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Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle

Yi RUI, Nicholas de BATTISTA, Cedric KECHAVARZI, Xiaomin XU, Mei YIN

《结构与土木工程前沿（英文）》 2021年 第15卷 第1期   页码 167-176 doi: 10.1007/s11709-020-0581-z

摘要： In this paper, we present an application of distributed fiber optic sensor (DFOS) technology to measure the strain of a continuous flight auger (CFA) test pile with a central reinforcement bar bundle, during a static load test carried out in London. Being distributed in nature, DFOS gives much more information about the pile performance as compared to traditional point sensors, such as identifying cross-sectional irregularities or other anomalies. The strain profiles recorded along the depth of the piles from the DFOS were used to calculate pile deformation (contraction), shaft friction, and tip resistance under various loads. Based on this pile load test, a finite element (FE) analysis was performed using a one-dimensional nonlinear load-transfer model. Calibrated by the shaft friction and tip resistance derived from the monitored data, the FE model was able to simulate the pile and soil performance during the load testing with good accuracy. The effect of the reinforcement cage and central reinforcement bar bundle were investigated, and it was found that the addition of a reinforcement cage would reduce the pile settlement by up to 20%.

关键词： continuous flight auger pile     static load test     central reinforcement bar bundle     distributed fiber optic sensor     finite element     load transfer    

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seven cases of critical COVID-19 with early noninvasive–invasive sequential ventilation algorithm and bundle

Mian Peng, Xueyan Liu, Jinxiu Li, Di Ren, Yongfeng Liu, Xi Meng, Yansi Lyu, Ronglin Chen, Baojun Yu, Weixiong Zhong

《医学前沿（英文）》 2020年 第14卷 第5期   页码 674-680 doi: 10.1007/s11684-020-0796-3

摘要： We report the clinical and laboratory findings and successful management of seven patients with critical coronavirus disease 2019 (COVID-19) requiring mechanical ventilation (MV). The patients were diagnosed based on epidemiological history, clinical manifestations, and nucleic acid testing. Upon diagnosis with COVID-19 of critical severity, the patients were admitted to the intensive care unit, where they received early noninvasive–invasive sequential ventilation, early prone positioning, and bundle pharmacotherapy regimen, which consists of antiviral, anti-inflammation, immune-enhancing, and complication-prophylaxis medicines. The patients presented fever ( = 7, 100%), dry cough ( = 3, 42.9%), weakness ( = 2, 28.6%), chest tightness ( = 1, 14.3%), and/or muscle pain ( = 1, 14.3%). All patients had normal or lower than normal white blood cell count/lymphocyte count, and chest computed tomography scans showed bilateral patchy shadows or ground glass opacity in the lungs. Nucleic acid testing confirmed COVID-19 in all seven patients. The median MV duration and intensive care unit stay were 9.9 days (interquartile range, 6.5–14.6 days; range, 5–17 days) and 12.9 days (interquartile range, 9.7–17.6 days; range, 7–19 days), respectively. All seven patients were extubated, weaned off MV, transferred to the common ward, and discharged as of the writing of this report. Thus, we concluded that good outcomes for patients with critical COVID-19 can be achieved with early noninvasive–invasive sequential ventilation and bundle pharmacotherapy.

关键词： COVID-19     noninvasive–invasive sequential ventilation     bundle pharmacotherapy    

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Simulation of cross-flow-induced vibration of tube bundle by surface vorticity method

WANG Fenghao, JIANG Gedong, Lin John Zhang

《能源前沿（英文）》 2008年 第2卷 第3期   页码 243-248 doi: 10.1007/s11708-008-0049-7

摘要： A fluid-structure interaction model based on Surface Vorticity Method (SVM) was used to study flow-induced vibrations of tube bundles in medium space ratio. The flow-induced vibrations of four tubes in a rotated square and a staggered tube bundle in three-row and five-column arrangements were simulated in the high sub-critical Reynolds number () range. The results on fluid forces, tube responses and vorticity maps were presented. The vorticity maps of the four rotated-square tubes changed dramatically when the rigid tubes were replaced by the flexible tubes. From the vorticity maps and vibration responses of the staggered tube bundle of different structural parameters, it was found that with the decrease of tube natural frequency, the maximal vibration response moved from the third row to the first. The results also showed that when more flexible tubes are used, the flow pattern changed drastically and the fluid-structure interaction imposed a dominant impact on the flow.

关键词： dominant     sub-critical Reynolds     staggered     Vorticity     three-row    

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Ultrasonic measurement of tie-bar stress for die-casting machine

《机械工程前沿（英文）》 doi: 10.1007/s11465-021-0663-1

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Seismic behavior experimental study of frame joints with special-shaped column and dispersed steel bar

Shuchun LI, Bo DIAO, Youpo SU,

《结构与土木工程前沿（英文）》 2009年 第3卷 第4期   页码 378-383 doi: 10.1007/s11709-009-0064-8

摘要： To overcome the problem that steel bars are put too close at a flame joint with special-shaped beam and column, mechanical performance of three groups of six RC flame joints with special-shaped (L, T and+) column and dispersed-steel bars-beam on the top floor under cyclic loads were studied. Experimental comparison was conducted between special-shaped (L, T and+) column and normal beams. The cracking load, yielding load, ultimate bearing capacity, failure patterns, and hysteretic properties at joint core area were investigated. The seismic behaviors of the joints with different proportions of dispersed-steel-bar beams were analyzed. The results of experimental analysis indicate that the mechanical and seismic behaviors of frame joints with T-shaped and+-shaped column are nearly not changed when suitable proportion steel bars are dispersed to flange plane. Stiffness degeneration of flame joint with L-shaped column is rather serious due to concrete damage stiffness. Theoretical result indicates that distributing area of the dispersed steel-bar beams in the flange plate should be strictly controlled to avoid anchor destroy.

关键词： beam with dispersed steel bar     flame joints with special-shaped beam and column     seismic behavior     scale of dispersed steel bars    

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Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

《机械工程前沿（英文）》 2013年 第8卷 第2期   页码 160-168 doi: 10.1007/s11465-013-0258-6

摘要：

In this paper, nonlinear dynamic behavior of a four-bar linkage considering clearance is studied. The dynamic model of the linkage with a clearance between coupler and rocker is developed firstly. Then the dynamic equations of this mechanism are solved by a numerical method. According to the calculated response, compliance, force and trajectory of pin in joint bearing are obtained. Effects of clearance magnitude and the relationship between a mechanism with clearance and without clearance are studied. By using Poincare Map, it is proved that strange attractors or chaos exist in the dynamic response. In addition, phenomena of chaos, periodic response and subharmonic response also can be found in the special condition. Bifurcation diagram is used to suggest that bifurcation and fractal phenomena exist in the dynamic response of this mechanism.

关键词： four-bar linkage     chaos     bifurcation     strange attractors     dynamics    

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A low-overhead asynchronous consensus framework for distributed bundle adjustment

Zhuo-hao Liu, Chang-yu Diao, Wei Xing, Dong-ming Lu,roadliu@zju.edu.cn,dcy@zju.edu.cn

《信息与电子工程前沿（英文）》 2020年 第21卷 第10期   页码 1413-1534 doi: 10.1631/FITEE.1900451

摘要： Generally, the (DBA) method uses multiple worker nodes to solve the bundle adjustment problems and overcomes the computation and memory storage limitations of a single computer. However, the performance considerably degrades owing to the introduced by the additional block partitioning step and synchronous waiting. Therefore, we propose a low- consensus framework. A based asynchronous method is proposed to early achieve consensus with respect to the faster worker nodes to avoid waiting for the slower ones. A scene summarization procedure is designed and integrated into the block partitioning step to ensure that clustering can be performed on the small summarized scene. Experiments conducted on public datasets show that our method can improve the worker node utilization rate and reduce the block partitioning time. Also, sample applications are demonstrated using our large-scale culture heritage datasets.
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Multiscale RBF-based central high resolution schemes for simulation of generalized thermoelasticity problems

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 429-455 doi: 10.1007/s11709-018-0483-5

摘要： In this study, average-interpolating radial basis functions (RBFs) are successfully integrated with central high-resolution schemes to achieve a higher-order central method. This proposed method is used for simulation of generalized coupled thermoelasticity problems including shock (singular) waves in their solutions. The thermoelasticity problems include the LS (systems with one relaxation parameter) and GN (systems without energy dissipation) theories with constant and variable coefficients. In the central high resolution formulation, RBFs lead to a reconstruction with the optimum recovery with minimized roughness on each cell: this is essential for oscillation-free reconstructions. To guarantee monotonic reconstructions at cell-edges, the nonlinear scaling limiters are used. Such reconstructions, finally, lead to the total variation bounded (TVB) feature. As RBFs work satisfactory on non-uniform cells/grids, the proposed central scheme can handle adapted cells/grids. To have cost effective and accurate simulations, the multiresolution–based grid adaptation approach is then integrated with the RBF-based central scheme. Effects of condition numbers of RBFs, computational complexity and cost of the proposed scheme are studied. Finally, different 1-D coupled thermoelasticity benchmarks are presented. There, performance of the adaptive RBF-based formulation is compared with that of the adaptive Kurganov-Tadmor (KT) second-order central high-resolution scheme with the total variation diminishing (TVD) property.

关键词： central high resolution schemes     RBFs     higher order accuracy     generalized thermoelasticity     multiresolution-based adaptation    

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A new automatic convolutional neural network based on deep reinforcement learning for fault diagnosis

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0673-7

摘要： Convolutional neural network (CNN) has achieved remarkable applications in fault diagnosis. However, the tuning aiming at obtaining the well-trained CNN model is mainly manual search. Tuning requires considerable experiences on the knowledge on CNN training and fault diagnosis, and is always time consuming and labor intensive, making the automatic hyper parameter optimization (HPO) of CNN models essential. To solve this problem, this paper proposes a novel automatic CNN (ACNN) for fault diagnosis, which can automatically tune its three key hyper parameters, namely, learning rate, batch size, and L2-regulation. First, a new deep reinforcement learning (DRL) is developed, and it constructs an agent aiming at controlling these three hyper parameters along with the training of CNN models online. Second, a new structure of DRL is designed by combining deep deterministic policy gradient and long short-term memory, which takes the training loss of CNN models as its input and can output the adjustment on these three hyper parameters. Third, a new training method for ACNN is designed to enhance its stability. Two famous bearing datasets are selected to evaluate the performance of ACNN. It is compared with four commonly used HPO methods, namely, random search, Bayesian optimization, tree Parzen estimator, and sequential model-based algorithm configuration. ACNN is also compared with other published machine learning (ML) and deep learning (DL) methods. The results show that ACNN outperforms these HPO and ML/DL methods, validating its potential in fault diagnosis.

关键词： deep reinforcement learning     hyper parameter optimization     convolutional neural network     fault diagnosis    

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Degradation of refractory organics in concentrated leachate by the Fenton process: Central composite

Senem Yazici Guvenc, Gamze Varank

《环境科学与工程前沿（英文）》 2021年 第15卷 第1期 doi: 10.1007/s11783-020-1294-1

摘要： Abstract • 90% total COD, 95.3% inert COD and 97.2% UV254 were removed. • High R2 values (over 95%) for all responses were obtained with CCD. • Operational cost was calculated to be 0.238 €/g CODremoved for total COD removal. • Fenton oxidation was highly-efficient method for inert COD removal. • BOD5/COD ratio of leachate concentrate raised from 0.04 to 0.4. The primary aim of this study is inert COD removal from leachate nanofiltration concentrate because of its high concentration of resistant organic pollutants. Within this framework, this study focuses on the treatability of leachate nanofiltration concentrate through Fenton oxidation and optimization of process parameters to reach the maximum pollutant removal by using response surface methodology (RSM). Initial pH, Fe2+ concentration, H2O2/Fe2+ molar ratio and oxidation time are selected as the independent variables, whereas total COD, color, inert COD and UV254 removal are selected as the responses. According to the ANOVA results, the R2 values of all responses are found to be over 95%. Under the optimum conditions determined by the model (pH: 3.99, Fe2+: 150 mmol/L, H2O2/Fe2+: 3.27 and oxidation time: 84.8 min), the maximum COD removal efficiency is determined as 91.4% by the model. The color, inert COD and UV254 removal efficiencies are determined to be 99.9%, 97.2% and 99.5%, respectively, by the model, whereas the total COD, color, inert COD and UV254 removal efficiencies are found respectively to be 90%, 96.5%, 95.3% and 97.2%, experimentally under the optimum operating conditions. The Fenton process improves the biodegradability of the leachate NF concentrate, increasing the BOD5/COD ratio from the value of 0.04 to the value of 0.4. The operational cost of the process is calculated to be 0.238 €/g CODremoved. The results indicate that the Fenton oxidation process is an efficient and economical technology in improvement of the biological degradability of leachate nanofiltration concentrate and in removal of resistant organic pollutants.

关键词： Concentrated leachate     Fenton oxidation     Central composite design     Biodegradability     Inert COD    

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Modeling of dynamic response of poroelastic soil layers under wave loading

Mehmet Bar?? Can üLKER

《结构与土木工程前沿（英文）》 2014年 第8卷 第1期   页码 1-18 doi: 10.1007/s11709-014-0233-2

摘要： In this paper, the dynamic response of saturated and layered soils under harmonic waves is modeled using the finite element method. The numerical results are then verified by corresponding analytical solutions which are also developed by the author. The equations governing the dynamics of porous media are written in their fully dynamic form and possible simplifications are introduced based on the presence of inertial terms associated with solid and fluid phases. The response variations are presented in terms of pore water pressure and shear stress distributions within the layers. It is determined that a set of non-dimensional parameters and their respective ratios as a result of layering play a major role in the dynamic response.

关键词： dynamic response of soils     coupled flow-deformation     finite elements     analytical solution     harmonic waves    

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experimental study of mechanical properties on steel sheet glass fiber reinforced polymer composite bar

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 834-850 doi: 10.1007/s11709-021-0743-7

摘要： The concept of steel sheet glass fiber reinforced polymer (GFRP) composite bar (SSGCB) was put forward. An optimization plan was proposed in the combined form of SSGCB. The composite principle, material selection, and SSGCB preparation technology have been described in detail. Three-dimensional finite element analysis was adopted to perform the combination form optimization of different steel core structures and different steel core contents based on the mechanical properties. Mechanical tests such as uniaxial tensile, shear, and compressive tests were carried out on SSGCB. Parametric analysis was conducted to investigate the influence of steel content on the mechanical properties of SSGCB. The results revealed that the elastic modulus of SSGCB had improvements and increased with the rise of steel content. Shear strength was also increased with the addition of steel content. Furthermore, the yield state of SSGCB was similar to the steel bar, both of which indicated a multi-stage yield phenomenon. The compressive strength of SSGCB was lower than that of GFRP bars and increased with the increase of the steel core content. Stress-strain curves of SSGCB demonstrated that the nonlinear-stage characteristics of SSGCB-8 were much more obvious than other bars.

关键词： steel sheet GFRP composite bar     combination form     numerical modeling     mechanical properties test     strength    

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Development of a multi-component drug from turmeric using central composite design

Xiaohang ZHANG,Shengnan HAN,Yan LI,Jianlan JIANG

《化学科学与工程前沿（英文）》 2014年 第8卷 第3期   页码 362-368 doi: 10.1007/s11705-014-1439-5

摘要： A methodology to develop multi-component drugs based on traditional Chinese medicines has been developed using central composite design. Several active components from the traditional Chinese medicine turmeric were chosen for use in a multi-component antitumor drug. Response surface methodology based on a central composite design was applied to determine the quantitative composition-activity relationships in order to optimize the amount of each component in the drug. An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to measure the pharmacological activity as the response value. The experimental antitumor activity of the optimum combination was 92.85% in the MTT assay and superior to the activities of each single component. These results demonstrate that response surface methodology based on a central composite design is suitable for the design of multi-component drugs.

关键词： multi-component drug development     central composite design     turmeric     curcuminoids    

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Prevalence of vitamin D deficiency in girls with idiopathic central precocious puberty

null

《医学前沿（英文）》 2018年 第12卷 第2期   页码 174-181 doi: 10.1007/s11684-017-0544-5

摘要：

The relationship between vitamin D deficiency and idiopathic central precocious puberty (ICPP) has been recently documented. In this study, 280 girls diagnosed with ICPP and 188 normal puberty control girls of similar ages were enrolled and retrospectively studied. The ICPP group had significantly lower serum 25-hydroxyvitamin D (25[OH]D) levels than the control group. Furthermore, a nonlinear relationship was found between serum 25[OH]D and ICPP, and a cut-off point for serum 25[OH]D was found at 31.8 ng/ml for ICPP with and without adjusting the different confounding factors. Girls with serum 25[OH]D≥31.8 ng/ml had a lower odds ratio (unadjusted: OR 0.36, 95% CI 0.15 to 0.83, <0.05; height and weight adjusted: OR 0.44, 95% CI 0.18 to 1.08, = 0.072; BMI adjusted: OR 0.36, 95% CI 0.16 to 0.84, <0.05). The ICPP subjects with 25[OH]D deficiency had a higher body mass index (BMI) than the subjects from the two other subgroups. Correlation analysis showed that vitamin D level is correlated with BMI and some metabolic parameters in the ICPP group. Our study suggested that vitamin D status may be associated with ICPP risk and may have a threshold effect on ICPP.

关键词： idiopathic central precocious puberty     threshold effects     vitamin D status    

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Anterior cervical surgery methods for central cord syndrome without radiographic spinal fracture-dislocation

Chengwei JING, Qin FU, Xiaojun XU

《医学前沿（英文）》 2009年 第3卷 第1期   页码 45-48 doi: 10.1007/s11684-009-0019-4

摘要： This study was aimed to explore the anterior cervical surgery methods to treat central cord syndrome without radiographic spinal fracture-dislocation (CCSWORFD), retrospectively analyze the cases of CCSWORFD, and evaluate the curative effect of anterior cervical surgery methods for CCSWORFD. Twenty four cases of CCSWORFD (19 males and 5 females), all suffering from cervical hyperextension injury, between 45-68 (average 59) years old, were operated on by anterior cervical surgery methods. Among these, 18 cases had been followed up for 6-24 (average 15) months; 18 cases, who had anterior decompression and plate fixation with titanium mesh bone grafting or iliac bone grafting achieved reliable effects based on the Japanese Orthopedics Association (JOA) evaluation (improved scores of cases with titanium mesh bone grafting, = 2.800, <0.05; improved scores of cases with iliac bone grafting, = 3.270, <0.05), and reliable reconstruction of cervical spine. The two groups obtained the same curative effect ( = 0.470, >0.05) Most of these cases had degeneration of cervical vertebra. The decompression which relieves the oppression to the spinal cord can help lessen edema of the spinal cord, and early fixation for stability of cervical vertebra is better for the recovery of spinal cord injury. Anterior operation with titanium mesh bone grafting or iliac bone grafting are both reliable curative methods for CCSWORFD, and titanium mesh bone grafting can avoid the trauma of the supplying graft. Mesh bone grafting can also shorten hospital stay.

关键词： central cord syndrome     decompression     surgical     titanium mesh    

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标题 作者 时间 类型 操作

Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle

Yi RUI, Nicholas de BATTISTA, Cedric KECHAVARZI, Xiaomin XU, Mei YIN

期刊论文

seven cases of critical COVID-19 with early noninvasive–invasive sequential ventilation algorithm and bundle

Mian Peng, Xueyan Liu, Jinxiu Li, Di Ren, Yongfeng Liu, Xi Meng, Yansi Lyu, Ronglin Chen, Baojun Yu, Weixiong Zhong

期刊论文

Simulation of cross-flow-induced vibration of tube bundle by surface vorticity method

WANG Fenghao, JIANG Gedong, Lin John Zhang

期刊论文

Ultrasonic measurement of tie-bar stress for die-casting machine

期刊论文

Seismic behavior experimental study of frame joints with special-shaped column and dispersed steel bar

Shuchun LI, Bo DIAO, Youpo SU,

期刊论文

Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

期刊论文

A low-overhead asynchronous consensus framework for distributed bundle adjustment

Zhuo-hao Liu, Chang-yu Diao, Wei Xing, Dong-ming Lu,roadliu@zju.edu.cn,dcy@zju.edu.cn

期刊论文

Multiscale RBF-based central high resolution schemes for simulation of generalized thermoelasticity problems

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI

期刊论文

A new automatic convolutional neural network based on deep reinforcement learning for fault diagnosis

期刊论文

Degradation of refractory organics in concentrated leachate by the Fenton process: Central composite

Senem Yazici Guvenc, Gamze Varank

期刊论文

Modeling of dynamic response of poroelastic soil layers under wave loading

Mehmet Bar?? Can üLKER

期刊论文

experimental study of mechanical properties on steel sheet glass fiber reinforced polymer composite bar

期刊论文

Development of a multi-component drug from turmeric using central composite design

Xiaohang ZHANG,Shengnan HAN,Yan LI,Jianlan JIANG

期刊论文

Prevalence of vitamin D deficiency in girls with idiopathic central precocious puberty

null

期刊论文

Anterior cervical surgery methods for central cord syndrome without radiographic spinal fracture-dislocation

Chengwei JING, Qin FU, Xiaojun XU

期刊论文