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Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare

《环境科学与工程前沿(英文)》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1513-4

摘要:

• Season and landform influenced spatiotemporal patterns of abundant and rare taxa.

关键词: Rare taxa     Biogeography     Community assembly     Bacterioplankton     The Yangtze River    

Impacts of backwashing on micropollutant removal and associated microbial assembly processes in sand

《环境科学与工程前沿(英文)》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1634-z

摘要:

● Backwashing in sand filters with 2-h and 4-h EBCTs was simulated.

关键词: Sand filter     Backwashing     Recovery     Micropollutants     Community composition    

Meter-scale variation within a single transect demands attention to taxon accumulation curves in riverine microbiome studies

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1543-6

摘要:

● Riverine microbiomes exhibited hyperlocal variation within a single transect.

关键词: Microbiome     Freshwater     Taxon accumulation curve     Community assembly    

Assembly of biosynthetic pathways in

Lidan Ye,Xiaomei Lv,Hongwei Yu

《化学科学与工程前沿(英文)》 2017年 第11卷 第1期   页码 126-132 doi: 10.1007/s11705-016-1597-8

摘要: A robust and versatile tool for multigene pathway assembly is a key to the biosynthesis of high-value chemicals. Here we report the rapid construction of biosynthetic pathways in using a marker recyclable integrative toolbox (pUMRI) developed in our research group, which has features of ready-to-use, convenient marker recycling, arbitrary element replacement, shuttle plasmid, auxotrophic marker independence, GAL regulation, and decentralized assembly. Functional isoprenoid biosynthesis pathways containing 4–11 genes with lengths ranging from ~10 to ~22 kb were assembled using this toolbox within 1–5 rounds of reiterative recombination. In combination with GAL-regulated metabolic engineering, high production of isoprenoids (e.g., 16.3 mg?g dcw carotenoids) was achieved. These results demonstrate the wide range of application and the efficiency of the pUMRI toolbox in multigene pathway construction of .

关键词: pathway assembly     toolbox     reiterative recombination     S. cerevisiae     biosynthesis    

A novel task-oriented framework for dual-arm robotic assembly task

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 528-545 doi: 10.1007/s11465-021-0638-2

摘要: In industrial manufacturing, the deployment of dual-arm robots in assembly tasks has become a trend. However, making the dual-arm robots more intelligent in such applications is still an open, challenging issue. This paper proposes a novel framework that combines task-oriented motion planning with visual perception to facilitate robot deployment from perception to execution and finish assembly problems by using dual-arm robots. In this framework, visual perception is first employed to track the effects of the robot behaviors and observe states of the workpieces, where the performance of tasks can be abstracted as a high-level state for intelligent reasoning. The assembly task and manipulation sequences can be obtained by analyzing and reasoning the state transition trajectory of the environment as well as the workpieces. Next, the corresponding assembly manipulation can be generated and parameterized according to the differences between adjacent states by combining with the prebuilt knowledge of the scenarios. Experiments are set up with a dual-arm robotic system (ABB YuMi and an RGB-D camera) to validate the proposed framework. Experimental results demonstrate the effectiveness of the proposed framework and the promising value of its practical application.

关键词: dual-arm assembly     AI reasoning     intelligent system     task-oriented motion planning     visual perception    

Pareto lexicographic α-robust approach and its application in robust multi objective assembly line balancing

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 257-264 doi: 10.1007/s11465-014-0294-x

摘要:

Robustness in most of the literature is associated with min-max or min-max regret criteria. However, these criteria of robustness are conservative and therefore recently new criteria called, lexicographic α-robust method has been introduced in literature which defines the robust solution as a set of solutions whose quality or jth largest cost is not worse than the best possible jth largest cost in all scenarios. These criteria might be significant for robust optimization of single objective optimization problems. However, in real optimization problems, two or more than two conflicting objectives are desired to optimize concurrently and solution of multi objective optimization problems exists in the form of a set of solutions called Pareto solutions and from these solutions it might be difficult to decide which Pareto solution can satisfy min-max, min-max regret or lexicographic α-robust criteria by considering multiple objectives simultaneously. Therefore, lexicographic α-robust method which is a recently introduced method in literature is extended in the current research for Pareto solutions. The proposed method called Pareto lexicographic α-robust approach can define Pareto lexicographic α-robust solutions from different scenarios by considering multiple objectives simultaneously. A simple example and an application of the proposed method on a simple problem of multi objective optimization of simple assembly line balancing problem with task time uncertainty is presented to get their robust solutions. The presented method can be significant to implement on different multi objective robust optimization problems containing uncertainty.

关键词: Pareto     lexicographic α-robust     assembly line balancing    

Assembly design system based on engineering connection

Wensheng YIN

《机械工程前沿(英文)》 2016年 第11卷 第4期   页码 423-432 doi: 10.1007/s11465-016-0382-1

摘要:

An assembly design system is an important part of computer-aided design systems, which are important tools for realizing product concept design. The traditional assembly design system does not record the connection information of production on the engineering layer; consequently, the upstream design idea cannot be fully used in the downstream design. An assembly design model based on the relationship of engineering connection is presented. In this model, all nodes are divided into two categories: The component and the connection. Moreover, the product is constructed on the basis of the connection relationship of the components. The model is an And/Or graph and has the ability to record all assembly schemes. This model records only the connection information that has engineering application value in the product design. In addition, this model can significantly reduce the number of combinations, and is very favorable for the assembly sequence planning in the downstream. The system contains a connection knowledge system that can be mapped to the connection node, and the connection knowledge obtained in practice can be returned to the knowledge system. Finally, VC++6.0 is used to develop a prototype system called Connect-based Assembly Planning (CAP). The relationship between the CAP system and the commercial assembly design system is also established.

关键词: product design     assembly design     engineering connection     assembly sequence planning    

Enzyme-instructed self-assembly of peptides containing phosphoserine to form supramolecular hydrogels

Jie Zhou, Xuewen Du, Jiaqing Wang, Natsuko Yamagata, Bing Xu

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 509-515 doi: 10.1007/s11705-017-1613-7

摘要: Enzyme-instructed self-assembly (EISA) offers a facile approach to explore the supramolecular assemblies of small molecules in cellular milieu for a variety of biomedical applications. One of the commonly used enzymes is phosphatase, but the study of the substrates of phosphatases mainly focuses on the phosphotyrosine containing peptides. In this work, we examine the EISA of phosphoserine containing small peptides for the first time by designing and synthesizing a series of precursors containing only phosphoserine or both phosphoserine and phosphotyrosine. Conjugating a phosphoserine to the -terminal of a well-established self-assembling peptide backbone, (naphthalene-2-ly)-acetyl-diphenylalanine (NapFF), affords a novel hydrogelation precursor for EISA. The incorporation of phosphotyrosine, another substrate of phosphatase, into the resulting precursor, provides one more enzymatic trigger on a single molecule, and meanwhile increases the precursors’ propensity to aggregate after being fully dephosphorylated. Exchanging the positions of phosphorylated serine and tyrosine in the peptide backbone provides insights on how the specific molecular structures influence self-assembling behaviors of small peptides and the subsequent cellular responses. Moreover, the utilization of D-amino acids largely enhances the biostability of the peptides, thus providing a unique soft material for potential biomedical applications.

关键词: enzyme-instructed self-assembly     phosphoserine     phosphatase     supramolecular hydrogel    

Fungal diversity and its mechanism of community shaping in the milieu of sanitary landfill

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1370-6

摘要:

Ascomycota was the predominant phylum in sanitary landfill fungal communities.

关键词: Sanitary landfill     Fungal community     Diversity     Saprotroph     Physical habitat     Environmental factor    

Research on constraint-based virtual assembly technologies

YANG Rundang, WU Dianliang, FAN Xiumin, YAN Juanqi

《机械工程前沿(英文)》 2007年 第2卷 第2期   页码 243-249 doi: 10.1007/s11465-007-0043-5

摘要: To realize a constraint-based virtual assembly operation, the unified representations of the assembly constraint, the equivalent relation between the constraint and the degree of freedom (DOF), and the movement DOF reduction in a virtual environment are proposed. Several algorithms about the constraint treatment are submitted. First, the automatic recognition algorithm based on the assembly relation is used to determine the position and orientation relation between two geometry elements of constraint whether they meet the given errors. Second, to satisfy the new constraint, according to the positing solving algorithm, the position and orientation of an active part are modified with minimal adjustment after the part has satisfied the affirmed constraints. Finally, the algorithm of movement navigation based on the generalized coordinate system is put forward, and the part movement is guided. These algorithms have been applied to the integrated virtual assembly environment (IVAE) system. Experiments have indicated that these algorithms have well supported constraint treatments in the IVAE and realized the closer combination of the virtual and the real assembly processes.

关键词: movement DOF     recognition algorithm     assembly     orientation     combination    

contact analysis of planetary roller screw mechanism and its application in grouping for selective assembly

《机械工程前沿(英文)》 2024年 第19卷 第1期 doi: 10.1007/s11465-023-0775-x

摘要: The planetary roller screw mechanism (PRSM) is a novel precision transmission mechanism that realizes the conversion between linear and rotary motions. The contact characteristics of helical surfaces directly determine PRSM’s performance in load-carrying capacity and transmission accuracy. Therefore, studying the contact characteristics of PRSM forms the fundamental basis for enhancing its transmission performance. In this study, a three-dimensional parametric analysis method of contact characteristics is proposed based on the PRSM meshing principle and PyVista (a high-level API to the Visualization Toolkit). The proposed method considers the influence of machining errors among various thread teeth. The effects of key machining errors on contact positions and axial clearance, as well as their sensitivities, are analyzed. With excellent solution accuracy, this method exhibits higher calculation efficiency and stronger robustness than the analytical and numerical meshing models. The influence of nominal diameter and pitch errors of the screw, roller, and nut on the axial clearance follows a linear relationship, whereas flank angle errors have negligible effects on the axial clearance. The corresponding influence coefficients for these three machining errors on the axial clearance are 0.623, 0.341, and 0.036. The variations in contact positions caused by individual errors are axisymmetric. Flank angle errors and roller diameter errors result in linear displacements of the contact points, whereas pitch errors cause the contact points to move along the arc of the roller diameter. Based on the proposed three-dimensional parametric contact characteristics analysis method, the Fuzzy C-Means clustering algorithm considering error sensitivity is utilized to establish a component grouping technique in the selective assembly of critical PRSM components, ensuring the rational and consistent clearances based on the given component’s machining errors. This study provides effective guidance for analyzing contact characteristics and grouping in selective assembly for PRSM components. It also presents the proposed method’s potential applicability to similar calculation problems for contact positions and clearances in other transmission systems.

关键词: planetary roller screw mechanism (PRSM)     contact position     axial clearance     machining error     grouping for selective assembly    

A survey on assembly lines and its types

Ullah SAIF,Zailin GUAN,Baoxi WANG,Jahanzeb MIRZA,Shiyang HUANG

《机械工程前沿(英文)》 2014年 第9卷 第2期   页码 95-105 doi: 10.1007/s11465-014-0302-1

摘要:

Assembly lines are useful for mass production of standard as well as customized products. Line balancing is an important issue, in this regard an optimal or near optimal balance can provide a fruitful savings in the initial cost and also in the running cost of such production systems. A survey of different problems in different types of assembly lines and some of the critical and on going research areas are highlighted here. The provided research information is momentous for the research community in assembly line area to proceed further in the presented issues of assembly lines.

关键词: assembly lines     line balancing     survey    

Differences in distributions, assembly mechanisms, and putative interactions of AOB and NOB at a large

《环境科学与工程前沿(英文)》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1722-0

摘要:

● Nitrifiers in WWTP were investigated at large spatial scale.

关键词: Activated sludge     Spatial distributions     Microbial assembly     Co-occurrence patterns     Nitrifying bacteria    

The construction of pseudo-Janus silica/surfactant assembly and their application to stabilize Pickering

《化学科学与工程前沿(英文)》 2022年 第16卷 第7期   页码 1101-1113 doi: 10.1007/s11705-021-2095-1

摘要: Nanoparticles with high surface energy and chemical activity have drawn substantial attention in petroleum industry. Recently, Janus nanoparticles exhibited tremendous potential in enhanced oil recovery (EOR) due to their asymmetric structures and properties. In this study, a series of amphiphilic pseudo-Janus@OTAB (PJ@C18) nanoparticles with different concentrations of stearyltrimethylammoium bromide (OTAB) were successfully fabricated. The structures and properties of PJ@C18 were characterized by Fourier transform infrared spectroscopy and ζ-potential measurements. Based on the emulsification experimental results, the interaction models and the self-assembly behavior between hydrophilic nanoparticles (SiO2@NH2) and OTAB molecules at the oil/water interface were proposed, which was further confirmed via the measurements of the contact angle and dynamic interfacial tension. Interestingly, it was found that the change of pH value from 7.5 to 4.0 caused the type reversal of the PJ@C18-1000 stabilized Pickering emulsions. Furthermore, the PJ@C18-1000 stabilized Pickering emulsion system with excellent salt and temperature tolerances (10000 mg∙L–1, 90 °C) significantly improved the oil recovery in the single-tube (more than 17%) and double-tube (more than 25%) sand pack model flooding tests. The findings of this study could help to better understand the construction mechanism of pseudo-Janus silica/surfactant assembly and the potential application of PJ@C18-1000 stabilized Pickering emulsions for EOR.

关键词: Janus nanoparticles     surfactant     double phase inversion     self-assembly     enhanced oil recovery    

of different voltage application modes on biodegradation of chloramphenicol and shift of microbial community

《环境科学与工程前沿(英文)》 2022年 第16卷 第11期 doi: 10.1007/s11783-022-1576-x

摘要:

● Presented coupled system enhanced biodegradation of antibiotic chloramphenicol.

关键词: Electrical stimulation     Biodegradation     Microbial community     Chloramphenicol    

标题 作者 时间 类型 操作

Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare

期刊论文

Impacts of backwashing on micropollutant removal and associated microbial assembly processes in sand

期刊论文

Meter-scale variation within a single transect demands attention to taxon accumulation curves in riverine microbiome studies

期刊论文

Assembly of biosynthetic pathways in

Lidan Ye,Xiaomei Lv,Hongwei Yu

期刊论文

A novel task-oriented framework for dual-arm robotic assembly task

期刊论文

Pareto lexicographic α-robust approach and its application in robust multi objective assembly line balancing

null

期刊论文

Assembly design system based on engineering connection

Wensheng YIN

期刊论文

Enzyme-instructed self-assembly of peptides containing phosphoserine to form supramolecular hydrogels

Jie Zhou, Xuewen Du, Jiaqing Wang, Natsuko Yamagata, Bing Xu

期刊论文

Fungal diversity and its mechanism of community shaping in the milieu of sanitary landfill

期刊论文

Research on constraint-based virtual assembly technologies

YANG Rundang, WU Dianliang, FAN Xiumin, YAN Juanqi

期刊论文

contact analysis of planetary roller screw mechanism and its application in grouping for selective assembly

期刊论文

A survey on assembly lines and its types

Ullah SAIF,Zailin GUAN,Baoxi WANG,Jahanzeb MIRZA,Shiyang HUANG

期刊论文

Differences in distributions, assembly mechanisms, and putative interactions of AOB and NOB at a large

期刊论文

The construction of pseudo-Janus silica/surfactant assembly and their application to stabilize Pickering

期刊论文

of different voltage application modes on biodegradation of chloramphenicol and shift of microbial community

期刊论文