine's theory of earth pressure cannot be directly employed to c-${\phi}$ soils backfill with a sloping ground subjected to complex loadings. In this paper, an analytical solution for active earth pressures on retaining structures of cohesive backfill with an inclined surface subjected to surcharge, pore water pressure and seismic loadings, are derived on the basis of the lower-bound theorem of limit analysis combined with Rankine's earth pressure theory and the Mohr-Coulomb yield criterion. The generalized active earth pressure coefficients (dimensionless total active thrusts) are presented for use in comprehensive design charts which eliminate the need for tedious and cumbersome graphical diagram process. Charts are developed for rigid earth retaining structures under complex environmental loadings such as the surcharge, pore water pressure and seismic inertia force. An example is presented to illustrate the practical application for the proposed coefficient charts.

Effect of Tea Polyphenols on the Adhesion of Highly Metastatic Human Lung Carcinoma Cell Lines to Endothelial Cells in Vitro

Zheng, Feng-Jin,Shi, Lin,Yang, Jun,Deng, Xiao-Hui,Wu, Yu-Quan,Yan, Xi-Qing,Huang, Ning Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Aim: Tea polyphenols are known to play roles in critical steps of human lung carcinoma cell metastasis. For understanding the mechanisms whereby they inhibit tumor metastasis, the present study was conducted to investigate their effects on the adhesion of highly metastatic lung carcinoma cell lines (PG cells) to endothelial cells (EC cells) and adhesion molecule expression in vitro. Methods: The expression of CD44 or CD54 in the PG cells was detected by flow cytometry and adhesion of PG cells to EC cells was assessed by confocal microscopy double fluorescence staining. Results: The results showed that tea polyphenols: (1) inhibited the expression of CD44 and CD54, two important adhesion molecules in the PG cells in a dose-dependent manner; (2) significantly blocked the adhesion of PG cells to EC cells not only in a state of rest but also when active; and (3) influenced CD44 and CD54 expression during the adhesion process of PG cells to EC cells. Conclusions: The data indicated that the blocking role of tea polyphenols in the adhesion of PG cells to EC cells is related to CD44 and CD54. The mechanism of tea polyphenol prevention of human lung carcinoma metastasis might be through inhibiting adhesion molecule expression to block cancer cell adhesion.

Reducing undesirable vibrations of planar linkage mechanism with joint clearance

Zheng Feng Bai,Xin Jiang,Fei Li,Ji Jun Zhao,Yang Zhao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.2

An optimization design method is presented to reduce the undesirable vibrations caused by clearance for planar linkage mechanism. A clearance joint is defined and considered a contact/impact force constraint. Contact and impact force models for the clearance joint are established using a normal contact force model based on Hertz model with energy loss and a tangential friction model based on modified Coulomb model with dynamic friction coefficient, respectively. In view of the clearance joint, dynamic equations and optimization method for a planar four-bar mechanism are then presented as an application example. The optimization aims to minimize the maximum absolute acceleration peaks of the mechanism by determining the link lengths of the planar linkage mechanism. Finally, the optimization design is solved by a generalized reduced gradient algorithm. Results show evident decrease in vibration peaks of the mechanism and obvious reduction in the contact forces in the clearance joint, which contribute to a good performance of planar linkage mechanism systems.