资源类型

期刊论文 287

年份

2023 28

2022 28

2021 28

2020 14

2019 23

2018 10

2017 10

2016 14

2015 14

2014 15

2013 11

2012 11

2011 6

2010 15

2009 8

2008 17

2007 11

2006 7

2004 2

2002 2

展开 ︾

关键词

复合材料 5

PP 2

力学性能 2

复合镀层 2

流动育龄妇女 2

电沉积 2

组合梁 2

BMI树脂 1

CCS 1

CO2分离 1

EFP 1

HDPE 1

WPC 1

Zn-Fe-SiO2 1

丁醇 1

三峡电站 1

买得起复合材料 1

亚铁氰化铜 1

代数推理 1

展开 ︾

检索范围：

排序： 展示方式：

reduction in sequencing batch biofilm reactor: Performances, mechanisms and comparison of different carriers

Yonglei Wang, Baozhen Liu, Kefeng Zhang, Yongjian Liu, Xuexin Xu, Junqi Jia

《环境科学与工程前沿（英文）》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1077-0

摘要：

Microbial metabolism uncoupling, sludge decay is the main mechanism to promote in situ sludge reduction on this biofilm system.

The main reduction mechanism inside the biofilm is sludge decay in the longitudinal distribution of biofilm.

Mizugakiibacter and Azospira anaerobic fermentation bacterium dominate the FSC organisms indicating the dominant mechanism on the biofilm is sludge decay.

The floating spherical carriers with compound of the polyurethane and two fiber balls can effectively blocking suspended sludge, improving Biofilm formation efficiency significantly.

关键词： In situ sludge reduction     Biofilm     Composite floating spherical carriers     Microbial community     SBBR    

HTML PDF 收藏

Enhanced nitrification in integrated floating fixed-film activated sludge (IFFAS) system using novelclinoptilolite composite carrier

Aoshuang Jing, Tao Liu, Xie Quan, Shuo Chen, Yaobin Zhang

《环境科学与工程前沿（英文）》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1153-0

摘要： Novel carriers with favorable electrophilicity and hydrophilicity were prepared. Novel carriers had the capability of nitrification-enhancing. NH4+-N removal efficiency of IFFAS process rose up to 20% with novel carriers. Nitrosomonadales and Nitrospirales were identified as the functional nitrifiers. The population of Nitrospirales increased by 4.51%. The integrated floating fixed-film activated sludge (IFFAS) process is an ideal preference for nitrification attributing to the longer sludge age for nitrifiers. However, as the core of this process, conventional carriers made of polymer materials usually exhibit negative charge and hydrophobicity on the surface, which is unbeneficial to nitrifying biofilm formation. In this study, novel clinoptilolite composite carriers with favorable hydrophilicity, positive charge and nitrification-enhancing capability were made and implemented in IFFAS system. In comparison with conventional carriers, the novel clinoptilolite composite carriers displayed positive charges on the surface (11.7±1.1 mV, pH 7.0) with increased hydrophilicity (surface contact angle dropped to 76.7°). The novel-carriers-based reactors achieved significantly better NH4+-N removal efficiency at different influent concentrations, dissolved oxygen (DO) levels and shock loads (NH4+-N removal efficiency rose up to 20% comparing with the control reactors filled with polyethylene (PE) carriers or activated sludge). High-throughput sequencing (HTS) results indicated the novel clinoptilolite composite carriers provided favorable niche for more types of bacteria, especially for Nitrosomonadales and Nitrospirales (the functional nitrifiers in the system). The population of Nitrospirales increased by 4.51% by using novel clinoptilolite composite carriers comparing with using PE carriers, which ensured enhanced nitrification process. This study was expected to provide a practical option for enhancing wastewater nitrification performance with the novel clinoptilolite composite carrier.

关键词： Biofilm carrier     Clinoptilolite     Integrated floating fixed-film activated sludge (IFFAS)     Microbial community     Nitrification     Wastewater    

HTML PDF 收藏

Performance and kinetics of iron-based oxygen carriers reduced by carbon monoxide for chemical looping

Xiuning HUA,Wei WANG,Feng WANG

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 1130-1138 doi: 10.1007/s11783-015-0821-y

摘要： Chemical looping combustion is a promising technology for energy conversion due to its low-carbon, high-efficiency, and environmental-friendly feature. A vital issue for CLC process is the development of oxygen carrier, since it must have sufficient reactivity. The mechanism and kinetics of CO reduction on iron-based oxygen carriers namely pure Fe O and Fe O supported by alumina (Fe O /Al O ) were investigated using thermo-gravimetric analysis. Fe O /Al O showed better reactivity over bare Fe O toward CO reduction. This was well supported by the observed higher rate constant for Fe O /Al O over pure Fe O with respective activation energy of 41.1±2.0 and 33.3±0.8 kJ·mol . The proposed models were compared via statistical approach comprising Akaike information criterion with correction coupled with F-test. The phase-boundary reaction and diffusion control models approximated to 95% confidence level along with scanning electron microscopy results; revealed the promising reduction reactions of pure Fe O and Fe O /Al O . The boosting recital of iron-based oxygen carrier support toward efficient chemical looping combustion could be explained accurately through the present study.

关键词： chemical looping combustion     iron-based oxygen carriers     reduction kinetics     carbon monoxide     statistics    

HTML PDF 收藏

Laboratory experiment on using non-floating body to generate electrical energy from water waves

Arunachalam AMARKARTHIK, Srinivasan CHANDRASEKARAN, Karuppan SIVAKUMAR, Harender SINHMAR

《能源前沿（英文）》 2012年 第6卷 第4期   页码 361-365 doi: 10.1007/s11708-012-0210-1

摘要： This paper describes an innovative method of using a non-buoyant body to harness ocean waves. All the point absorbers are buoyant in nature and move up due to buoyancy and come down because of gravity. The point absorbers are designed to move along the waves to make the device efficient. These devices face excessive stress during the rough weather on account of the extreme motion of waves and cause the total device failure. The present study shows that using a non-buoyant body for conventional point absorber principle is much efficient and safer than any other device proposed till today. A small scale wave energy converter with non-buoyant body was designed, fabricated and tested in small scale wave maker. An electrical generator was coupled with the device to generate electrical energy from harnessed waves. The generator was electrically loaded and the generated power was measured. It was found from the experiments that the proposed device showed a significant improvement in electricity generation and safety during extreme conditions. In addition to the electricity generation, the characteristics of the device were also studied by using various wave and device parameters.

关键词： ocean wave energy     point absorbers     heaving body     non-floating object     heave response ratio     electrical energy generation    

HTML PDF 收藏

Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

ZHANG Ruihua, CHEN Haichu

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 433-438 doi: 10.1007/s11465-007-0074-y

摘要： This paper develops a 30 mm × 30 mm × 50 mm spherical micro actuator driven by piezoelectric ceramic stacks (PZT), and analyzes its dynamic performances. First, the space coordinate relationship of the spherical micro actuator and a dynamic model are set up. Second, The Runge-Kutta arithmetic is used to calculate the dynamical parameters of the micro actuator; the SIMULINK module of MATLAB is used to build the dynamical simulating model and then simulate it. Third, an experimental sample of the spherical micro actuator is developed, a micromanipulator is integrated with a micro-gripper based on the sample spherical micro actuator, and the experimental research on the micro assembly is conducted between a micro shaft of 180 μm and a micro spindle sleeve of 200 μm. Finally, the characteristics of the spherical micro actuator influenced by the mass of the metal sphere of the micro actuator, driving signal frequency, friction coefficient of the contact surface between the metal sphere and the friction block of the micro driving unit are analyzed. The experimental results indicate that the rotation resolution of the micro actuator reaches 0.000 1°, the rotation positioning precision reaches 0.000 5°, and the maximum working frequency is about 1200 Hz. The experimental results validate the back rotation vibration model of the spherical micro actuator. The micromanipulator integrated by the spherical micro actuator can meet the requirements of precise micro operation and assembly for micro electro mechanical systems (MEMS) or other microelements in micro degree fields.

关键词： spherical     micro-gripper     friction coefficient     dynamic     frequency    

HTML PDF 收藏

Development of a redundant anthropomorphic hydraulically actuated manipulator with a roll–pitch–yaw spherical

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 698-710 doi: 10.1007/s11465-021-0646-2

摘要： The demand for redundant hydraulic manipulators that can implement complex heavy-duty tasks in unstructured areas is increasing; however, current manipulator layouts that remarkably differ from human arms make intuitive kinematic operation challenging to achieve. This study proposes a seven-degree-of-freedom (7-DOF) redundant anthropomorphic hydraulically actuated manipulator with a novel roll–pitch–yaw spherical wrist. A hybrid series–parallel mechanism is presented to achieve the spherical wrist design, which consists of two parallel linear hydraulic cylinders to drive the yaw/pitch 2-DOF wrist plate connected serially to the roll structure. Designed as a 1R PRRR-1S PU mechanism (“R”, “P”, “S”, and “U” denote revolute, prismatic, spherical, and universal joints, respectively; the underlined letter indicates the active joint), the 2-DOF parallel structure is partially decoupled to obtain simple forward/inverse kinematic solutions in which a closed-loop subchain “R PRR” is included. The 7-DOF manipulator is then designed, and its third joint axis goes through the spherical center to obtain closed-form inverse kinematic computation. The analytical inverse kinematic solution is drawn by constructing self-motion manifolds. Finally, a physical prototype is developed, and the kinematic analysis is validated via numerical simulation and test results.

关键词： hydraulic manipulator     inverse kinematic     redundant design     spherical wrist    

HTML PDF 收藏

Synthesis and electrocatalytic property of cubic and spherical nanoparticles of cobalt platinum alloys

Xiaowei TENG, Hong YANG,

《化学科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 45-51 doi: 10.1007/s11705-009-0308-0

摘要： This paper describes the morphological control and electrocatalytic property of CoPt nanoparticles. Both cubic and spherical CoPt nanoparticles were made using cobalt carbonyl and platinum 2,4-pentanedionate under different reaction temperatures in the presence of capping reagents, which included adamantanecarboxylic acid and hexadecylamine. Effects of heterogeneous species on shape of the CoPt nanoparticles were examined by replacing cobalt carbonyl with silver acetylacetonate. Our results suggest that the formation of different shapes of CoPt particles could be attributed to the affinity between cobalt and platinum, and the effects of capping agents. The size and shape dependent electrocatalytic properties of these nanoparticles were examined based on the direct methanol oxidation reaction.

关键词： spherical     2     4-pentanedionate     adamantanecarboxylic     acetylacetonate     electrocatalytic    

HTML PDF 收藏

On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 34-40 doi: 10.1007/s11465-014-0290-1

摘要：

As the instant centers in planar mechanisms, the instantaneous poles (or instant poles, in brief) can be used for kinematic analysis in spherical mechanisms. One of the mandatory steps in this analysis is the determination of the location of these poles. This paper presents a theorem showing analytically that the locus of an unknown secondary instant pole in two-degree-of-freedom (2-DOF) spherical mechanisms is a great circle (GC). The exact location of the pole on its GC is obtained based on the configuration of the mechanism and velocity ratio of the two inputs. Moreover, using the results of the theorem, a geometrical technique is presented to determine the GC of the pole.

关键词： spherical mechanisms     instantaneous poles     great circle     angular velocity    

HTML PDF 收藏

Dynamic performance of submerged floating tunnel with different mooring styles subjected to anchor cable

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0932-7

摘要： Submerged floating tunnels (SFTs) are novel structures for transportation across long- and deep-strait regions. Owing to severe wave and current excitation as well as the effects of underwater structures and corrosion, the risk of local anchor cable failure is high, which can result in the progressive failure of the entire structure. In this study, experimental and numerical investigations are conducted to analyze the dynamic behavior of an SFT with different mooring styles under local cable failure. A custom-designed cable failure device and the birth-and-death element method are used to simulate cable failure (i.e., progressive failure) via experiments and numerical simulation, respectively. A physical-scale segmental model of an SFT with different mooring styles under anchor cable failure is developed in this study. A segmental and entire-length mathematical model is developed using the ANSYS program to perform the numerical simulation. The results of the segmental numerical and experimental models indicate good agreement. The dynamic response of an SFT with different mooring styles under cable failure is comprehensively investigated by investigating the effects of key parameters (wave period, buoyant weight ratio, and cable failure mechanism). Moreover, the progressive failure of the SFT under cable failure is investigated via a segment model test and a numerical simulation of its entire length. The present study can serve as a reference for the safer designs of the SFT mooring style.

关键词： dynamic behaviors     submerged floating tunnel     cable failure     mooring style     progressive failure    

HTML PDF 收藏

Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

《机械工程前沿（英文）》 2009年 第4卷 第4期   页码 379-385 doi: 10.1007/s11465-009-0075-0

摘要： Singularity analysis plays an important role in the design of robots, especially for parallel robots. In this paper, the direct and inverse kinematics of an orthogonal spherical two-degree-of-freedom parallel mechanism is proposed based on the modified Euler angles. All the singular poses of the mechanism are achieved through the direct kinematic analysis. Self-motions, which are different from the general spherical 5 parallel mechanisms, are also discussed. Singularity loci in the joint space and Cartesian space are plotted according to the Jacobin of the mechanism. Result shows that the singularity loci at the joint space are two circles and one line, whereas at the Cartesian space are a circle.

关键词： 2-DOF orthogonal spherical parallel mechanism     singularity loci     self-motions    

HTML PDF 收藏

Numerical simulation of multi-body floating piers to investigate pontoon stability

Mostafa Shahrabi, Khosrow Bargi

《结构与土木工程前沿（英文）》 2013年 第7卷 第3期   页码 325-331 doi: 10.1007/s11709-013-0209-7

摘要： The objective of this study is to develop a procedure to analyze the motions of a floating pier comprised of several pontoons that are modeled as rigid bodies and connected to each other by flexible and rigid connectors. Recently, the use offloating piers has increased because of their advantages, such as faster and higher-quality construction, seismic force isolation for a full-scale mooring system, low dependence on local soil conditions and tides, ability to relocate or reconfigure the pier modules during the operation period and 75-100 years of repair-free service. A floating pier consists of a pier, access bridge, mooring system and fender system, each of which comes in many variations to suit different usages and construction considerations. The typical loads used in the design of these piers are dead loads, live loads, mooring loads, fender loads and environmental loads induced by wind, currents and waves. For numerical simulation, three types of piers are used: passenger piers, light-cargo piers and semi-heavy-cargo piers. The selected piers consist of several large pontoons joined by pivots and have a pile-based mooring system. These piers are modeled by SAP2000software as two-dimensional frames that are linked together. As the first step, each type of pier is subjected to loading, and its general behavior is assessed. According to this behavior, the major load combinations are described for the design of piers and analyzed to determine the behavior of the modules. Lastly, according to the analysis results and the safe use and stability considerations, such as the maximum draft and longitudinal gradient, the dimensions of each module in each pier type are presented.

关键词： coastal structures     numerical simulation     floating pier     rigid pontoons     stability    

HTML PDF 收藏

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 344-353 doi: 10.1007/s11465-014-0320-z

摘要：

This paper is a detailed exploration of instantaneous poles for a class of two-degree-of-freedom (two-DOF) spherical mechanisms (SMs) with seven links or bars. For two-DOF SMs, the secondary instantaneous poles (the ones which cannot be found by direct inspection) must lie on the specified great circles. For many of these mechanisms, however, some of these great circles cannot be obtained by a direct application of Aronhold-Kennedy theorem. This paper presents geometrical and analytical techniques to locate these unknown great circles for three topologies of seven-bar two-DOF SMs.

关键词： spherical mechanisms     instantaneous poles     Aronhold-Kennedy theorem     great circles     pencil of meridian    

HTML PDF 收藏

A method for predicting consolidation settlements of floating column improved clayey subsoil

Jinchun CHAI, Supasit PONGSIVASATHIT,

《结构与土木工程前沿（英文）》 2010年 第4卷 第2期   页码 241-251 doi: 10.1007/s11709-010-0024-3

摘要： A method of predicting the consolidation settlement-time curve of floating soil-cement column on improved soft clayey subsoil has been proposed. The degree of the consolidation (()) of the system is calculated by the double soil-layer consolidation theory, and the methods for evaluating the equivalent hydraulic conductivity () and the coefficient of volume compressibility () of the part of the column improved layer have been proposed. The effectiveness of the method was verified by comparing predictions with the results of finite element analysis (FEA) using a unit cell model. The consolidation settlement (()) can be calculated by the method of treating a part of the column improved layer as an unimproved layer and using the corresponding average () value. By comparing the predicted results with the measurements of laboratory model tests and three case histories in Fukuoka, Japan, the effectiveness of the proposed methods has been verified. It is suggested that the method can be used for designing the soft clayey subsoil improvement using floating soil-cement columns.

关键词： cement depth mixing     ground improvement     consolidation     settlement    

HTML PDF 收藏

Shape optimization of aluminium alloy spherical reticulated shells considering nonlinearities

Wei LIU; Lishu XU; Shaojun ZHU; Lijuan LI; Feng LIU; Zhe XIONG

《结构与土木工程前沿（英文）》 2022年 第16卷 第12期   页码 1565-1580 doi: 10.1007/s11709-022-0867-4

摘要： This study proposes a shape optimization method for K6 aluminum alloy spherical reticulated shells with gusset joints, considering geometric, material, and joint stiffness nonlinearities. The optimization procedure adopts a genetic algorithm in which the elastoplastic non-linear buckling load is selected as the objective function to be maximized. By confinement of the adjustment range of the controlling points, optimization results have enabled a path toward achieving a larger elastoplastic non-linear buckling load without changing the macroscopic shape of the structure. A numerical example is provided to demonstrate the effectiveness of the proposed method. In addition, the variation in structural performance during optimization is illustrated. Through parametric analysis, practical design tables containing the parameters of the optimized shape are obtained for aluminum alloy spherical shells with common geometric parameters. To explore the effect of material nonlinearity, the optimal shapes obtained based on considering and not considering material non-linear objective functions, the elastoplastic and elastic non-linear buckling loads, are compared.

关键词： shape optimization     aluminum alloy     spherical reticulated shell     non-linear buckling     material nonlinearity     genetic algorithm    

HTML PDF 收藏

Atomic force microscopy study on the microtopography of natural organic matter and newly formed hydrous MnO2

GUO Jin, MA Jun, SHI Xuehua

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 251-256 doi: 10.1007/s11783-007-0043-z

摘要： To understand the water purification mechanism of potassium permanganate as a coagulation-aid during the preoxidation process, the microtopography of its reductive products, the newly formed hydrous manganese dioxide and the aged hydrous manganese dioxide, was investigated. The morphology of natural organic matter (NOM) adsorbed by the newly formed hydrous manganese dioxide was also compared with that of NOM alone. By using the tapping mode atomic force microscopy (AFM), the observation results show that the newly formed hydrous manganese dioxide possess a perforated sheet (with a thickness of 0 1.75 nm) as well as some spherical particle structures compared with the hydrous manganese dioxide with 2 h aging time, which demonstrated that the newly formed hydrous manganese dioxide had a large surface area and adsorption capacity. When 1 mmol/L newly formed hydrous manganese dioxide was added, the microtopography of NOM molecules shifted from a loosely dispersed pancake shape (with adsorption height of 5 8.5 nm) to a densely dispersed and uniform spherical structure. These results provide a valid proof that it is the perfect adsorption capability of the newly formed hydrous manganese dioxide that might result in the coagulation aid effect of potassium permanganate preoxidation.

关键词： spherical     microtopography     potassium permanganate     uniform spherical     morphology    

HTML PDF 收藏

标题 作者 时间 类型 操作

reduction in sequencing batch biofilm reactor: Performances, mechanisms and comparison of different carriers

Yonglei Wang, Baozhen Liu, Kefeng Zhang, Yongjian Liu, Xuexin Xu, Junqi Jia

期刊论文

Enhanced nitrification in integrated floating fixed-film activated sludge (IFFAS) system using novelclinoptilolite composite carrier

Aoshuang Jing, Tao Liu, Xie Quan, Shuo Chen, Yaobin Zhang

期刊论文

Performance and kinetics of iron-based oxygen carriers reduced by carbon monoxide for chemical looping

Xiuning HUA,Wei WANG,Feng WANG

期刊论文

Laboratory experiment on using non-floating body to generate electrical energy from water waves

Arunachalam AMARKARTHIK, Srinivasan CHANDRASEKARAN, Karuppan SIVAKUMAR, Harender SINHMAR

期刊论文

Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

ZHANG Ruihua, CHEN Haichu

期刊论文

Development of a redundant anthropomorphic hydraulically actuated manipulator with a roll–pitch–yaw spherical

期刊论文

Synthesis and electrocatalytic property of cubic and spherical nanoparticles of cobalt platinum alloys

Xiaowei TENG, Hong YANG,

期刊论文

On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

Dynamic performance of submerged floating tunnel with different mooring styles subjected to anchor cable

期刊论文

Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

期刊论文

Numerical simulation of multi-body floating piers to investigate pontoon stability

Mostafa Shahrabi, Khosrow Bargi

期刊论文

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

A method for predicting consolidation settlements of floating column improved clayey subsoil

Jinchun CHAI, Supasit PONGSIVASATHIT,

期刊论文

Shape optimization of aluminium alloy spherical reticulated shells considering nonlinearities

Wei LIU; Lishu XU; Shaojun ZHU; Lijuan LI; Feng LIU; Zhe XIONG

期刊论文

Atomic force microscopy study on the microtopography of natural organic matter and newly formed hydrous MnO2

GUO Jin, MA Jun, SHI Xuehua

期刊论文