首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A novel subject-delineation strategy has been developed for the retrieval of the core literature in bioinformatics. The strategy combines textual components with bibliometric, citation-based techniques. This bibliometrics-aided search strategy is applied to the 1980–2004 annual volumes of the Web of Science. Retrieved literature has undergone a structural as well as quantitative analysis. Patterns of national publication activity, citation impact and international collaboration are analysed for the 1990s and the new millennium.  相似文献   

2.
Jun W  Asundi A 《Applied optics》2002,41(34):7229-7236
A novel fringe processing method is proposed to segment whole-field strain distributions from interferometric deformation patterns by use of Gabor filters. This novel strategy is specifically proposed for strain measurement with a Gabor filter used as a set of wavelets. To increase computational speed as well as for selection of contour intervals, judicious design of the filter bank, based on the fringe pattern and the requirements of the user, is crucial in this methodology. A filter design strategy is developed and, based on the proposed filter design scheme, properly designed filter banks are generated and applied for strain contouring in low-strain and strain concentration regions. This scheme allows one to measure engineering strains within regions of interest and hence provides the design engineer great flexibility of monitoring, testing, or analysis.  相似文献   

3.
Nature and organism often use the biomineralization technique to build up various highly regular structures such as bone, teeth, kidney stone etc., and recently this becomes the strategy to design and synthesis of novel biocomposite materials. We report here the controlled crystallization of KCl in Langmuir and Langmuir Blodgett (LB) monolayer of Hemoglobin (Hb) at ambient condition. The nucleation and growth of KCl crystals in Hb monolayer has temporal and KCl concentration dependency. The growth of KCl crystals in LB film of Hb has distinct behavior in the alignment of crystals from linear to fractal like structures depending on growth time. The crystallographic identity of the biomineralized KCl crystal is confirmed from HR-TEM, XRD, and from powder diffraction simulation. Our results substantiated that the template of Langmuir monolayer of proteins plays a crucial role in biomineralization as well as in designing and synthesizing of novel biocomposite materials.  相似文献   

4.
Bowman MJ  Zaia J 《Analytical chemistry》2007,79(15):5777-5784
Although stable isotopic labeling has found widespread use in the proteomics field, its application to carbohydrate quantification has been limited. Herein we report the design, synthesis, and application of a novel series of compounds that allow for the incorporation of isotopic variation within glycan structures. The novel feature of the compounds is the ability to incorporate the isotopes in a controlled manner, allowing for the generation of four tags that vary only in their isotopic content. This allows for the direct comparisons of three samples or triplicate measurements with an internal standard within one mass spectral analysis. Quantitation of partially depolymerized glycosaminoglycan mixtures, as well as N-linked glycans released from fetuin, is used to demonstrate the utility of the tetraplex tagging strategy.  相似文献   

5.
一种新型并联XYY微定位平台动力学建模及控制仿真   总被引:1,自引:1,他引:0       下载免费PDF全文
舒强  施宁平  饶学军  郭友明   《振动与冲击》2012,31(8):130-135,147
介绍了一种新型的压电陶瓷驱动的并联XYY结构微定位平台。该平台通过Y方向两个压电驱动器的实时校正,能够避免因加工装配误差引起的结构非对称性对平台运动直线度的影响。推导了微定位平台的动力学模型。通过引入过程噪声的数学模型增广LQG控制器,实现了微定位平台解耦和跟踪,仿真发现这种方法能够有效抑制窄带随机扰动,提高定位精度。  相似文献   

6.
本文研制一种用于超高密度数据存储的硅基纳机电探针阵列器件.简要介绍了器件结构及其工作原理,并通过理论计算和有限元模拟相结合的方法实现器件的结构设计.并运用先进的微纳加工工艺技术制造出相应的器件,具体包括:先进的纳米硅尖制造技术、高电隔离性的加热电阻制作技术及其纳机电探针上加热电阻与压阻传感器集成技术等.室温下,测得该器件加热电阻器的阻值为(500~600) Ω,压阻传感器的阻值为(6~8) KΩ,在2×10-7 N预力作用于针尖处时,悬臂梁上的压阻器件灵敏度(电阻相对变化)达到了3.12×10-4,满足纳米数据坑读出对于灵敏度要求;纳米针尖曲率半径小于40 nm,满足器件高密度存储对于硅尖要求.建立一套适用于该纳机电探针的电热理论模型,利用该模型计算的结果与器件电热测试结果相吻合.  相似文献   

7.
In order to take advantage of the specific structural and functional properties inside a multi‐material assembly, it is necessary to provide adapted joining technologies. Therefore, the new joining technology “thermoclinching” was developed to join endless fiber reinforced thermoplastic composites and metallic joining partners. Previous experimental and numerical studies demonstrated the potential of the novel joining technology. In experimental and numerical studies essential geometrical and material parameters influencing the forming behavior are identified and evaluated. Thereby, the inline‐thermoclinching technology is developed by integrating the pre‐processed steps of cutting and heating into the actual joining process. For structural analysis of the joining zone as well as for quality analysis and validation of the process simulations computer tomography (CT) is used. Furthermore, experimental characterizations of the failure behavior of thermoclinched joints and the development of simulation models as well as strategies for numerical strength analyses are carried out.  相似文献   

8.
This paper describes a modified extended finite element method (XFEM) approach, which is designed to ease the challenge of an analytical design sensitivity analysis in the framework of structural optimisation. This novel formulation, furthermore labelled YFEM, combines the well‐known XFEM enhancement functions with a local sub‐meshing strategy using standard finite elements. It deviates slightly from the XFEM path only at one significant point but thus allows to use already derived residual vectors as well as stiffness and pseudo load matrices to assemble the desired information on cut elements without tedious and error‐prone re‐work of already performed derivations and implementations. The strategy is applied to sensitivity analysis of interface problems combining areas with different linear elastic material properties. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

9.
采用一种基于高分子Monte Carlo模拟算法分析分子蠕动阻力的软件,借助于二维空间中的8配位点键长涨落的格子链模型,对不同温度、分子量、共混小分子时的大分子蠕动行为进行了模拟分析,考察了温度、分子长、共混小分子等因素对蠕动阻力的影响,得到了随着温度增加、分子长减小和共混浓度增加,大分子蠕动阻力减小的结果,这与传统经验理论相符合。这些结果为选择大分子量添加剂黄原胶作为抗结块剂,以及选择β-环糊抑制玻璃化转变等提供了理论依据。  相似文献   

10.
Process analysis is recognized as a major stage in business process reengineering that has developed over the last two decades. Manufacturing process analysis (MPA) is defined as performance analysis of the production process. A manufacturing process analysis framework is outlined with emphasis on linking a company's strategy to operational process. Two issues, namely process modelling and simulation based analysis, are investigated. A compound workflow model (CWM) is proposed to provide graphic presentation of the production process that can be easily understood. Also it can be used directly by simulation to study the impacts of scheduling policy and analyse the process performance. A two-stage simulation analysis method is provided to quantitatively and efficiently define cause-and-effect relations to identify drivers for improvement. The manufacturing environment, PSC (production planning, scheduling and control) factors and the process structure are three main concerns considered in the simulation. An example is discussed in the final part of the paper.  相似文献   

11.
The importance of augmenting human-technology collaborative cognition has been envisioned as one of the fundamental ways to bolster human cognition through human-automation interaction in complex manufacturing and operational environments. The focus on collaborative cognition entails a human-automation mutual adaption strategy for augmenting team cognition and collective intelligence. This paper provides an overview of augmenting collaborative cognition from an analytic and model-based decision-making perspective. Aiming to advance basic research for understanding human cognition augmentation, the fundamental and applied aspects of creating mathematical and computational models are discussed in regard to cognitive state sensing and assessment, human-automation interaction adaption and control, as well as group decision making in human-automation systems. A research roadmap towards cyber-physical-human analysis is deliberated to reveal a variety of opportunities of developing novel methods for enhancing affective cognition and perception learning, trust dynamics modelling, human cognitive performance prediction, as well as human-automation interaction optimisation.  相似文献   

12.
Mechanical mechanisms with clearance abound in technological fields such as robotics, machine and steam turbine industry. The dynamic performance of these mechanisms in working condition can be achieved provided that the effects of the different on the mechanisms (such as mechanism dynamics, technological effects and thermal behaviour) are thoroughly understood. Virtual prototyping provides an integration of multi-domain dynamic simulation for the design and analysis process. In the current paper, a framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance is presented. A case study with such a simulation strategy is studied for the optimum design and analysis of the technological parameter.  相似文献   

13.
Mechanical mechanisms with clearance abound in technological fields such as robotics, machine and steam turbine industry. The dynamic performance of these mechanisms in working condition can be achieved provided that the effects of the different on the mechanisms (such as mechanism dynamics, technological effects and thermal behaviour) are thoroughly understood. Virtual prototyping provides an integration of multi-domain dynamic simulation for the design and analysis process. In the current paper, a framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance is presented. A case study with such a simulation strategy is studied for the optimum design and analysis of the technological parameter.  相似文献   

14.
认知无线电系统中的两判决门限能量检测算法   总被引:2,自引:0,他引:2  
基于传统单门限能量检测算法,提出了一种适用于认知无线电系统的两门限能量检测算法.在算法分析中定义了两个性能指标,即认知用户和主用户间的碰撞概率以及限制认知用户对频谱使用的限占概率.理论分析与仿真结果表明,与传统单门限能量检测算法相比较,两门限能量检测算法降低了认知用户和主用户间的碰撞概率,同时也引起限占概率的增加,即该算法能够在牺牲部分频谱效率的条件下,明显降低认知用户对主用户的干扰,保证了主用户使用频谱的优先权.  相似文献   

15.
Monte Carlo simulation of the field back-scattered from rough surfaces   总被引:1,自引:0,他引:1  
A novel approach for the simulation of the field back-scattered from a rough surface is presented. It takes into account polarization and multiple scattering events on the surface, as well as diffraction effects. The validity and usefulness of this simulation is demonstrated in the case of surface topology measurement.  相似文献   

16.
大跨度斜拉桥Benchmark问题的振动控制研究是当前国际结构控制研讨会的重要议题之一。以美国Bill Emerson Memorial斜拉桥第二阶段Benchmark模型为研究对象,在非线性随机动力学与控制的拟哈密顿理论体系框架下,运用基于随机平均法和随机动态规划原理的非线性随机最优(NSO)控制策略,对地震作用下的Benchmark模型进行MATLAB仿真分析。将最优控制力和性能评价指标与线性二次型Gauss(LQG)控制的计算结果进行对比,得出非线性随机最优控制策略能够更加有效地抑制斜拉桥的地震响应,提高结构的动力稳定性和抗震能力,具有更好的控制效果,对实际桥梁工程的振动控制具有较强的指导意义和适用价值。  相似文献   

17.
王晨  尹静  王红春 《包装工程》2020,41(3):170-175
目的提高电商物流配送中心订单的分拣效率和动态响应能力。方法通过分析零售电商订单的多品种、小批量和高时效等特征,考虑分拣机器人动作与载重约束,提出了滚动时窗调度策略和高维稀疏动态聚类算法,并以某大型电商企业配送中心建立仿真实验模型,进行数据对比分析。结果以某大型电商某日高峰时段500个订单进行仿真实验,与固定组批分拣策略进行对比,优化后的分拣策略在机器人平均搬运距离上减少了66.9%,分拣时间降低了23.9%。结论高维稀疏动态聚类策略有效提高了分拣效率,降低了分拣成本,算法方式更加开放灵活,对于电商企业物流业务降本增效具有重要意义。  相似文献   

18.
This paper reexamines the order picking process in a warehouse facing the challenges that e-commerce brings about and which are characterised by a very large number of small sized orders and returns. Implementing effective storage assignment strategies combined with efficient batching, in this context, is very fundamental to keep the warehouse’s responsiveness and order completion times up to the standards. This paper investigates a new storage assignment strategy, initially implemented by a large shoes and footwear wholesaler, to enhance the performance of the order picking process in its warehouses. The impact of this new storage assignment strategy on the performance of the order picking process is analysed via simulation. The performance of the system, measured in terms of total picking time as well as order lead time while taking congestion into account, is compared to the cases where conventional storage assignment strategies are implemented. A full factorial design is set up and the simulation output is statistically analysed. The results of this analysis are reported and thoroughly discussed. Attending to the results, the proposed strategy presents a remarkable potential to shorten total picking travel distances and order completion time and consequently customer satisfaction.  相似文献   

19.
This paper deals with formal and simulation-based verification methods of a PRImary-to-SEcondary leaking (abbreviated as PRISE) safety procedure. The PRISE safety procedure controls the draining of the contaminated water in a faulty steam generator when a non-compensable leaking from the primary to the secondary circuit occurs. Because of the discrete nature of the verification, a Coloured Petri Net (CPN) representation is proposed for both the procedure and the plant model. We have proved by using a non-model-based strategy that the PRISE safety procedure is safe, there are no dead markings in the state space, and all transitions are live; being either impartial or fair.Further analysis results have been obtained using a model-based verification approach. We created a simple, low dimensional, nonlinear dynamic model of the primary circuit in a VVER-type pressurized water nuclear power plant for the purpose of the model-based verification. This is in contrast to the widely used safety analysis that requires an accurate detailed model. Our model also describes the relevant safety procedures, as well as all of the major leaking-type faults. We propose a novel method to transform this model to a CPN form by discretization. The composed plant and PRISE safety procedure system has also been analysed by simulation using CPN analysis tools. We found by the model-based analysis—using both single and multiple faults—that the PRISE safety procedure initiates the draining when the PRISE event occurs, and no false alarm will be initiated.  相似文献   

20.
DFT的装配车间生产物流策略仿真与研究   总被引:1,自引:0,他引:1  
张新艳  周健 《工业工程》2007,10(5):114-118
针对某汽车部件的实际装配生产,运用离散事件仿真的方法对基于需求流动技术(DFT)的装配生产物流策略进行了研究.在分析该汽车部件装配生产流程的基础上,确定eM-Plant仿真软件中的建模对象与装配生产系统中实体对象的对应关系,使用面向对象的方法建立了相应的离散事件仿真模型.在模型中分别实施基于推式生产方式的物流策略和基于DFT的物流策略,以该汽车部件的平均日产量为绩效指标,比较了两种物流策略对装配生产的影响.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号