Numerical simulation of slit wall effect on the Taylor vortex flow with radial temperature gradient

Dong Liu,Chang-qing Chao,Fang-neng Zhu,Xi-qiang Han,Chengtang Liu 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.4

Numerical simulation was applied to investigate the Taylor vortex flow inside the concentric cylinders with a constant radial temperature gradient. The reliability of numerical simulation method was verified by the experimental results of PIV. The radial velocity and temperature distribution in plain and 12-slit model at different axial locations were compared, and the heat flux distributions along the inner cylinder wall at different work conditions were obtained. In the plain model, the average surface heat flux of inner cylinder increased with the inner cylinder rotation speed. In slit model, the slit wall significantly changed the distribution of flow field and temperature in the annulus gap, and the radial flow was strengthen obviously , which promoted the heat transfer process at the same working condition.

Numerical simulation of slit wall effect on the Taylor vortex flow with radial temperature gradient

Liu, Dong,Chao, Chang-qing,Zhu, Fang-neng,Han, Xi-qiang,Tang, Cheng Korean Society for Fluid machinery 2015 International journal of fluid machinery and syste Vol.8 No.4

Numerical simulation was applied to investigate the Taylor vortex flow inside the concentric cylinders with a constant radial temperature gradient. The reliability of numerical simulation method was verified by the experimental results of PIV. The radial velocity and temperature distribution in plain and 12-slit model at different axial locations were compared, and the heat flux distributions along the inner cylinder wall at different work conditions were obtained. In the plain model, the average surface heat flux of inner cylinder increased with the inner cylinder rotation speed. In slit model, the slit wall significantly changed the distribution of flow field and temperature in the annulus gap, and the radial flow was strengthen obviously, which promoted the heat transfer process at the same working condition.

Expression of hPOT1 in HeLa Cells and the Probability of Gene Variation of hpot1 Exon14 in Endometrial Cancer are Much Higher than in Other Cancers

Liu, Fei,Pu, Xiao-Yun,Huang, Shao-Guang,Xiang, Gui-Ming,Jiang, Dong-Neng,Hou, Gou,Huang, Di-Nan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11

To investigate the expression of hPOT1 in the HeLa cell line and screen point mutations of hpot1 in different tumor tissues a two step osmotic method was used to extract nuclear proteins. EMSA was performed to determine the expression of hPOT1 in the HeLa cell line. PCR was also employed to amplify the exon14 sequence of the hpot1 gene in various of cancer tissues. A SV gel and PCR clean-up system was performed to enrich PCR products. DNAStar was used to analyse the exon14 sequence of the hpot1 gene. hPOT1 was expressed in the HeLa cell line and the signal was gradually enhanced as the amount of extracted nuclear proteins increased. The DNA fragment of exon14 of hpot1 was successfully amplified in the HeLa cell line and all cancer tissues, point mutations being observed in 2 out of 3 cases of endometrial cancer (66.7%) despite the hpot1 sequence being highly conserved. However, the sequence of hpot1 exon14 do not demonstrate point mutations in most cancer tissues. Since hPOT1 was expressed in HeLa cell and the probability of gene point variants was obviously higher in endometrial cancer than other cancers, it may be involved in the pathogenesis of gynecological cancers, especially in cervix and endometrium.

Rapid, Sensitive, and Specific Detection of Clostridium tetani by Loop-Mediated Isothermal Amplification Assay

( Dong Neng Jiang ),( Xiao Yun Pu ),( Jie Hong Wu ),( Meng Li ),( Ping Liu ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.1

Tetanus is a specific infectious disease, which is often associated with catastrophic events such as earthquakes, traumas, and war wounds. The obligate anaerobe Clostridium tetani is the pathogen that causes tetanus. Once the infection of tetanus progresses to an advanced stage within the wounds of limbs, the rates of amputation and mortality increase manifold. Therefore, it is necessary to devise a rapid and sensitive point-of-care detection method for C. tetani so as to ensure an early diagnosis and clinical treatment of tetanus. In this study, we developed a detection method for C. tetani using loop-mediated isothermal amplification (LAMP) assay, wherein the C. tetani tetanus toxin gene was used as the target gene. The method was highly specific and sensitive, with a detection limit of 10 colony forming units (CFU)/ml, and allowed quantitative analysis. While detecting C. tetani in clinical samples, it was found that the LAMP results completely agreed with those of the traditional API 20A anaerobic bacteria identification test. As compared with the traditional API test and PCR assay, LAMP detection of C. tetani is simple and rapid, and the results can be identified through naked-eye observation. Therefore, it is an ideal and rapid point-of-care testing method for tetanus.

Axial slit wall effect on the flow instability and heat transfer in rotating concentric cylinders

Dong Liu,Chang-qing Chao,Ying-ze Wang,Fang-neng Zhu,김형범 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

The slit wall effect on the flow instability and heat transfer characteristics in Taylor-Couette flow was numerically studied by changing the rotating Reynolds number and applying the negative temperature gradient. The concentric cylinders with slit wall are seen in many rotating machineries. Six different models with the slit number 0, 6, 9, 12, 15 and 18 were investigated in this study. The results show the axial slit wall enhances the Taylor vortex flow and suppresses the azimuthal variation of wavy Taylor vortex flow. When negative temperature gradient exists, the results show that the heat transfer augmentation appears from laminar Taylor vortex to turbulent Taylor flow regime. The heat transfer enhancement become stronger as increasing the Reynolds number and slit number. The larger slit number model also accelerates the flow transition regardless of the negative temperature gradient or isothermal condition.

Structural Encounters, Meaning Making, and Self-construction: The Reproduction of Chinese Petitioners from a “Normalization” Perspective

RUICHEN ZHANG,NENG LIU 서울대학교 사회발전연구소 2020 Journal of Asian Sociology Vol.49 No.1

Existing literature on China’s system of petitioning (xinfang) usually takes a perspective of institutional change or social problematization, understanding it as either a malfunctioning institution or an indicator of governance crises. This article utilizes a normalization perspective instead, seeing xinfang as an understandable, even rational practice of specific individuals. Based on participant observations in Dongzhuang, Beijing, and in-depth interviews with petitioners in the neighborhood, this article aims to reveal the social mechanisms involved in the so-called normalized xinfang, suggesting that structure and agency are weaved together in this process of reproducing motives and perceived realities, which then leads to the continuation of xinfang practice. The article contributes to a more comprehensive understanding of how individual petitioners persevere through multiple crises in their encounters with structural socio-political realities via meaning making and self-construction. Our study helps uncover the somehow neglected micro foundation of the macro level dilemma of enduring xinfang in China.

Research on the dispersion of carbon nanotubes and their application in solution-processed polymeric matrix composites: A review

Feng, Tao,Liu, Neng,Wang, Shunjie,Qin, Can,Shi, Shengwei,Zeng, Xueying,Liu, Gang Techno-Press 2021 Advances in nano research Vol.10 No.6

This review highlights and categorizes the approaches for preparation of CNTs dispersion and polymer/CNTs composites via solution-based strategies. Carbon nanotubes (CNTs) demonstrate unique physical and chemical properties, which allow several exciting potential applications in various fields including nanocomposites. Presently, the commercialized application of CNTs is still quite limited due to the formation of CNTs bundles, which significantly degrade the properties. Therefore, well dispersion of CNTs in nanocomposites is quite important, especially for CNTs/polymer composites, as a small amount of CNTs can improve the composite properties dramatically. This article will review the research on the dispersion of CNTs (including covalent and non-covalent functionalization) and the fabrication of CNTs/polymer composites through solution-based strategies by using the CNT dispersions. Moreover, the factors influencing the properties of CNTs/polymer composites will be discussed as well as the future outlook.

Political Struggle, Institutionalization, and the Construction of Workers’ Rights: An Analysis of Textile Workers in Tianjin China, 1927-1936

Su Wu,Neng Liu 서울대학교 사회발전연구소 2021 Journal of Asian Sociology Vol.50 No.3

The sociological approach to the study of “civil rights” advocates that “rights” be regarded as a kind of system and practice and focuses on how it is social generated. This article examines the process in which workers’ rights, as the contractual relationship between the modern state and the worker group, gradually emerged and were reproduced. Based on the perspective of the political process, this article attempts to provide clues to answer this question by examining the political changes in Tianjin China from 1927 to 1936, workers’ organization in the textile industry, and the labor movement. The differentiation of interests and political struggle among political parties had urged all parties to devote themselves to enhancing their own strength through social mobilization, which in turn promoted the standardization of worker-related legislation and institutionalization of worker resistance. Workers’ protests also affected the efficacy of partisan competition strategies. As a result, “workers’ rights” had been continuously confirmed by various subjects participating in the political game as a bargaining chip to achieve specific goals.

A facile method for efficient synergistic oxidation of Fe2+ in phosphorus-sulfur mixed acid system with a mixture of oxygen and ozone

Dong-yan Liu,Wen-bo Lou,Shi-neng Sun,Yang Zhang,Ying Zhang,Shi-li Zheng 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12

The recovery of iron phosphate involves the addition of oxidizer to oxidize Fe2+ in the spent LiFePO4 (LFP)material to Fe3+ and the agent commonly used is hydrogen peroxide (H2O2). Nevertheless, H2O2 has disadvantages ofhigh price, easy decomposition and low utilization efficiency. In this manuscript, a facile method is proposed for efficientsynergistic oxidation of Fe2+ in spent LFP leachate with a mixture of oxygen and ozone. Specifically, we found bythermodynamic computations that the dominant oxidation groups of ozone during oxidation varied with acidity. Theoxidation would produce a large number of iron-phosphate complex groups (Fe3H6(PO4)43+, FeH8(PO4)4 and Fe2HPO44+)in the phosphorus-sulfur mixed acid system, leading to a paradoxical pH drop. The optimized conditions for H2O2 oxidationwere explored. It was determined experimentally that oxidation by gas mixture and O2 belonged to the firstorderand second-order reactions with activation energies of 28.68 kJ/mol and 34.61 kJ/mol, respectively, which wereboth controlled by a mixture of chemical reaction and diffusion. The optimized oxidation method was finally determinedby evaluating the cost and oxidation rate of the oxidizers. The results in this study offer a promising method fornew low-cost and efficient Fe2+ oxidation for industrial production.

Carbon Nanotube Paper as Anode for Flexible Lithium-Ion Battery

Xiaogang Sun,Zhenhong Liu,Neng Li,Xiaoyong Wu,Yanyan Nie,Zhipeng Pang,Lifu Yue,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.11

In this investigation, multiwalled carbon nanotube (MWCNT) paper consists of MWCNTs and cellulose was fabricated by traditional paper-making method. It was applied directly as negative electrode in flexible lithium ion battery to replace ordinary electrode which is combined with anode material and current collector. The electrochemical performances of the as-produced MWCNT paper (AMP) and carbonized MWCNT paper (CMP) were evaluated in this study. The morphology and structure of the MWCNT papers were observed by scanning electron microscopy (SEM). The electrochemical performance of the battery was operated by cell test and electrochemical impedance spectroscopy (EIS) measurement. The charging and discharging results indicated that the CMP behaves with higher capacity than AMP. And the EIS analysis showed that a lower charge transfer resistance can be obtained in the CMP. The excellent electrochemical performance verifies the feasibility of MWCNT papers as a promising candidate for the anode in flexible lithium ion battery.