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期刊论文 1391

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Adsorption performance and physicochemical mechanism of MnO

Xiaoyan Deng, Luxing Wang, Qihui Xiu, Ying Wang, Hong Han, Dongmei Dai, Yongji Xu, Hongtao Gao, Xien Liu

《化学科学与工程前沿(英文)》 2021年 第15卷 第3期   页码 538-551 doi: 10.1007/s11705-020-1958-1

摘要: In this work, an adsorbent, which we call MnPT, was prepared by combining MnO , polyethylenimine and tannic acid, and exhibited efficient performance for Cu(II) and Cr(VI) removal from aqueous solution. The oxygen/nitrogen-containing functional groups on the surface of MnPT might increase the enrichment of metal ions by complexation. The maximum adsorption capacities of MnPT for Cu(II) and Cr(VI) were 121.5 and 790.2 mg·g , respectively. The surface complexation formation model was used to elucidate the physicochemical interplay in the process of Cu(II) and Cr(VI) co-adsorption on MnPT. Electrostatic force, solvation action, adsorbate–adsorbate lateral interaction, and complexation were involved in the spontaneous adsorption process. Physical electrostatic action was dominant in the initial stage, whereas chemical action was the driving force leading to adsorption equilibrium. It should be noted that after adsorption on the surface of MnPT, Cr(VI) reacted with some reducing functional groups (hydroxylamine-NH ) and was converted into Cr(III). The adsorption capacity declined by 12% after recycling five times. Understanding the adsorption mechanism might provide a technical basis for the procedural design of heavy metal adsorbents. This MnPT nanocomposite has been proven to be a low-cost, efficient, and promising adsorbent for removing heavy metal ions from wastewater.

关键词: MnO2-polyethylenimine-tannic acid composite     surface complexation formation model     Cu(II)     Cr(VI)     physicochemical mechanism    

Formation mechanism and modeling of surface waviness in incremental sheet forming

《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0679-1

摘要: Improving and controlling surface quality has always been a challenge for incremental sheet forming (ISF), whereas the generation mechanism of waviness surface is still unknown, which impedes the widely application of ISF in the industrial field. In this paper, the formation mechanism and the prediction of waviness are both investigated through experiments, numerical simulation, and theoretical analysis. Based on a verified finite element model, the waviness topography is predicted numerically for the first time, and its generation is attributed to the residual bending deformation through deformation history analysis. For more efficient engineering application, a theoretical model for waviness height is proposed based on the generation mechanism, using a modified strain function considering deformation modes. This work is favorable for the perfection of formation mechanism and control of surface quality in ISF.

关键词: surface waviness     incremental sheet forming     numerical simulation     formation mechanism     deformation history    

Materials and surface engineering to control bacterial adhesion and biofilm formation: A review of recent

Huan GU, Dacheng REN

《化学科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 20-33 doi: 10.1007/s11705-014-1412-3

摘要: Bacterial adhesion to surfaces and subsequent biofilm formation are a leading cause of chronic infections and biofouling. These processes are highly sensitive to environmental factors and present a challenge to research using traditional approaches with uncontrolled surfaces. Recent advances in materials research and surface engineering have brought exciting opportunities to pattern bacterial cell clusters and to obtain synthetic biofilms with well-controlled cell density and morphology of cell clusters. In this article, we will review the recent achievements in this field and comment on the future directions.

关键词: surface engineering     materials     bacterial adhesion     biofilm     control     review    

Strategies on designing multifunctional surfaces to prevent biofilm formation? ?

Yang Lu,Zhanguo Yue,Wei Wang,Zhiqiang Cao

《化学科学与工程前沿(英文)》 2015年 第9卷 第3期   页码 324-335 doi: 10.1007/s11705-015-1529-z

摘要: Bacteria adhesion and biofilm formation have raised severe problems on public health, food industry and many other areas. A variety of reagents and surface coatings have been developed to kill bacteria and/or limit their interaction with surfaces. It has also attracted many efforts to integrate different bactericidal elements together and maximize antibacterial efficiency. Herein, we review mechanisms for both passive and active approaches to resist and kill bacteria respectively, and discuss integrated strategies based on these two approaches. We also offer perspective on future research direction.

关键词: antimicrobial     surface     multifunctional    

Experimental studies on extraction of cobalt ions from dilute aqueous solutions by using complexation-ultrafiltration

Jianxian ZENG, Junfeng LIU, Niandong HUANG,

《化学科学与工程前沿(英文)》 2010年 第4卷 第3期   页码 360-366 doi: 10.1007/s11705-009-0269-3

摘要: The extraction of cobalt ions from dilute aqueous solutions was investigated by ultrafiltration with the help of poly(acrylic acid) sodium salt (PAASS). Polysulfone and polyethersulfone hollow fiber ultrafiltration membranes were employed in this process. The kinetics of complexation reaction was studied for PAASS with Co. Results showed that, under a large excess of PAASS, it takes 65, 55 and 40 min at pH 5, 6 and 7, respectively, to get the equilibrium of complexation. The reaction kinetics can be described by a pseudo-first-order equation. Then, the effects of various parameters on the extraction of Co were examined in detail. Results indicated that loading ratio, pH value and low-molecular competitive complexing agent affect significantly cobalt rejection coefficient . Furthermore, a concentration experiment was carried out at pH 7. With increasing volume concentration factor, membrane flux declines slowly, and value is always about 1. The concentrated retentate was used further for a decomplexation experiment. The decomplexation ratio of cobalt-PAASS complex reaches as high as 90.1%. After the decomplexation step, a diafiltration experiment was performed at pH 2.5. Cobalt ions can be extracted satisfactorily from the retentate, and a purified PAASS is obtained.

Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD

《环境科学与工程前沿(英文)》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1494-3

摘要:

• A Passive Aeration Ditch was developed to treat decentralized wastewater.

关键词: Decentralized wastewater     Passive aeration ditch     Biofilm formation     C/N ratio     Salinity     Model simulation    

The formation mechanism and the influence factor of residual stress in machining

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 265-269 doi: 10.1007/s11465-014-0311-0

摘要:

Residual stresses generated in cutting process have important influences on workpiece performance. The paper presents a method of theoretical analysis in order to explicate the formation mechanism of residual stresses in cutting. An important conclusion is drawn that the accumulated plastic strain is the main factor which determines the nature and the magnitude of surface residual stresses in the workpiece. On the basis of the analytical model for residual stress, a series of simulations for residual stress prediction during cutting AISI 1045 steel are implemented in order to obtain the influences of cutting speed, depth of cut and tool edge radius on surface residual stress in the workpiece. And these influences are explained from the perspective of formation mechanism of residual stress in cutting. The conclusions have good applicability and can be used to guide the parameters selection in actual production.

关键词: residual stress     analytical model     strain     plastic     cutting parameter    

Dynamic visco-plastic memorial nested yield surface model of soil

ZHUANG Haiyang, CHEN Guoxing, ZHU Dinghua

《结构与土木工程前沿(英文)》 2008年 第2卷 第1期   页码 49-55 doi: 10.1007/s11709-008-0003-0

摘要: Under cyclic loadings, the plastic strain of soft soil will take place under very small shear strain. So the visco-plastic model is appropriate to be used to model the dynamic characteristics of soft soil. Based on the principles of geotechnical plastic mechanics, the incremental visco-plastic memorial nested yield surface model is developed by using the field theory of nonlinear isotropic materials and the theory of kinematical hardening modulus. At the end of anyone time increment, the inverted loading surface, the damaged surface and the initial loading surface which is tangent with the inside of inverted loading surface are memorized respectively. The kinematical behavior of yield surface is defined by using these three surfaces. The developed model in this paper is successfully implemented in ABAQUS using FORTRAN subroutine. The predicted stress-strain relationships of soft soil are compared with the test results given by dynamic triaxial tests. It is proved that the cyclic undrained stress-strain relation of soils can be fairly simulated by the model. At last, the nonlinear earthquake response of a representative soft site in Nanjing city is calculated with the dynamic behavior of soils modeled by the new developed model. The results are accordant to the earthquake response of soft site given by other scholars.

关键词: developed     dynamic     surface     inverted     appropriate    

Modeling and verifying chlorine decay and chloroacetic acid formation in drinking water chlorination

Wenjun LIU, Shaoying QI,

《环境科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 65-72 doi: 10.1007/s11783-010-0010-y

摘要: This study presents a phenomenological model that can be used by the water professionals to quantify chlorine decay and disinfection byproduct (DBP) formation in water. The kinetic model was developed by introducing the concept of limiting chlorine demand and extending an established reactive species approach. The limiting chlorine demand, which quantifies chlorine reactive natural organic matter (NOM) on an equivalent basis, was mathematically defined by the relation between ultimate chlorine residue and initial chlorine dose. It was found experimentally that NOM in water has limiting chlorine demand that increases with chlorine dose once the ultimate residue is established. These results indicated that the complex NOM has a unique ability to adjust chemically to the change in redox condition caused by the free chlorine. It is attributed mainly to the redundant functional groups that persist in heterogeneous NOM molecules. The results also demonstrated that the effect of chlorine dose on the rate of chlorine decay can be quantitatively interpreted with the limiting chlorine demand. The kinetic model developed was validated for chlorine decay and chloroacetic acid formation in finished drinking water.

关键词: chlorine demand     chlorine decay     chloroacetic acids     disinfection byproducts     model    

Predictive model to decouple the contributions of friction and plastic deformation to machined surface

Subhash ANURAG, Yuebin GUO,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 247-255 doi: 10.1007/s11465-010-0097-7

摘要: Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However, the temperature of a machined surface is challenging for in-situ measurement. Furthermore, the individual contribution of tool/work friction and plastic deformation of work materials to surface temperature is very difficult to quantify because the measured temperature is always the resultant temperature. This lack of understanding on the temperature distribution blocks the design of effective cutting tool geometries and materials to minimize surface temperature. This study provides a finite element method based on a predictive model to decouple the contributions of tool/work friction and material plastic deformation to surface temperature in a dry cutting process. The study shows that the plastic deformation of work material contributes to the majority of surface temperature, whereas the tool/work friction contribution is secondary. High temperatures are produced when more materials are plowed under the cutting edge. A large tool/work friction leads to higher surface temperatures, and the use of a cutting tool with physical properties in process simulation significantly improves the accuracy of predicted surface temperatures. Residual stress reversal from subsurface maximum residual to surface maximum residual stress may occur when tool/work friction increases.

关键词: surface temperature     friction     residual stress     finite element analysis (FEA)     dry cutting     tool property    

New response surface model and its applications in aerodynamic optimization of axial compressor blade

LIU Xiaojia, NING Fangfei

《能源前沿(英文)》 2008年 第2卷 第4期   页码 541-549 doi: 10.1007/s11708-008-0077-3

摘要: A parametric method for the axial compressor 2D blade profiles is proposed in which the blade geometries are defined with the parameters commonly used for blade definition, which ensures that the geometric significance is clear and an unreasonable blade profile is not generated. Several illustrations are presented to show the fitting precision of the method. A novel response surface model is proposed which regards the objective distribution function in the vicinity of a sample as normal school, and then generates the response surface function in the whole design space by a linear combination of distribution functions of all the samples. Based on this model, a numerical aerodynamic optimization platform for the axial compressor 2D blade profiles is developed, by which aerodynamic optimization of two compressor blade profiles are presented.

关键词: definition     objective distribution     fitting precision     combination     numerical aerodynamic    

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要: A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词: cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

Enhancement of the polynomial functions response surface model for real-time analyzing ozone sensitivity

Jiangbo Jin, Yun Zhu, Jicheng Jang, Shuxiao Wang, Jia Xing, Pen-Chi Chiang, Shaojia Fan, Shicheng Long

《环境科学与工程前沿(英文)》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1323-0

摘要: Abstract • The calculation process and algorithm of response surface model (RSM) were enhanced. • The prediction errors of RSM in the margin and transition areas were greatly reduced. • The enhanced RSM was able to analyze O3-NOx-VOC sensitivity in real-time. • The O3 formations were mainly sensitive to VOC, for the two case study regions. Quantification of the nonlinearities between ambient ozone (O3) and the emissions of nitrogen oxides (NOx) and volatile organic compound (VOC) is a prerequisite for an effective O3 control strategy. An Enhanced polynomial functions Response Surface Model (Epf-RSM) with the capability to analyze O3-NOx-VOC sensitivities in real time was developed by integrating the hill-climbing adaptive method into the optimized Extended Response Surface Model (ERSM) system. The Epf-RSM could single out the best suited polynomial function for each grid cell to quantify the responses of O3 concentrations to precursor emission changes. Several comparisons between Epf-RSM and pf-ERSM (polynomial functions based ERSM) were performed using out-of-sample validation, together with comparisons of the spatial distribution and the Empirical Kinetic Modeling Approach diagrams. The comparison results showed that Epf-RSM effectively addressed the drawbacks of pf-ERSM with respect to over-fitting in the margin areas and high biases in the transition areas. The O3 concentrations predicted by Epf-RSM agreed well with Community Multi-scale Air Quality simulation results. The case study results in the Pearl River Delta and the north-western area of the Shandong province indicated that the O3 formations in the central areas of both the regions were more sensitive to anthropogenic VOC in January, April, and October, while more NOx-sensitive in July.

关键词: Response surface model     Hill-climbing algorithm     Ozone pollution     Precursor emissions     Control strategy    

Fiber-reinforced composites in milling and grinding: machining bottlenecks and advanced strategies

《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0680-8

摘要: Fiber-reinforced composites have become the preferred material in the fields of aviation and aerospace because of their high-strength performance in unit weight. The composite components are manufactured by near net-shape and only require finishing operations to achieve final dimensional and assembly tolerances. Milling and grinding arise as the preferred choices because of their precision processing. Nevertheless, given their laminated, anisotropic, and heterogeneous nature, these materials are considered difficult-to-machine. As undesirable results and challenging breakthroughs, the surface damage and integrity of these materials is a research hotspot with important engineering significance. This review summarizes an up-to-date progress of the damage formation mechanisms and suppression strategies in milling and grinding for the fiber-reinforced composites reported in the literature. First, the formation mechanisms of milling damage, including delamination, burr, and tear, are analyzed. Second, the grinding mechanisms, covering material removal mechanism, thermal mechanical behavior, surface integrity, and damage, are discussed. Third, suppression strategies are reviewed systematically from the aspects of advanced cutting tools and technologies, including ultrasonic vibration-assisted machining, cryogenic cooling, minimum quantity lubrication (MQL), and tool optimization design. Ultrasonic vibration shows the greatest advantage of restraining machining force, which can be reduced by approximately 60% compared with conventional machining. Cryogenic cooling is the most effective method to reduce temperature with a maximum reduction of approximately 60%. MQL shows its advantages in terms of reducing friction coefficient, force, temperature, and tool wear. Finally, research gaps and future exploration directions are prospected, giving researchers opportunity to deepen specific aspects and explore new area for achieving high precision surface machining of fiber-reinforced composites.

关键词: milling     grinding     fiber-reinforced composites     damage formation mechanism     delamination     material removal mechanism     surface integrity     minimum quantity lubrication    

Accounting for local features of fouling formation on PHE heat transfer surface

Petro Kapustenko, Jiří J. Klemeš, Olga Arsenyeva, Olexandr Matsegora, Oleksandr Vasilenko

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 619-629 doi: 10.1007/s11705-018-1736-5

摘要: The fouling phenomena can create significant operational problems in the industry by deteriorating heat recuperation, especially in heat exchangers with enhanced heat transfer. For a correct prediction of fouling development, the reliable fouling models must be used. The analysis of existing fouling models is presented. The chemical reaction and transport model developed earlier for a description of fouling on intensified heat transfer surfaces is used for modeling of plate heat exchanger (PHE) subjected to fouling. The mathematical model consists of a system of differential and algebraic equations. The integration of it is performed by finite difference method with developed software for personal computer. For countercurrent streams arrangement in PHE the solution of two-point boundary problem is realized on every time step. It enables to estimate local parameters of heat transfer process with fouling formation and its development in time with the growth of deposited fouling layer. Two examples of model application in cases of PHEs working at sugar factory and in district heating network are presented. The comparison with experimental data confirmed the model validity and the possibility of its application to determine the performance of PHE subjected to fouling.

关键词: heat transfer     fouling     plate heat exchanger     mathematical model    

标题 作者 时间 类型 操作

Adsorption performance and physicochemical mechanism of MnO

Xiaoyan Deng, Luxing Wang, Qihui Xiu, Ying Wang, Hong Han, Dongmei Dai, Yongji Xu, Hongtao Gao, Xien Liu

期刊论文

Formation mechanism and modeling of surface waviness in incremental sheet forming

期刊论文

Materials and surface engineering to control bacterial adhesion and biofilm formation: A review of recent

Huan GU, Dacheng REN

期刊论文

Strategies on designing multifunctional surfaces to prevent biofilm formation? ?

Yang Lu,Zhanguo Yue,Wei Wang,Zhiqiang Cao

期刊论文

Experimental studies on extraction of cobalt ions from dilute aqueous solutions by using complexation-ultrafiltration

Jianxian ZENG, Junfeng LIU, Niandong HUANG,

期刊论文

Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD

期刊论文

The formation mechanism and the influence factor of residual stress in machining

null

期刊论文

Dynamic visco-plastic memorial nested yield surface model of soil

ZHUANG Haiyang, CHEN Guoxing, ZHU Dinghua

期刊论文

Modeling and verifying chlorine decay and chloroacetic acid formation in drinking water chlorination

Wenjun LIU, Shaoying QI,

期刊论文

Predictive model to decouple the contributions of friction and plastic deformation to machined surface

Subhash ANURAG, Yuebin GUO,

期刊论文

New response surface model and its applications in aerodynamic optimization of axial compressor blade

LIU Xiaojia, NING Fangfei

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Enhancement of the polynomial functions response surface model for real-time analyzing ozone sensitivity

Jiangbo Jin, Yun Zhu, Jicheng Jang, Shuxiao Wang, Jia Xing, Pen-Chi Chiang, Shaojia Fan, Shicheng Long

期刊论文

Fiber-reinforced composites in milling and grinding: machining bottlenecks and advanced strategies

期刊论文

Accounting for local features of fouling formation on PHE heat transfer surface

Petro Kapustenko, Jiří J. Klemeš, Olga Arsenyeva, Olexandr Matsegora, Oleksandr Vasilenko

期刊论文