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Untethered quadrupedal hopping and bounding on a trampoline

Boxing WANG, Chunlin ZHOU, Ziheng DUAN, Qichao ZHU, Jun WU, Rong XIONG

《机械工程前沿（英文）》 2020年 第15卷 第2期   页码 181-192 doi: 10.1007/s11465-019-0559-5

摘要： For quadruped robots with springy legs, a successful jump usually requires both suitable elastic parts and well-designed control algorithms. However, these two problems are mutually restricted and hard to solve at the same time. In this study, we attempt to solve the problem of controller design with the help of a robot without any elastic mounted parts, in which the untethered robot is made to jump on a trampoline. The differences between jumping on hard surfaces with springy legs and jumping on springy surfaces with rigid legs are briefly discussed. An intuitive control law is proposed to balance foot contact forces; in this manner, excessive pitch oscillation during hopping or bounding can be avoided. Hopping height is controlled by tuning the time delay of the leg stretch. Together with other motion generators based on kinematic law, the robot can perform translational and rotational movements while hopping or bounding on the trampoline. Experiments are conducted to validate the effectiveness of the proposed control framework.

关键词： hopping and bounding gait     compliant mechanism     compliant contact     balance control strategy     legged locomotion control     quadruped robot    

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Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 162-172 doi: 10.1007/s11705-009-0267-5

摘要： Bubble columns are widely used in chemical and biochemical processes due to their excellent mass and heat transfer characteristics and simple construction. However, their fundamental hydrodynamic behaviors, which are essential for reactor scale-up and design, are still not fully understood. To develop design tools for engineering purposes, much research has been carried out in the area of computational fluid dynamics (CFD) modeling and simulation of gas-liquid flows. Due to the importance of the bubble behavior, the bubble size distribution must be considered in the CFD models. The population balance model (PBM) is an effective approach to predict the bubble size distribution, and great efforts have been made in recent years to couple the PBM into CFD simulations. This article gives a selective review of the modeling and simulation of bubble column reactors using CFD coupled with PBM. Bubble breakup and coalescence models due to different mechanisms are discussed. It is shown that the CFD-PBM coupled model with proper bubble breakup and coalescence models and interphase force formulations has the ability of predicting the complex hydrodynamics in different flow regimes and, thus, provides a unified description of both the homogeneous and heterogeneous regimes. Further study is needed to improve the models of bubble coalescence and breakup, turbulence modification in high gas holdup, and interphase forces of bubble swarms.

关键词： bubble column     computational fluid dynamics     bubble breakup and coalescence     population balance model     bubble size distribution    

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Gut microbial balance and liver transplantation: alteration, management, and prediction

null

《医学前沿（英文）》 2018年 第12卷 第2期   页码 123-129 doi: 10.1007/s11684-017-0563-2

摘要：

Liver transplantation is a conventional treatment for terminal stage liver diseases. However, several complications still hinder the survival rate. Intestinal barrier destruction is widely observed among patients receiving liver transplant and suffering from ischemia–reperfusion or rejection injuries because of the relationship between the intestine and the liver, both in anatomy and function. Importantly, the resulting alteration of gut microbiota aggravates graft dysfunctions during the process. This article reviews the research progress for gut microbial alterations and liver transplantation. Especially, this work also evaluates research on the management of gut microbial alteration and the prediction of possible injuries utilizing microbial alteration during liver transplantation. In addition, we propose possible directions for research on gut microbial alteration during liver transplantation and offer a hypothesis on the utilization of microbial alteration in liver transplantation. The aim is not only to predict perioperative injuries but also to function as a method of treatment or even inhibit the rejection of liver transplantation.

关键词： gut microbial balance     liver transplantation     ischemia–reperfusion     acute rejection    

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Nonlinear sealing force of a seawater balance valve used in an 11000-meter manned submersible

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0726-y

摘要： Balance valve is a core component of the 11000-meter manned submersible “struggle,” and its sealing performance is crucial and challenging when the maximum pressure difference is 118 MPa. The increasing sealing force improves the sealing performance and increases the system’s energy consumption at the same time. A hybrid analytical–numerical–experimental (ANE) model is proposed to obtain the minimum sealing force, ensuring no leakage at the valve port and reducing energy consumption as much as possible. The effects of roundness error, environmental pressure, and materials on the minimum sealing force are considered in the ANE model. The basic form of minimum sealing force equations is established, and the remaining unknown coefficients of the equations are obtained by the finite element method (FEM). The accuracy of the equation is evaluated by comparing the independent FEM data to the equation data. Results of the comparison show good agreement, and the difference between the independent FEM data and equation data is within 3% when the environmental pressure is 0–118 MPa. Finally, the minimum sealing force equation is applied in a balance valve to be experimented using a deep-sea simulation device. The balance valve designed through the minimum sealing force equation is leak-free in the experiment. Thus, the minimum sealing force equation is suitable for the ultrahigh pressure balance valve and has guiding significance for evaluating the sealing performance of ultrahigh pressure balance valves.

关键词： seawater balance valve     sealing performance     hybrid ANE model     FEM     minimum sealing force equation    

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Quantitative analysis of yield and soil water balance for summer maize on the piedmont of the North China

Jingjing WANG,Feng HUANG,Baoguo LI

《农业科学与工程前沿（英文）》 2015年 第2卷 第4期   页码 295-310 doi: 10.15302/J-FASE-2015074

摘要： The North China Plain (NCP) is a major grain production area in China, but the current winter wheat-summer maize system has resulted in a large water deficit. This water-shortage necessitates the improvement of crop water productivity in the NCP. A crop water model, AquaCrop, was adopted to investigate yield and water productivity (WP) for rain-fed summer maize on the piedmont of the NCP. The data sets to calibrate and validate the model were obtained from a 3-year (2011–2013) field experiment conducted on the Yanshan piedmont of the NCP. The range of root mean square error (RMSE) between the simulated and measured biomass was 0.67–1.25 t·hm , and that of relative error (RE) was 9.4%–15.4%, the coefficient of determination ( ) ranged from 0.992 to 0.994. The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm; and RE and in the range of 1.07%–1.20% and 0.880–0.997, respectively. The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m . The simulated impact of long-term climate (i.e., 1980–2010) and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater, and much lower values elsewhere. The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem, thus a beneficial outcome for both food and ecosystem security can be assured.

关键词： AquaCrop     summer maize     soil water balance     water productivity    

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Mass and heat balance calculations and economic evaluation of an innovative biomass pyrolysis project

Quanyuan WEI, Yongshui QU, Tianwei TAN

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 355-361 doi: 10.1007/s11705-010-0567-9

摘要： Biomass can be converted into flammable gas, charcoal, wood vinegar, wood tar oil and noncombustible materials with thermo-chemical pyrolysis reactions. Many factors influence these processes, such as the properties of the raw materials, and temperature control and these will affect the products that are produced. Based on the data from a straw pyrolysis demonstration project, the mass and heat balance of the biomass pyrolysis process were analyzed. The statistical product and service solutions (SPSS) statistical method was used to analyze the data which were monitored on-site. A cost-benefit analysis was then used to study the viability of commercializing the project. The analysis included net present value, internal rate of return and investment payback period. These results showed that the straw pyrolysis project has little risk, and will produce remarkable economic benefits.

关键词： mass balance     heat balance     biomass pyrolysis     economic benefit    

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Flow and mass balance analysis of eco-bio infiltration system

Marla C. MANIQUIZ, Lee-Hyung KIM, Soyoung LEE, Jiyeon CHOI

《环境科学与工程前沿（英文）》 2012年 第6卷 第5期   页码 612-619 doi: 10.1007/s11783-012-0448-1

摘要： A structured stormwater infiltration system was developed and constructed at a university campus and monitoring of storm events was performed during a one-year operation period. The flow and pollutant mass balances were analyzed and the overall efficiency of the system was assessed. While significant positive correlations were observed among rainfall, runoff and discharge volume ( = 0.93-0.99; <0.05), there was no significant correlations existed between rainfall, runoff, discharge volume and pollutant load. The system was more effective in reducing the runoff volume by more than 50% for small storm events but the difference between the runoff and discharge volume was significant even with rainfall greater than 10 mm. Results showed that the pollutant reduction rates were higher compared to the runoff volume reduction. Average pollutant reduction rates were in the range of 72% to 90% with coefficient of variation between 0.10 and 0.46. Comparable with runoff reduction, the system was more effective in reducing the pollutant load for small storm events, in the range of 80% to 100% for rainfall between 0 and 10 mm; while 65% to 80% for rainfall between 10 and 20 mm. Among the pollutant parameters, particulate matters was highly reduced by the system achieving only a maximum of 25% discharge load even after the entire runoff was completely discharged. The findings have proven the capability of the system as a tool in stormwater management achieving both flow reduction and water quality improvement.

关键词： best management practice     flow balance     low impact development     mass balance     nonpoint source     stormwater runoff    

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Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0676-4

摘要： The control system presently used in shield posture rectification is based on driver experience, which is marginally reliable. The study of the related theory is flawed. Therefore, a decision-making approach for the deviation correction trajectory and posture rectification load for an earth pressure balance (EPB) shield is proposed. A calculation model of posture rectification load of an EPB shield is developed by considering the interactions among the cutter head, shield shell, and ground. The additional position change during the shield attitude correction is highlighted. The posture rectification loads and shield behaviors results can be solved by the proposed method. The influences of the stratum distribution (i.e., bedrock height in the upper-soft and lower-hard strata) on shield behaviors and posture rectification loads are analyzed. Results indicated that the increase of pitch angle in the upper-soft and lower-hard strata causes a sharp rise in vertical displacement. The bedrock height increases the magnitudes of the required posture rectification moments when hr/D > 0.5. For a tunnel with hr/D ≤ 0.5, the variation of hr/D has little effect on the posture rectification moments. Finally, the posture rectifying curves based on the theoretical model are compared with the target ones based on the double circular arc interpolation method. The required results can be obtained regardless of the soil–rock compound stratum distribution. The maximum rectification moment in the rock layer is almost 12.6 times that in the soil layer. Overall, this study provides a valuable reference for moment determination and the trajectory prediction of posture rectification in compound strata.

关键词： additional position change     deviation correction trajectory     earth pressure balance shield     mechanical model     posture rectification    

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Reliability of foam posturography in assessment of postural balance in the patients with vertigo

LIU Bo, KONG Weijia

《医学前沿（英文）》 2008年 第2卷 第4期   页码 361-365 doi: 10.1007/s11684-008-0069-z

摘要： The postural balance is a important aspect of assessment in vestibular rehabilitation therapy. As the computerized dynamic posturography, the foam posturography performed by using foam in posturography is a useful measurement tool for postural balance. Then, the reliability of foam posturography is critical in clinic. To our knowledge, there is no report about the test-retest reliability of foam posturography in the patients with vertigo in China. The foam posturography was taken on the patients with vertigo in stable state and repeated in 3 to 5 days. In the two assessments of test and retest, all subjects stood under 4 sensory conditions, such as firm surface with eyes open (T1), firm surface with eyes closed (T2), foam surface with eyes open (T3) and foam surface with eyes closed (T4) for 30 seconds respectively. The average sway velocity (SV) of center of pressure (COP) under feet of upright standing was recorded as research parameter. The results of patients with vertigo were compared with those of normal subjects. It demonstrated that all normal subjects did not fall in the two assessments. There were 10 of 34 patients with vertigo at least fell one time during the two assessments, and the SVs of these subjects did not taken the analysis of test-retest reliability. The results showed that: (1) The interclass correlation coefficients (ICC) of all 49 subjects including normal subjects and patients without falling were 0.887–0.973 according to the T1–T4 between two assessment. (2) The SVs between the normal subjects and patients were significantly different in the T2 ( = 2.018, = 0.049) and T4 ( = 3.905, < 0.001) in the first assessment and in the T4 ( = 3.715, = 0.001) in the second. And (3) the cases of falling between two assessments were not significant different ( = 0.073, = 0.787) in the patients with vertigo. It is concluded from this study that the foam posturography has high test-retest reliability to assess the postural balance in the patients with vertigo in stable state, indicating the foam posturography can be used as the valid means to assess the improvement of postural balance for patients with vertigo in the vestibular rehabilitation therapy.
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typical pharmaceutical and personal care products in a wastewater treatment plant from Beijing: a mass balance

Jie GAO,Jun HUANG,Weiwei CHEN,Bin WANG,Yujue WANG,Shubo DENG,Gang YU

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 491-501 doi: 10.1007/s11783-016-0837-y

摘要： The fate and removal of pharmaceuticals and personal care products (PPCPs) in wastewater treatment plants (WWTPs) has received great attention during the last decade. Numerous data concerning concentrations in the water phase can be found in the literature, however corresponding data from sludge as well as associated mass balance calculations are very limited. In the present study, the adsorbed and dissolved concentrations of 9 PPCPs were investigated in each unit of a WWTP in Beijing, China. Based on the calculation of mass balance, the relative mass distribution and removal efficiency of each target compound was obtained at each process. The amount of PPCPs entering into the WWTP ranged from 12 g·d to 3848 g·d . Five target compounds (caffeine, chloramphenicol, bezafibrate, clofibric acid, and , -diethyl-meta-toluamide) were effectively removed, with rates of 57%–100%. Negative removal efficiencies were obtained for sulpiride, metoprolol, nalidixic acid, and carbamazepine, ranging from -19% to -79%. PPCPs mainly existed in dissolved form (≥92%) in both the raw influent and the final effluent. The sludge cake carried a much lower amount of PPCPs (17 g·d ) compared with the discharged effluent (402 g·d ). In A /O treatment tanks, the anaerobic and anoxic tanks showed good performance for PPCPs removal, and the amount of adsorbed PPCPs was increased. The results reveal that both the dissolved and the adsorbed phases should be considered when assessing the removal capacity of each A /O tank.

关键词： PPCPs     A2/O     mass balance     removal efficiency     sludge    

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Experimental study on the stratum applicability and mechanisms of bubble–slurry for earth pressure balance

《结构与土木工程前沿（英文）》   页码 1387-1399 doi: 10.1007/s11709-023-0005-y

摘要： Soil conditioning is essential for addressing the stratum applicability problem of earth pressure balance (EPB) shields. Under high water pressures, EPB shields spew water and soil when excavating coarse-grained strata. Typically, foam combined with polymers and slurry is used to solve spewing. However, in current techniques, slurry, foam, and the other agents are mixed with soil separately, their synergistic effect is seldom realized. In this study, an anionic surfactant was used to foam in bentonite slurry to form bubble–slurry to maximize the synergy between bubbles and slurry. The slump, volume stability, and permeability test of bubble–slurry-conditioned sand was conducted to examine the conditioning effect, and the stratum applicability of bubble–slurry was determined from the perspective of permeability. It was found that the conditioning effect of bubble–slurry in coarse gravel soil was excellent and could expand the applicability of EPB shields. The main stabilization mechanism of bubble–slurry is that bentonite particles provide a space barrier for bubbles. And three seepage modes of bubble–slurry-conditioned sand were innovatively defined, and the occurrence conditions of the three seepage modes were analyzed according to the permeability coefficient of sand, initial dynamic shear force of bubble–slurry, and hydraulic gradient.

关键词： EPB shield     bubble–slurry     soil conditioning     stability     permeability    

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时变网络的收敛性及其应用 Research Articles

王庆领

《信息与电子工程前沿（英文）》 2021年 第22卷 第1期   页码 1-140 doi: 10.1631/FITEE.2000160

摘要： 本文分析一类时变网络的收敛性。将收敛性质应用于具有未知控制方向的非线性多智能体系统协同控制问题，并提出一类新的基于Nussbaum型函数的控制策略。若时变网络是准平衡的，则所提控制策略可实现具有未知控制方向的非线性多智能体系统的收敛。所提算法的一个重要特点是，该算法可采用经典的Nussbaum型函数解决控制方向未知且不等同问题。最后，提出一个仿真案例验证所提算法的有效性。

关键词： 时变网络；未知控制方向；Nussbaum型函数；准平衡条件    

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Experimental study on working parameters of earth pressure balance shield machine tunneling in soft ground

ZHU Hehua, LIAO Shaoming, XU Qianwei, ZHENG Qizhen

《结构与土木工程前沿（英文）》 2008年 第2卷 第4期   页码 350-358 doi: 10.1007/s11709-008-0051-5

摘要： Deep sedimentary deposits of soft clays are widely distributed in coastal areas as well as many interior major cities in China. In order to study the stratum adaptability of earth pressure balance (EPB) shield machine tunneling in such types of soft ground, model tests of tunneling excavation, using the running tunnel of the Shanghai Metro Line M8 as a background, are carried out with different over burden ratios, opening rates of cutter head, driving speeds and rotation speeds of screw conveyor. Based on the test results, the interrelationships between chamber pressure and mucking efficiency, mucking rate and driving speed, thrust force and torque are obtained. The influences of tunnel depth, opening rate of cutter head and driving speed on thrust force and torque are revealed. Such findings can not only facilitate establishing relationships between shield working parameters and soil properties, but also serve as a guide for the design and construction of shield tunnel in soft ground.

关键词： construction     different     coastal     conveyor     excavation    

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Push recovery for the standing under-actuated bipedal robot using the hip strategy

Chao LI,Rong XIONG,Qiu-guo ZHU,Jun WU,Ya-liang WANG,Yi-ming HUANG

《信息与电子工程前沿（英文）》 2015年 第16卷 第7期   页码 579-593 doi: 10.1631/FITEE.14a0230

摘要： This paper presents a control algorithm for push recovery, which particularly focuses on the hip strategy when an external disturbance is applied on the body of a standing under-actuated biped. By analyzing a simplified dynamic model of a bipedal robot in the stance phase, it is found that horizontal stability can be maintained with a suitably controlled torque applied at the hip. However, errors in the angle or angular velocity of body posture may appear, due to the dynamic coupling of the translational and rotational motions. To solve this problem, different hip strategies are discussed for two cases when (1) external disturbance is applied on the center of mass (CoM) and (2) external torque is acting around the CoM, and a universal hip strategy is derived for most disturbances. Moreover, three torque primitives for the hip, depending on the type of disturbance, are designed to achieve translational and rotational balance recovery simultaneously. Compared with closed-loop control, the advantage of the open-loop methods of torque primitives lies in rapid response and reasonable performance. Finally, simulation studies of the push recovery of a bipedal robot are presented to demonstrate the effectiveness of the proposed methods.

关键词： Push recovery     Balance control     Bipedal robot     Hip strategy    

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Biodegradation of waste refrigerator polyurethane by mealworms

《环境科学与工程前沿（英文）》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1638-8

摘要：

● Waste refrigerator polyurethane (WRPU) was ingested and biodegraded by mealworms.

关键词： Waste refrigerator polyurethane     Mealworms     Biodegradation     Carbon balance     Gut microorganism    

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标题 作者 时间 类型 操作

Untethered quadrupedal hopping and bounding on a trampoline

Boxing WANG, Chunlin ZHOU, Ziheng DUAN, Qichao ZHU, Jun WU, Rong XIONG

期刊论文

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

期刊论文

Gut microbial balance and liver transplantation: alteration, management, and prediction

null

期刊论文

Nonlinear sealing force of a seawater balance valve used in an 11000-meter manned submersible

期刊论文

Quantitative analysis of yield and soil water balance for summer maize on the piedmont of the North China

Jingjing WANG,Feng HUANG,Baoguo LI

期刊论文

Mass and heat balance calculations and economic evaluation of an innovative biomass pyrolysis project

Quanyuan WEI, Yongshui QU, Tianwei TAN

期刊论文

Flow and mass balance analysis of eco-bio infiltration system

Marla C. MANIQUIZ, Lee-Hyung KIM, Soyoung LEE, Jiyeon CHOI

期刊论文

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

期刊论文

Reliability of foam posturography in assessment of postural balance in the patients with vertigo

LIU Bo, KONG Weijia

期刊论文

typical pharmaceutical and personal care products in a wastewater treatment plant from Beijing: a mass balance

Jie GAO,Jun HUANG,Weiwei CHEN,Bin WANG,Yujue WANG,Shubo DENG,Gang YU

期刊论文

Experimental study on the stratum applicability and mechanisms of bubble–slurry for earth pressure balance

期刊论文

时变网络的收敛性及其应用

王庆领

期刊论文

Experimental study on working parameters of earth pressure balance shield machine tunneling in soft ground

ZHU Hehua, LIAO Shaoming, XU Qianwei, ZHENG Qizhen

期刊论文

Push recovery for the standing under-actuated bipedal robot using the hip strategy

Chao LI,Rong XIONG,Qiu-guo ZHU,Jun WU,Ya-liang WANG,Yi-ming HUANG

期刊论文

Biodegradation of waste refrigerator polyurethane by mealworms

期刊论文