Numerical Study of Important Factors for a Vortex Shedder using Automated Design Cycle

He Xu,Su Myat Nyein 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.3

The good performance of a vortex shedder is defined by strong and stable vortex generated under the condition of most linearity in Strouhal number and low power loss. In this paper, the flow past a bluff body of circular cylinder with a slit normal to the flow has been analyzed focusing on drag coefficient, linearity of Strouhal number and flow resistance (K-factor). The ANSYS/FLUENT package is used for flow simulation and the integration method of computational code to iSIGHT platform is employed for automated design cycle. This study results the design with (0.20~0.267) blockage ratio and 0.10 slit ratio as the best shedder for vortex flowmeter and this results are in well agreement with the experiment. As the combination of GAMBIT, FLUENT, and iSIGHT substitutes the design parameters automatically according to the input data, this method designs effectively the vortex shedder with less design cycle time and low manufacturing cost eliminating the human intervention bottleneck.

Enhanced Thermal and Mechanical Properties of Lignin/Polypropylene Wood-Plastic Composite by Using Flexible Segment-Containing Reactive Compatibilizer

Xu Xu,Jinhong Yu,Zihai He,Shaorong Lu,Dong Guo 한국고분자학회 2014 Macromolecular Research Vol.22 No.10

A reactive compatibilizer containing flexible segment (RCFS) was synthesized and characterized by Fouriertransform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The RCFS was used as acompatibilizer for the preparation of lignin/polypropylene (PP) wood plastic composites, and the effect of the RCFSon the properties of composites (e.g., mechanical properties, thermal properties, crystal structure, and morphology)were investigated in detail. Experimental results indicated that the lignin/PP composite displayed the best performancewith the addition of 2 wt% RCFS. Its impact strength, flexural strength, and modulus were 56.8%, 37.3%,and 20.6%, respectively, which are higher than those of the untreated composites. Moreover, RCFS treatment couldalso increase the thermal stability, crystallization rate, and degree of crystallinity of lignin/PP composites.

Refolding Behavior of Urea-Induced Denaturation Collagen

Xu Wei,Yanqiu Zhao,Jingjing Zheng,Qin Cao,Sheng Li,Lang He,Benmei Wei,Juntao Zhang,Chengzhi Xu,Haibo Wang 한국고분자학회 2021 Macromolecular Research Vol.29 No.6

Exploration of the denaturation and refolding of natural collagen is important for the application of collagen and its denatured products. In this study, using urea as a denaturant, we prepared a denatured natural collagen product and analyzed its structural changes. The denaturation treatment severely destroyed the triple helix conformation of collagen, but had no significant effect on the primary structure of its α chains or the covalent cross-linking between α chains. Next, we observed the refolding behavior of the denatured collagen by removing urea through dialysis. We found that the denatured collagen products from different sources (grass carp skin, bovine tendon) all showed a reconstruction of the triple helix conformation up to 60-75% of the value of natural collagen during the refolding process. The telopeptide did not significantly promote triple helix reconstruction. In conclusion, the reconstruction of the α chains did not perfectly occur in a “head-to-head, tail-to-tail” manner in refolded collagen, as each α chain was participating in the reconstruction of multiple triple helix domains. The refolded collagen still had weak self-assembly ability and formed a unique network-like structure containing small interlaced and closely combined fibers, which shows favorable cell compatibility and potential applications.

The Impact of Channel on Product Confirmation Rates: A Comparative Analysis of PC and Mobile

XU HE 한국지능정보시스템학회 2023 한국지능정보시스템학회 학술대회논문집 Vol.2023 No.5

Model predictive control strategies for protection of structures during earthquakes

Xu, Long-He,Li, Zhong-Xian Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.2

This paper presents a theoretical study of a model predictive control (MPC) strategy employed in semi-active control system with magnetorheological (MR) dampers to reduce the responses of seismically excited structures. The MPC scheme is based on a prediction model of the system response to obtain the control actions by minimizing an objective function, which can compensate for the effect of time delay that occurred in real application. As an example, a 5-story building frame equipped with two 20 kN MR dampers is presented to demonstrate the performance of the proposed MPC scheme for addressing time delay and reducing the structural responses under different earthquakes, in which the predictive length l = 5 and the delayed time step d = 10, 20, 40, 60, 100 are considered. Comparison with passive-off, passive-on, and linear quadratic Gaussian (LQG) control strategy indicates that MPC scheme exhibits good control performance similar to the LQG control strategy, both have better control effectiveness than two passive control methods for most cases, and the MPC scheme used in semi-active control system show more effectiveness and robustness for addressing time delay and protecting structures during earthquakes.

Inpatients' Knowledge about Primary Liver Cancer and Hepatitis

He, Wen-Jing,Xu, Ming-Yan,Xu, Rui-Rui,Zhou, Xiao-Qiong,Ouyang, Jun-Jie,Han, Hui,Chen, Geng-Zhen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Objective: To assess the level of an inpatient population's awareness about hepatitis and primary liver cancer (PLC), the most common type of which is hepatocellular carcinoma (HCC), and then to initiate education of this group. Methods: A survey was conducted with 1300 participants within the inpatient unit in representative tertiary hospitals in the Chaoshan area of China. Structured questionnaires contained demographic data and statements about different aspects of liver cancer and hepatitis. The questionnaires were completed by trained medical practitioners after they had conducted the interviews. Results: One way ANOVA showed that the sample population lacked adequate knowledge about HCC and hepatitis. Stepwise multiple regression analysis demonstrated that the participant's level of education had the greatest impact on their total knowledge score when other variables remained constant. Conclusions: The study demonstrated: a general lack of awareness amongst the participants about the preventative strategies, and the management options available for people with primary liver cancer and hepatitis; education level was an important factor affecting knowledge levels. The demonstrated deficiencies in people's knowledge about hepatitis and HCC, and their lack of subsequent protective behaviours are likely to play an important role in HCC and hepatitis transmission or prevention.

Preparation of HMX by Catalytic Nitrolysis of DPT in AIL-N₂O₅-HNO₃ System

He, Zhi-Yong,Luo, Jun,Lu, Chun-Xu,Wang, Ping,Xu, Rong,Li, Jin-Shan Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.8

Direct nitrolysis of 3,7-dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT) is a feasible way to synthesize HMX, and it has multiple practical applications. In this paper, a new nitrolysis process involving the use of an $N_2O_5-HNO_3$ system catalyzed by acidic ionic liquids (AILs) was developed. The results show that [$Et_3NH$]TsO was the best catalyst among the 28 AILs used and that HMX was formed at a higher yield of 61%, compared to 45% without any AIL. Moreover, with the addition of $N_2O_5$, the yield was further increased to a maximum value of 69%. The AILs were also efficiently recovered by simple extractions without any apparent loss of catalytic activity, even after five runs.

Behavior and molecular physiology of nurses of worker and queen larvae in honey bees (Apis mellifera)

Xu Jiang He,Liu Qing Tian,AndrewB. Barron,Cui Guan,Hao Liu,Xiaobo Wu,Zhi Jiang Zeng 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.4

In a honey bee colony, worker bees rear a newqueen by providing herwith a larger cell inwhich to develop and alarge amount of richer food (royal jelly). Royal jelly and worker jelly (fed to developing worker larvae) differ interms of sugar, vitamin, protein and nucleotide composition. Here we examined whether workers attendingqueen andworker larvae are separate specialized sub-castes of the nurse bees.We collected nurse bees attendingqueen larvae (AQL) and worker larvae (AWL) and compared gene expression profiles of hypopharyngeal glandtissues, using Solexa/Illumina digital gene expression tag profiling (DGE). Significant differences in gene expressionwere found that included a disproportionate number of genes involved in glandular secretion and royal jellysynthesis. However behavioral observations showed that thesewere not two entirely distinct populations. Nurseworkers were observed attending both worker larvae and queen larvae, and there was no evidence of a specializedgroup of workers that preferentially or exclusively attended developing queens. Nevertheless, AQL attendedlarvaemore frequently compared toAWL, suggesting that nurses sampled attending queen larvaemay have beenthe most active nurses. This study serves as another example of the relationship between differences in gene expressionand behavioral specialisation in honey bees.

Enhance Safety of Telecare Medicine Information System With A RFID-based Authentication Scheme

1He Jialian,Xu Zhiqiang,Xu Xiaoke 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.8

Medication Safety is an important issue for patients. Telecare medicine information system using RFID technology is used to reduce the medication errors and improve the patient safety. In this paper, we show the weaknesses of Keerti Srivastava et al.’s authentication scheme. In order to enhance medication safety for patients, we propose a new lightweight RFID authentication scheme based on dynamic ID. This scheme only requires O(1) work to identify and authenticate a tag in the backend server, so it is practical, secure and efficient for health care domain.

Effects of Multiple-target Anti-microRNA Antisense Oligodeoxyribonucleotides on Proliferation and Migration of Gastric Cancer Cells

Xu, Ling,Dai, Wei-Qi,Xu, Xuan-Fu,Wang, Fan,He, Lei,Guo, Chuan-Yong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Backgrounds: To investigate the inhibiting effects of multi-target anti-microRNA antisense oligonucleotide (MTg-AMOs) on proliferation and migration of human gastric cancer cells. Methods: Single anti-microRNA antisense oligonucleotides (AMOs) and MTg-AMOs for miR-221, 21, and 106a were designed and transfected into SGC7901, a gastric cancer cell line, to target the activity of these miRNAs. Their expression was analyzed using stem-loop RT-PCR and effects of MTg-AMOs on human gastric cancer cells were determined using the following two assay methods: CCK8 for cell proliferation and transwells for migration. Results: In the CCK-8 cell proliferation assay, $0.6{\mu}mol/L$ was selected as the preferred concentration of MTg-AMOs and incubation time was 72 hours. Under these experimental conditions, MTg-AMOs demonstrated better suppression of the expression of miR-221, miR-106a, miR-21 in gastric cancer cells than that of single AMOs (P = 0.014, 0.024; 0.038, respectively). Migration activity was also clearly decreased as compared to those in randomized and blank control groups ($28{\pm}4$ Vs $54{\pm}3$, P <0.01; $28{\pm}4$ Vs $59{\pm}4$, P < 0.01). Conclusions: MTg-AMOs can specifically inhibit the expression of multiple miRNAs, and effectively antagonize proliferation and migration of gastric cancer cells promoted by oncomirs.