A wireless decentralized control experimental platform for vibration control of civil structures

Yan Yu,Luyu Li,Xiaozhi Leng,Gangbing Song,Zhiqiang Liu,Jinping Ou 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.19 No.1

Considerable achievements in developing structural regulators as an important method for vibration control have been made over the last few decades. The use of large quantities of cables in traditional wired control systems to connect sensors, controllers, and actuators makes the structural regulators complicated and expensive. A wireless decentralized control experimental platform based on Wi-Fi unit is designed and implemented in this study. Centralized and decentralized control strategies as sample controllers are employed in this control system. An optimal control algorithm based on Kalman estimator is embedded in the dSPACE controller and the DSP controller. To examine the performance of this control scheme, a three-story steel structure is developed with active mass dampers installed on each floor as the wireless communication platform. Experimental results show that the wireless decentralized control exhibits good control performance and has various potential applications in industrial control systems. The proposed experimental system may become a benchmark platform for the validation of the corresponding wireless control algorithm.

Numerical Simulation on New Conical Spray for Diesel Premixed Charge Compression Ignition

( Li Yan Feng ),( Wu Qiang Long ),( Bao Guo Du ),( Xian Yin Leng ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-

Concerning the difficulty of pre-mixture preparation for diesel HCCI combustion, a new conical spray is proposed. The new conical spray is formed by the combination of multi-hole nozzle and close impingement structure. The new spray has characteristics of high dispersion and acts with flexible penetration in design. Three-dimensional CFD package AVL FIRE 8.2 was used to simulate pre-mixture preparation process with the new conical spray. The effects of combustion chamber shape and impingement structure on pre-mixture quality were analyzed. The calculation results indicate the following conclusions: (1) with the application of new conical spray, fuel impingement and adhesion on piston or liner surface are avoided; (2) combustion chamber shape has crucial effect on pre-mixture homogeneity, which is apparent when start of injection is or later than 60°CA BTDC; (3) compared with other kinds of combustion chamber, deep reentrant combustion chamber performs better on pre-mixture preparation if the start of injection is 60° or 80°CA BTDC; (4) the geometry of impingement orientation structure also affects pre-mixture quality.

<i>MIF</i> allele-dependent regulation of the MIF coreceptor CD44 and role in rheumatoid arthritis

Yoo, Seung-Ah,Leng, Lin,Kim, Bum-Joon,Du, Xin,Tilstam, Pathricia V.,Kim, Kyung Hee,Kong, Jin-Sun,Yoon, Hyung-Ju,Liu, Aihua,Wang, Tian,Song, Yan,Sauler, Maor,Bernhagen, Jurgen,Ritchlin, Christopher T. National Academy of Sciences 2016 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.113 No.49

<P>Fibroblast-like synoviocytes mediate joint destruction in rheumatoid arthritis and exhibit sustained proinflammatory and invasive properties. CD44 is a polymorphic transmembrane protein with defined roles inmatrix interaction and tumor invasion that is also a signaling coreceptor for macrophage migration inhibitory factor (MIF), which engages cell surface CD74. High-expression MIF alleles (rs5844572) are associated with rheumatoid joint erosion, but whether MIF signaling through the CD74/CD44 receptor complex promotes upstream autoimmune responses or contributes directly to synovial joint destruction is unknown. We report here the functional regulation of CD44 by an autocrine pathway in synovial fibroblasts that is driven by high-expression MIF alleles to up-regulate an inflammatory and invasive phenotype. MIF increases CD44 expression, promotes its recruitment into a functional signal transduction complex, and stimulates alternative exon splicing, leading to expression of the CD44v3-v6 isoforms associated with oncogenic invasion. CD44 recruitment into the MIF receptor complex, downstream MAPK and RhoA signaling, and invasive phenotype require MIF and CD74 and are reduced by MIF pathway antagonists. These data support a functional role for high-MIF expression alleles and the two-component CD74/CD44 MIF receptor in rheumatoid arthritis and suggest that pharmacologic inhibition of this pathway may offer a specific means to interfere with progressive joint destruction.</P>

Flexure-Hinges Guided Nano-Stage for Precision Manipulations: Design, Modeling and Control

Peng-Bo Liu,Peng Yan,Zhen Zhang,Tong-Tong Leng 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In this paper, a novel piezoelectric actuator driven nano-stage with bridge type mechanism is studied from the perspectives of design optimization, dynamical modeling, as well as controller synthesis for high precision manipulation purposes. FEM (Finite Element Method) analysis and dynamical modeling are provided to derive the system model including the hysteresis nonlinearity. Considering the complexities of dynamical uncertainties and hysteresis nonlinearity, an active disturbance rejection controller is developed consisting of extended state observer (ESO), state feedback controller and profile generator. With the proposed algorithm, the nonlinear dynamics, system uncertainties and external disturbances can be treated as part of the “total disturbances”, such that the extended state observer can be used to estimate and suppress the effects of these complex dynamics. The proposed control algorithm is deployed in real time implementations on the designed nano-stage, where experimental results demonstrate good control performance in terms of high precision positioning, hysteresis compensation and disturbance rejection.

Hypotensive Effects Induced by Herbal Fomentation at Yongquan Point

YanQing Tong,QiPing Yu,Yan Leng 사단법인약침학회 2012 Journal of Acupuncture & Meridian Studies Vol.5 No.6

Objective: This study aimed at assessing the adequacy of blood pressure (BP) control with the Chinese herbal fomentation at Yongquan point (K1). Method: A total of 51 participants as a group were enrolled. In 10 participants as the subgroup, BP data were compared with those simultaneously recorded from the radial artery of the same side. After the baseline examination, each enrolled patient participated in one session lasting 24 hours, during which Yongquan point (K1) of both sides were fomented with a mixture of Chinese herbs. The technique of 24-hour Ambulatory BP monitoring (ABPM) was repeated at baseline and on the day after the therapy. Results: The systolic and diastolic BP measured intra-arterially during the test were, on average, similar to those measured noninvasively. Patients obtained a 6.0 mmHg reduction for systolic BP and a 4.8 mmHg reduction for diastolic BP during daytime. The rate of adverse events was 2.0% in the group. Conclusion: Our data demonstrated that BP recording by the ABPM method in our study provided a relatively accurate estimate of the average radial BP of the population. So the conclusion, “Chinese herbal fomentation at Yongquan point (K1) of both sides has some hypotensive potentials” was more reliable. Objective: This study aimed at assessing the adequacy of blood pressure (BP) control with the Chinese herbal fomentation at Yongquan point (K1). Method: A total of 51 participants as a group were enrolled. In 10 participants as the subgroup, BP data were compared with those simultaneously recorded from the radial artery of the same side. After the baseline examination, each enrolled patient participated in one session lasting 24 hours, during which Yongquan point (K1) of both sides were fomented with a mixture of Chinese herbs. The technique of 24-hour Ambulatory BP monitoring (ABPM) was repeated at baseline and on the day after the therapy. Results: The systolic and diastolic BP measured intra-arterially during the test were, on average, similar to those measured noninvasively. Patients obtained a 6.0 mmHg reduction for systolic BP and a 4.8 mmHg reduction for diastolic BP during daytime. The rate of adverse events was 2.0% in the group. Conclusion: Our data demonstrated that BP recording by the ABPM method in our study provided a relatively accurate estimate of the average radial BP of the population. So the conclusion, “Chinese herbal fomentation at Yongquan point (K1) of both sides has some hypotensive potentials” was more reliable.

Analysis of Toe Formation in Stress-Concentration Zones on High Rock Slopes

Ke Deng,Ming Chen,Peng Yan,Zhendong Leng,Guangdong Yang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

Toe formation is a phenomenon resulting from unconnected cracks between blastholes,which occurred during blasting excavation of the abutment slot at Baihetan hydropower station. Analysis of crack development has tended not to focus on the high in-situ stress environment at the slope corner. Therefore, this study aimed to explore the toe formation process through theoretical analysis and numerical simulation. Firstly, a three-blasthole model was established to analyze the effects of blasting load and in-situ stress on crack extension. Then, a finite-element model of the abutment slot was built to simulate crack propagationunder different in-situ stress environment. Finally, optimization measures for avoiding toe were proposed. The results demonstrate that cracks grow preferentially in the direction of the maximum tangential tensile stress and are influenced by the blasting load and in-situ stress. On the lateral side of the abutment slot, the crack initiation and extension occur far from the centerline due to the deviation of the maximum tangential tensile stress. The deviation increased as the in-situ stress. Consequently, cracks between blastholes not being able to connect with each other results in toe formation. Increment of the linear density of the charge and optimization of the excavated profile are both effective in reducing the impact of the stress concentration caused by in-situ stress and preventing toe formation.

Bridging therapies to liver transplantation for hepatocellular carcinoma: A bridge to nowhere?

Chun Han Nigel Tan,Yue Yu,Yan Rui Nicholas Tan,Boon Leng Kieron Lim,Shridhar Ganpathi Iyer,Krishnakumar Madhavan,Alfred Wei Chieh Kow 한국간담췌외과학회 2018 Annals of hepato-biliary-pancreatic surgery Vol.22 No.1

Backgrounds/Aims: Liver Transplantation (LT) is a recognized treatment for Hepatocellular Carcinoma (HCC). The role of Bridging Therapies (BT) remains controversial. Methods: From January 2001 to October 2012, 192 patients were referred to the National University Hospital, Singapore for consideration of LT for HCC. Sixty-five patients (33.8%) were found suitable for transplant and were placed on the waitlist. Analysis was performed in these patients. Results: The most common etiology of HCC was Hepatitis B (n=28, 43.1%). Thirty-six patients (55.4%) received BT. Seventeen patients (47.2%) received TACE only, while 10 patients (27.8%) received radiofrequency ablation (RFA) only. The remaining patients received a combination of transarterial chemoembolization (TACE) and RFA. Baseline tumor and patient characteristics were comparable between the two groups. The overall dropout rate was 44.4% and 31.0% in the BT and non-BT groups, respectively (p=0.269). The dropout rate due to disease progression beyond criteria was 6.9% (n=2) in the non-bridged group and 22.2% (n=8) in the bridged group (p=0.089). Thirty-nine patients (60%) underwent LT, of which all patients who underwent Living Donor LT did not receive BT (n=4, 21.1%, p=0.030). The median time to LT was 180 days (range, 20-558 days) in the non-BT group and 291 days (range, 17-844 days) in the BT group (p=0.214). There was no difference in survival or recurrence between the BT and non-BT groups (p=0.862). Conclusions: BT does not influence the dropout rate or survival after LT but it should be considered in patients who are on the waitlist for more than 6 months.

Field measurements of wind pressure on an open roof during Typhoons HaiKui and SuLi

Ruoqiang Feng,Fengcheng Liu,Qi Cai,Guirong Yan,Jiabing Leng 한국풍공학회 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

Full-scale measurements of wind action on the open roof structure of the WuXi grand theater, which is composed of eight large-span free-form leaf-shaped space trusses with the largest span of 76.79 m, were conducted during the passage of Typhoons HaiKui and SuLi. The wind pressure field data were continuously and simultaneously monitored using a wind pressure monitoring system installed on the roof structure during the typhoons. A detailed analysis of the field data was performed to investigate the characteristics of the fluctuating wind pressure on the open roof, such as the wind pressure spectrum, spatial correlation coefficients, peak wind pressures and non-Gaussian wind pressure characteristics, under typhoon conditions. Three classical methods were used to calculate the peak factors of the wind pressure on the open roof, and the suggested design method and peak factors were given. The non-Gaussianity of the wind pressure was discussed in terms of the third and fourth statistical moments of the measured wind pressure, and the corresponding indication of the non-Gaussianity on the open roof was proposed. The result shows that there were large pulses in the time-histories of the measured wind pressure on Roof A2 in the field. The spatial correlation of the wind pressures on roof A2 between the upper surface and lower surface is very weak.When the skewness is larger than 0.3 and the kurtosis is larger than 3.7, the wind pressure time series on roof A2 can be taken as a non-Gaussian distribution, and the other series can be taken as a Gaussian distribution.

Field measurements of wind pressure on an open roof during Typhoons HaiKui and SuLi

Feng, Ruoqiang,Liu, Fengcheng,Cai, Qi,Yan, Guirong,Leng, Jiabing Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

Full-scale measurements of wind action on the open roof structure of the WuXi grand theater, which is composed of eight large-span free-form leaf-shaped space trusses with the largest span of 76.79 m, were conducted during the passage of Typhoons HaiKui and SuLi. The wind pressure field data were continuously and simultaneously monitored using a wind pressure monitoring system installed on the roof structure during the typhoons. A detailed analysis of the field data was performed to investigate the characteristics of the fluctuating wind pressure on the open roof, such as the wind pressure spectrum, spatial correlation coefficients, peak wind pressures and non-Gaussian wind pressure characteristics, under typhoon conditions. Three classical methods were used to calculate the peak factors of the wind pressure on the open roof, and the suggested design method and peak factors were given. The non-Gaussianity of the wind pressure was discussed in terms of the third and fourth statistical moments of the measured wind pressure, and the corresponding indication of the non-Gaussianity on the open roof was proposed. The result shows that there were large pulses in the time-histories of the measured wind pressure on Roof A2 in the field. The spatial correlation of the wind pressures on roof A2 between the upper surface and lower surface is very weak. When the skewness is larger than 0.3 and the kurtosis is larger than 3.7, the wind pressure time series on roof A2 can be taken as a non-Gaussian distribution, and the other series can be taken as a Gaussian distribution.

Peroxopolyoxotungsten-based Ionic Hybrid as a Highly Efficient Recyclable Catalyst for Epoxidation of Vegetable oil with H2O2

Jianghao Wu,Pingping Jiang,Xiaojie Qin,Yuanyuan Ye,Yan Leng 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

A peroxopolyoxotungsten-based ionic hybrid was synthesized by anion-change of peroxopolyoxometalate (POM) PW4O24 3− with dicationic long-chain alkyl imidazolium ionic liquids. The characterization was conducted by FT-IR, TGA, 1H-NMR and CHN Elemental analyses. Its catalytic performance was evaluated by the epoxidation of soybean oil with H2O2 under solvent-free condition, including testing of organic cations influence, catalytic reusability and reaction conditions. The catalyst was proved to be a highly efficient recyclable catalyst for epoxidation of various vegetable oils with H2O2, showing high H2O2 utilization efficiency, high catalytic activity, convenient recovery and good reuse ability.