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.

Sparse Structured Non-fragile H∞ Controller Design for Linear Systems

Wei-Wei Che,Guang-Hong Yang,Xiao-Zheng Jin 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.4

This paper presents a study on the problem of designing non-fragile H∞ controllers with sparse structures for linear continuous-time systems. A new algorithm is proposed to define and further design sparse structured controllers. Firstly, sparse structures are specified from a given fully parameterized H∞ controller. Then, a three-step design procedure for non-fragile dynamic output feedback H∞ controllers with the sparse structures is provided. The resulting designs guarantee that the closed-loop system is asymptotically stable and the H∞ performance from the disturbance to the regulated output is less than a prescribed level. A numerical example is given to illustrate the design methods.

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.-

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.

Surface-functionalized Hexagonal Mesoporous Silica Supported 5-(4-Carboxyphenyl)-10,15,20-triphenyl Porphyrin Manganese(III) Chloride and Their Catalytic Activity

Wei-jie Zhang,Pingping Jiang,Ping-bo Zhang,Jia-wei Zheng,Haiyang Li 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

Manganese(III) 5-(4-carboxyphenyl)-10,15,20-triphenyl porphyrin chloride (Mn(TCPP)Cl) was grafted through amide bond on silica zeolite Y (HY), zeolite beta (Hβ) and hexagonal mesoporous silica (HMS). XRD, ICP-AES, N2 physisorption, SEM, TEM, FTIR and thermal analysis were employed to analyse these novel heterogeneous materials. These silica supported catalysts were shown to be used for epoxidation and good shape selectivity was observed. The effect of support structure on catalytic performance was also discussed. The catalytic activity remained when the catalysts were recycled five times. The energy changes about epoxidation of alkenes by NaIO4 and H2O2 were also computationally calculated to explain the different catalytic efficiency.

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.

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.

Cancer Registration in the Peoples Republic of China

Wei, Kuang-Rong,Chen, Wan-Qing,Zhang, Si-Wei,Liang, Zhi-Heng,Zheng, Rong-Shou,Ou, Zhi-Xiong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

The current situation of cancer registration in China was systematically reviewed. So far, cancer registration in China has been making a great progress in the following aspects: the number of cancer registries and covered population have increased dramatically; a registration network has been established and completed gradually; regulations and rules improved remarkably; more attention is being paid by every level of government; a lot of registration software has been created and financial support ensured. However, we are still facing some problems and challenges, such as no stable groups of registrars, shortage of training opportunities, poor data quality, insufficient utilization and lack of multidisciplinary mechanisms, so that the cancer registration system still needs to be enhanced and improved. Along with the development of economy, science and information technology, methods and patterns of cancer registration is changing. It is to be expected that cancer registration will be automatic, nationwide and integrated with community healthcare in the near future.

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.

Surgical Outcomes of Symptomatic Intramedullary Spinal Cord Cavernous Malformations: Analysis of Consecutive Cases in a Single Center

Zheng Cai,Xinjie Hong,Wei Dai,Zhengwei Zhang,Qiang Liang,Xuehua Ding,Wei Sun 대한척추신경외과학회 2023 Neurospine Vol.20 No.3

Objective: Intramedullary spinal cavernous malformations (ISCMs) are rare vascular lesions of the spinal cord with unclear natural history and controversy over treatment. This study aimed to report a series of symptomatic ISCMs underwent microsurgical management to illustrate the natural history, clinical presentation, and surgical outcomes and to evaluate factors associated with hemorrhage events and neurological prognosis. Methods: This single-center retrospective study included 29 consecutive patients with whose demographic, symptomology, imaging, neurological, and surgical data were collected. The risk for hemorrhage events and factors affecting surgical outcomes were retrospectively analyzed. Results: There were 12 female (41.4%) and 17 male patients (58.6%), with an average age of 45.2 years (range, 17–69 years). The mean size of the lesion was 9.7 mm (range, 3–20 mm). Most patients had a bowel or/and bladder dysfunction symptom (n = 11, 37.9%), followed by sensory deficits (n = 5, 17.2%), gait disturbance (n = 5, 17.2%), pain (n = 4, 13.8%), and weakness (n = 4, 13.8%), most (n = 15, 51.7%) with a chronic onset. All patients received total resection without rehemorrhages after surgical resection in follow-up. Sixty-five point five percent patients (n = 19) improved, 13.8% (n = 4) remained stable, 20.7% (n = 6) got worsen. The overall annual hemorrhage risk was 2.1% per patient-year. A total of 27 hemorrhages occurred in the 18 patients, of which rehemorrhage rate increased to 50.0% (n = 9) with a previous history of hemorrhage. Patients with smaller lesion sizes were more likely to have hemorrhage or rehemorrhage events (p = 0.008). Recurrent hemorrhage of the lesions was a risk factor for neurological outcomes (p = 0.016). Conclusion: The risk of rehemorrhage was significantly increased in symptomatic ISCM patients with a previous history of hemorrhage. Rehemorrhage was a risk factor for neurological outcomes. Patients can benefit from microsurgical treatment to avoid rehemorrhage and further neurological deterioration.