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.

Arabidopsis thaliana Metallothionein, AtMT2a, Mediates ROS Balance during Oxidative Stress

Wei Zhu,Dong-Xiao Zhao,Qing Miao,Tong-Tong Xue,Xin-Zheng Li,Cheng-Chao Zheng 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6

Cold stress has been shown to induce the production of reactive oxygen species (ROS), which can elicit a potentially damaging oxidative burden on cellular metabolism. Here, the expression of a metallothionein gene (AtMT2a) was upregulated under low temperature and hydrogen peroxide (H2O2) stresses. The Arabidopsis T-DNA insertion mutant, mt2a, exhibited more sensitivity to cold stress compared to WT plants during the seed germination, and H2O2 levels in mt2a mutant were higher than that in WT plants during the cold stress. Synthetic GFP fused to AtMT2a was observed to be localized in cytosol. These results indicated that AtMT2a functions in tolerance against cold stress by mediating the ROS balance in the cytosol. Interestingly, mRNA level of AtMT2a was increased in seedlings of Arabidopsis cat2 mutant after cold treatment compared to WT seedlings, and overexpression of AtMT2a in cat2 could improve CAT activity under chilling stress. Moreover, the enzymatic activity of CAT in mt2a was higher than that in WT plants after cold treatment, suggesting that AtMT2a and CAT might complement each other in antioxidative process potentially in Arabidopsis. Taken together, our results provided a novel insight into the relationship between MTs and antioxidative enzymes in the ROS-scavenging system in plants.

Collapse-resistant performance of a single-story frame assembly and multi-story sub-frame under an internal column-removal scenario

Wei-hui Zhong,Zheng Tan,Li-Min Tian,Bao Meng,Yu-hui Zheng,Shi-chao Daun 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.5

To elucidate the differences in the collapse behavior between a single-story beam-column assembly and multi-story frame, two 1/3-scale two-bay composite frames, including a single-story composite beam–column assembly and a three-story composite sub-frame, were designed and quasi-statically tested. The load–displacement responses, failure modes, and internal force development of the two frames were analyzed and compared in detail. Furthermore, the resistance mechanisms of the two specimens were explored, and the respective contributions of different load-resisting mechanisms to the total resistances were quantitatively separated to gain deeper insights. The experimental tests indicated that Vierendeel action was present in the two-dimensional multi-story frames, which led to an uneven internal force distribution among the three stories. The collapse resistance of TSDWA-3S in the flexural stage was not significantly increased by the structural redundancy provided by the additional story, as compared to that of TSDWA-1S. Although the development of the load response was similar in the two specimens at flexural stage, the collapse mechanisms of the multi-story composite frame were much more complicated than those of the single-story beam–column assembly, and the combined action between stories was critical in determining the internal force redistribution and rebalancing of the remaining structure.

Scanning Tunneling Microscopy Studies of the in Desorption Process on the In/Si(111) Surface

Zheng Wei,Geunseop Lee,Heechul Lim 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2

Isothermal desorption of In atoms from the well-ordered In/Si(111) surface were studied by using ultra-high-vacuum scanning tunneling microscopy (STM). At a fixed temperature of 520℃, continuous desorption of the In adatoms from the √31×√31/√3×√3 surface induced a phase transformation into the 7×7 surface. During the desorption process, an intermediate√3×√3 surface with high concentration of substitute Si atoms was formed. The concentration of the substitutional Si adatoms in the √3×√3 regions was found to be as high as 30%. On the 7×7 surface, In atoms substituted for some Si adatoms with a preference for the edge sites compared to the corner sites. However, the population ratios between the two types of adsorption sites were not the same for the faulted and the unfaulted half unit cells. The preference for the edge site over the corner site in the unfaulted half unit cell was found to be about two times higher than that in the faulted half unit cell. Isothermal desorption of In atoms from the well-ordered In/Si(111) surface were studied by using ultra-high-vacuum scanning tunneling microscopy (STM). At a fixed temperature of 520℃, continuous desorption of the In adatoms from the √31×√31/√3×√3 surface induced a phase transformation into the 7×7 surface. During the desorption process, an intermediate√3×√3 surface with high concentration of substitute Si atoms was formed. The concentration of the substitutional Si adatoms in the √3×√3 regions was found to be as high as 30%. On the 7×7 surface, In atoms substituted for some Si adatoms with a preference for the edge sites compared to the corner sites. However, the population ratios between the two types of adsorption sites were not the same for the faulted and the unfaulted half unit cells. The preference for the edge site over the corner site in the unfaulted half unit cell was found to be about two times higher than that in the faulted half unit cell.

Positioning Single Sn Adatoms on the Ge(111)-c(2 X 8) Surface by Scanning Tunneling Microscopy

Zheng Wei 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.II

A scanning tunneling microscope operated at room temperature is used to position single substitutional Sn adatoms to the selected area on the Ge(111)-c($2\times8$) surface. Due to the strong attractive interaction between the tip and the surface, two different manipulation modes are demonstrated: In one mode, Sn adatoms far away from the tip can diffuse to the selected adatom sites under the tip one by one; the other mode involves a concerted shift of a Sn chain due to the positioning procedure.

Colorectal Cancer Incidence and Mortality in China, 2010

Zheng, Zhao-Xu,Zheng, Rong-Shou,Zhang, Si-Wei,Chen, Wan-Qing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19

Background: The National Central Cancer Registry of China (NCCR) affiliated to the Bureau of Disease Control, National Health and Family Planning Commission of China is responsible for cancer surveillance in the entire country. Cancer registration data from each local registry located in each province are collected by NCCR annually to be analyzed and published to provide useful information for policy makers and cancer researchers. Materials and Methods: Until 1st June, 2013, 219 population-based cancer registries submitted data of 2010 to the National Central Cancer Registry of China covering about 207,229,403 population, and 145 cancer registries were selected after quality evaluation for this study. Colorectal cancer cases were selected from the database according to ICD-10 coded as "C18-C20". We calculated the crude incidence and mortality rates by sex, age groups and location (urban/rural). The China population in 2000 and Segi's population were used as standardized populations for the calculation of age-standardized rates. The 6th National Population Census data of China was used to combined with the cancer registries' data to estimate the colorectal cancer burden in China in 2010. Results: Colorectal cancer was the sixth most common cancer in China. It was estimated that there were 274,841 new cases diagnosed in 2010 (157,355 in males and 117,486 in females), with the crude incidence rate of 20.1/100,000, highest in males in urban areas. Age-standardized rates by China standard population of 2000 (ASRcn) and World standard population (Segi's population, ASRwld) for incidence were 16.1/100,000 and 15.9/100,000 respectively. There were 132,110 cases estimated to have died from colorectal cancer in China in 2010 (76,646 men and 55,464 women) with the crude mortality rate of 10.1/100,000. The ASRcn and ASRwld for mortality were 7.55/100,000 and 7.44/100,000 respectively, higher in males and urban areas than in females and rural areas. The incidence and mortality rates increased with age, reaching peaksin the 80-84 year old, and oldest age groups, respectively. Conclusions: Colorectal cancer is one of the most common incident cancers and cause of cancer death in China. Primary and secondary prevention, with attention to a health lifestyle, physical activity and screening should be enhanced in the general population.

Rare Earth as a Potential Preserver for Extending Shelf-life of Minimally Processed ‘Fuji’ Apples

Wei-Wei Zheng,Jeong-Hag Jeong,Ik-Jo Chun 한국원예학회 2008 한국원예학회 기타간행물 Vol.- No.-

Manganese and Iron Interaction: a Mechanism of Manganese-Induced Parkinsonism

Zheng, Wei Korean Environmental Mutagen Society 2003 한국환경성돌연변이·발암원학회지 Vol.23 No.4

Idiopathic Parkinson's disease (IPD) represents a common neurodegenerative disorder. While epidemiological studies have suggested a number of risk factors including age, gender, race, and inherited disorder, the cumulative evidence supports the view that environmental or occupational exposure to certain chemicals may contribute to the initiation and progress of Parkinsonism. More recently, clinical and laboratory investigations have led to the theory that dysregulation of iron, an essential metal to body function, may underlie IPD by initiating free radical reaction, diminishing the mitochondrial energy production, and provoking the oxidative cytotoxicity. The participation of iron in neuronal cell death is especially intriguing in that iron acquisition and regulation in brain are highly conservative and thus vulnerable to interference from other metals that bear the similar chemical reactivity. Manganese neurotoxicity, induced possibly by altering iron homeostasis, is such an example. In fact, the current interest in manganese neurotoxicology stems from two primary concerns: its clinical symptoms that resemble Parkinson's disease and its increased use as an antiknock agent to replace lead in gasoline. This article will commence with addressing the current understanding of iron-associated neurodegenerative damage. The major focus will then be devoted to the mechanism whereby manganese alters iron homeostasis in brain.

Stability Analysis and Dynamic Output Feedback Control for Nonlinear T-S Fuzzy System with Multiple Subsystems and Normalized Membership Functions

Wei Zheng,Zhi-Ming Zhang,Hong-Bin Wang,Hong-Rui Wang,Peng-Heng Yin 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

This paper addresses the stability analysis and dynamic output-feedback control problems for a class of nonlinear Takagi-Sugeno (T-S) fuzzy systems with multiple subsystems and normalized membership functions. First, the switching control law of the membership function is proposed based on the membership function for the nonlinear T-S fuzzy subsystems. Secondly, the relaxation parameter is introduced into this switching control law to guarantee a minimal dwell time between two consecutive switching. Then, based on the proposed switching control law of the membership function and relaxation parameter, the dynamic output feedback controller with the estimate algorithm is designed to estimate the attraction domain. By introducing the new switched Lyapunov-Krasovskii functional, it can be seen that the solutions of the resultant closed-loop system converge to an adjustable bounded region. Compared with the previous works, the developed controller in this paper is flexible and smooth, which only uses the system output. And the results are further extended to the mobile robot case and the chemical process case. Finally, two simulation examples are performed to show the effectiveness of the theoretical results.

Adaptive Dynamic Output-feedback Control for Chemical Continuous Stirred Tank Reactor System with Nonlinear Uncertainties and Multiple Time-delays

Wei Zheng,Hong-Bin Wang,Shu-Huan Wen,Hong-Rui Wang,Zhi-Ming Zhang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper addresses the dynamic-output-feedback control problem for a class of nonlinear system with nonlinear uncertainties and multiple time-delays. Compared with the previous work, the time delay parameters of the system are both multiple and time-varying, and the results are further extended to the chemical continuous stirred tank reactor (CSTR) case. First, the system is decomposed into two subsystems based on the output and input matrix. Secondly, a dynamic compensator is designed for the first subsystem, and the output feedback controller is further employed based on the second subsystem and the compensator. Moreover, by using the introduced LyapunovKrasovskii functional, it can be seen that the solutions of the resultant closed-loop system converge to an adjustable bounded region. In this paper, the uncertainties are in the nonlinear form and bounded by nonlinear functions with unknown gains. And the control design conditions are relaxed because of the developed dynamic compensator. Finally, the simulations for a chemical (CSTR) case are performed to show the effectiveness of the main results.