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China ADS sub-critical experimental assembly—Venus-1 and preliminary experiment

SHI Yongqian, XIA Pu, LUO Zhanglin, ZHAO Zhixiang, DING Dazhao, ZHU Qinfu, XIA Haihong, LI Jigen, ZHANG Wei, CAO Jian, QUAN Yanhui, LUO Huangda, WU Xiaofei

《能源前沿(英文)》 2007年 第1卷 第2期   页码 150-157 doi: 10.1007/s11708-007-0019-5

摘要: China s accelerator-driven sub-critical system (ADS) sub-critical experimental assembly Venus-1 and the preliminary experiment is presented. The core of Venus-1 is a coupled one of a fast neutron zone and a thermal neutron zone. The fast neutron zone is at the centre of the core and formed by natural uranium fuel. A fast neutron spectrum field can be produced in the fast neutron zone and used for the transmutation of minor actinides (MAs). The thermal neutron zone surrounds the fast neutron zone and is formed by low-enriched uranium fuel. It is a fission zone. An epithermal neutron zone between the fast neutron zone and the thermal neutron zone can be established for the transmutation of long-lived fission products (LLFP). On July 18, 2005, the first fuel element was loaded into the Venus-1 sub-critical assembly and some preliminary experiments about the sub-critical neutronics were performed. The Venus-1 can be driven by an Am-Be source or other steady neutron source (Cf-252, D-D reaction and D-T reaction) to study the effect of the external neutron source with different energies or a D-T pulsed neutron source on the dynamic characteristics.

关键词: coupled     D-D reaction     dynamic     pulsed neutron     sub-critical assembly    

The summary of researches on ADS in China

XIA Haihong, ZHAO Zhixiang, LI Jigen, SHI Yongqian, HAN Yinlu, ZHU Shengyun, XU Yongli, GUAN Xialing, CUI Baoqun, FU Shinian

《能源前沿(英文)》 2007年 第1卷 第2期   页码 135-140 doi: 10.1007/s11708-007-0017-7

摘要: The conceptual study on the accelerator driven system (ADS) that lasted for about five years ended in 1999 in China. As one project of the National Basic Research Program of China (973 Program) in the energy domain, which is sponsored by the China Ministry of Science and Technology (MOST), a five-year-program of fundamental research of ADS physics and related technology was launched in 2000 and passed national review at the end of 2005. The China Institute of Atomic Energy (CIAE), the Institute of High Energy Physics (IHEP), the Institute of Heavy Ion Physics in Peking University (PKU-IHIP) and other institutions jointly carried out the research. The research activities were focused on HPPA physics and technology, reactor physics of external source driven sub-critical assembly, nuclear data base and material study. For HPPA, a high current injector consisting of an ECR ion source, LEBT and an RFQ accelerating structure of 3.5 MeV was built. In reactor physics study, a series of neutron multiplication experimental study has been carried out and still being done. The VENUS facility has been constructed as the basic experimental platform for neutronics study in ADS blanket. It s a zero power sub-critical neutron multiplying assembly driven by external neutron produced by a pulsed neutron generator. The theoretical, experimental and simulation study on nuclear data, material properties and nuclear fuel circulation related to ADS is carrying on to provide the database for ADS system analysis. The main results on ADS related researches will be reported.

关键词: accelerator     national     multiplying assembly     sub-critical assembly     simulation    

An investigation into the heat transfer characteristics of spiral wall with internal rib in a supercritical sliding-pressure operation once-through boiler

TANG Renhu, YIN Fei, WANG Haijun, CHEN Tingkuan

《能源前沿(英文)》 2007年 第1卷 第3期   页码 300-304 doi: 10.1007/s11708-007-0043-5

摘要: Within the pressure range of 9–28 MPa, mass velocity range of 600–1 200 kg/(m · s), and heat flux range of 200–500 kW/m, experiments were performed to investigate the heat transfer to water in the inclined upward internally ribbed tube with an inclined angle of 19.5 degrees, a maximum outer diameter of 38.1 mm, and a thickness of 7.5 mm. Based on the experiments, it was found that heat transfer enhancement of the internally ribbed tube could postpone departure from nucleate boiling at the sub-critical pressure. However, the heat transfer enhancement decreased near the critical pressure. At supercritical pressure, the temperature difference between the wall and the fluid increased near the pseudo-critical temperature, but the increase of wall temperature was less than that of departure from nucleate boiling at sub-critical pressure. When pressure is closer to the critical pressure, the temperature difference between the wall and the fluid increased greatly near the pseudo-critical temperature. Heat transfer to supercritical water in the inclined upward internally ribbed tube was enhanced or deteriorated near the pseudo-critical temperature with the variety of ratio between the mass velocity and the heat flux. Because the rotational flow of the internal groove reduced the effect of natural convection, the internal wall temperature of internally ribbed tube uniformly distributed along the circumference. The maximum internal wall temperature difference of the tube along the circumference was only 10 degrees when the fluid enthalpy exceeded 2 000 J/g. Considering the effect of acute variety of the fluid property on heat transfer, the correlation of heat transfer coefficient on the top of the internally ribbed tube was provided.

关键词: m ·     diameter     critical pressure     sub-critical pressure     maximum    

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

WANG Fenghao, JIANG Gedong, Lin John Zhang

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

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

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

Greenhouse gas emissions from different pig manure management techniques: a critical analysis

Conor Dennehy, Peadar G. Lawlor, Yan Jiang, Gillian E. Gardiner, Sihuang Xie, Long D Nghiem, Xinmin Zhan

《环境科学与工程前沿(英文)》 2017年 第11卷 第3期 doi: 10.1007/s11783-017-0942-6

摘要: Manure management is the primary source of greenhouse gas (GHG) emissions from pig farming, which in turn accounts for 18% of the total global GHG emissions from the livestock industry. In this review, GHG emissions (N O and CH emissions in particular) from individual pig manure (PGM) management practices (European practises in particular) are systematically analyzed and discussed. These manure management practices include manure storage, land application, solid/liquid separation, anaerobic digestion, composting and aerobic wastewater treatment. The potential reduction in net GHG emissions by changing and optimising these techniques is assessed. This review also identifies key research gaps in the literature including the effect of straw covering of liquid PGM storages, the effect of solid/liquid separation, and the effect of dry anaerobic digestion on net GHG emissions from PGM management. In addition to identifying these research gaps, several recommendations including the need to standardize units used to report GHG emissions, to account for indirect N O emissions, and to include a broader research scope by conducting detailed life cycle assessment are also discussed. Overall, anaerobic digestion and compositing to liquid and solid fractions are best PGM management practices with respect to their high GHG mitigation potential.

关键词: CH4     N2O     Storage     Anaerobic digestion     Composting     Separation    

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    

Biodiesel production from waste frying oil in sub- and supercritical methanol on a zeolite Y solid acid

Jorge MEDINA-VALTIERRA, Jorge RAMIREZ-ORTIZ

《化学科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 401-407 doi: 10.1007/s11705-013-1354-1

摘要: Waste frying oil (WFO) is a very important feedstock for obtaining biodiesel at low cost and using WFO in transesterification reactions to produce biodiesel helps eliminate local environmental problems. In this study biodiesel was produced from WFO in sub- and super-critical methanol on a zeolite Y solid acid catalyst. The procedure was optimized using a design of experiments by varying the methanol to WFO molar ratio, the reaction temperature, and the amount of catalyst. Typical biodiesel yields varied from 83 to nearly 100% with methyl esters content ranging from 1.41–1.66 mol·L and typical dynamic viscosities of 22.1-8.2 cP. Gas chromatography was used to determine the molecular composition of the biodiesel. The reaction products contained over 82 wt-% methyl esters, 4.2 wt-% free acids, 13.5 wt-% monoglycerides, and 0.3 wt-% diglycerides. The transesterification of WFO with methanol around its critical temperature combined with a zeolite Y as an acid catalyst is an efficient approach for the production of biodiesel with acceptable yields.

关键词: biodiesel     methanol     critical temperature     waste frying oil     zeolite Y    

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    

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    

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    

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    

标题 作者 时间 类型 操作

China ADS sub-critical experimental assembly—Venus-1 and preliminary experiment

SHI Yongqian, XIA Pu, LUO Zhanglin, ZHAO Zhixiang, DING Dazhao, ZHU Qinfu, XIA Haihong, LI Jigen, ZHANG Wei, CAO Jian, QUAN Yanhui, LUO Huangda, WU Xiaofei

期刊论文

The summary of researches on ADS in China

XIA Haihong, ZHAO Zhixiang, LI Jigen, SHI Yongqian, HAN Yinlu, ZHU Shengyun, XU Yongli, GUAN Xialing, CUI Baoqun, FU Shinian

期刊论文

An investigation into the heat transfer characteristics of spiral wall with internal rib in a supercritical sliding-pressure operation once-through boiler

TANG Renhu, YIN Fei, WANG Haijun, CHEN Tingkuan

期刊论文

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

WANG Fenghao, JIANG Gedong, Lin John Zhang

期刊论文

Greenhouse gas emissions from different pig manure management techniques: a critical analysis

Conor Dennehy, Peadar G. Lawlor, Yan Jiang, Gillian E. Gardiner, Sihuang Xie, Long D Nghiem, Xinmin Zhan

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

Biodiesel production from waste frying oil in sub- and supercritical methanol on a zeolite Y solid acid

Jorge MEDINA-VALTIERRA, Jorge RAMIREZ-ORTIZ

期刊论文

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

期刊论文

Research on constraint-based virtual assembly technologies

YANG Rundang, WU Dianliang, FAN Xiumin, YAN Juanqi

期刊论文

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

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