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1.
A large-scale high-precision scan stage is important equipment in the industrial productions of micro-fabrication such as flat panel display (FPD) lithography systems. Designing controllers for multi-input multi-output (MIMO) systems is time-consuming and needs experience because of the interaction between each axis and many controller tuning parameters. The aim of this study is to develop a peak filter design method based on frequency response data to reduce repetitive disturbance. This data-based approach does not use the model and only uses the frequency response data of the controlled system and the disturbance spectrum calculated from the scanning error data (Contribution 1). The peak filter is designed by convex optimization and satisfies robust stability conditions for six-degree-of-freedom systems (Contribution 2). The control performance of the designed peak filter is experimentally demonstrated with an industrial MIMO large-scale high-precision scan stage in reducing the scanning error of the main stroke of the translation along the x-axis (Contribution 3).  相似文献   
2.
In response to the growing interest in offshore wind energy development in California, the U.S. Bureau of Ocean Energy Management delineated three Call Areas for potential leasing. This study provides a comprehensive characterization and comparison of offshore wind power potential within the two Central California Call Areas (Diablo Canyon and Morro Bay) using 12- and 15-MW turbines under different inter-turbine spacing and wind farm size scenarios. Our analysis shows similar daily and seasonal patterns of wind power produced within the Call Areas, which peak in spring and during evening hours. Per-turbine power production is higher in the Morro Bay Call Area due to slightly higher hub-height wind speeds, whereas total power production is higher in the Diablo Canyon Call Area due to its larger size. Turbine type had a negligible impact on average power production per-unit-area because while larger turbines produce more power, they require greater inter-turbine spacing. Combined power production from the two fully built out Call Areas could equal nearly a quarter of California's current annual electrical energy production. A commercial-scale wind farm with a realized power output of 960 MW would require a footprint of at least half of the Morro Bay Call Area or at least a quarter of the Diablo Canyon Call Area. These results provide guidance on offshore wind development over the Central California Coast, and the framework demonstrated here could be applied to other wind data sets in other regions.  相似文献   
3.
为了准确施加斜拉桥的恒载初始索力,提出了一种基于ANSYS平台控制温度索力迭代施加的方法,从而精确施加斜拉桥初始成桥索力.以设计索力作为目标值,考虑斜拉桥几何非线性因素,初始索力以初始温度的形式施加到斜拉索上,运用APDL二次开发软件编制了斜拉桥成桥索力迭代计算程序,并将该程序应用于双塔双索面钢-混凝土叠合梁斜拉桥结构分析中.结果表明,桥塔两侧斜拉索的计算索力与目标索力误差均在5%以内,该初始索力迭代方法具有方便快捷和效率高的优点.  相似文献   
4.
针对超高强钢在机械行业的广泛使用,焊接接头易出现淬硬脆化、裂纹等缺陷的情况,采用焊条电弧焊(SMAW)和药芯气体保护焊(FCAW-GS)组合的焊接方法,对API X52管线钢与Corus RQT 701超高强钢的焊接进行了工艺试验,并进行常规力学性能试验。结果表明,通过合理匹配焊接工艺参数,严格控制低热输入量及层间温度,实现了小熔合比的异种钢焊接,且焊接接头具有良好的力学性能,达到了标准和规格书的要求;异种高强钢焊接,采用SMAW打底焊接和FCAWGS填充并盖面的方法,焊接效率较单纯采用焊条电弧焊工艺提高2倍以上。  相似文献   
5.
This paper introduces an efficient algorithm for the bike request scheduling problem (BRSP). The BRSP is built around the concept of request, defined as the pickup or dropoff of a number of identical items (bikes) at a specific station, within a certain time window, and with a certain priority. The aim of the BRSP is to sequence requests on (and hence determine the routes of) a set of vehicles, in such a way that the sum of the priorities of the executed requests is maximized, all time windows are respected, and the capacity of the vehicles is not exceeded. The generation of the set of requests is explicitly not a part of the problem definition of the BRSP. The primary application of the BRSP, from which it derives its name, is to determine the routes of a set of repositioning vehicles in a bike sharing system, although other applications exist. The algorithm introduced in this paper is based on a set of related greedy randomized adaptive search procedure followed by variable neighborhood descent (GRASP + VND) operators embedded in a large neighborhood search (LNS) framework. Since this paper presents the first heuristic for the BRSP, a computational comparison to existing approaches is not possible. We therefore compare the solutions found by our LNS heuristic to those found by an exact solver (Gurobi). These experiments confirm that the proposed algorithm scales to realistic dimensions and is able to find near‐optimal solutions in seconds.  相似文献   
6.
The paper presents in-depth three-dimensional finite element analyses investigating geosynthetic-reinforced soil walls with turning corners. Validation of the 3D numerical procedure was first performed via comparisons between the simulated and reported results of a benchmark physical modeling built at the Royal Military College of Canada. GRS walls with corners of 90°, 105°, 120°, 135°, 150°, and 180° were simulated adopting the National Concrete Masonry Association guidelines. The behaviors of the GRS walls with corners, including the lateral facing displacement, maximum reinforcement load, factor of safety, potential failure surface, vertical separation of facing blocks, and types of corners were carefully evaluated. Our comprehensive results show (i) minimum lateral displacement occurs at the corner; (ii) lower strength of reinforcements are required at the corner; (iii) higher corner angles lead to lower stability; (iv) potential failure surface forms earlier at the end walls; (v) deeper potential failure surfaces are found at the corners; (vi) larger numbers of vertical separations are found at walls with smaller corner angles. The paper highlighted the salient influence of the corners on the behaviors of GRS walls and indicated that a 3D analysis could reflect the required reinforcement length and the irregular formation of the potential failure surfaces.  相似文献   
7.
Crushable volcanic soils are well-known for their distinctive texture, vesicular nature and grain fragility. These features of volcanic soils lead to difficulty in interpreting the results of laboratory and field testing because of the occurrence of particle crushing. Sands containing pumice particles are commonly found in the Hamilton Basin in the North Island of New Zealand. The pumice particles originated from a series of volcanic eruptions centered in the Taupo and Rotorua regions. As a result of flooding and erosion along the Waikato River, the pumice particles have become mixed with other materials and have been distributed over the Hamilton Basin; these mixtures are referred to herein as natural pumiceous (NP) sands. This paper initially investigates an appropriate technique for measuring the maximum dry density (MDD) of NP sands; then a modified MDD test is proposed for estimating the pumice contents of these sands. In order to examine the applicability of different standard methods for determining MDD, New Zealand and Japanese standards are employed. The results using the Japanese standard show consistent MDD values when repeating the tests due to negligible particle crushing. On the other hand, the results of MDD tests according to the New Zealand standard indicate that a significant amount of particle crushing occurs after each repeated test and, consequently, it is not possible to get the same result when the test is repeated. NP sands reach their ultimate potential breakage during the modified MDD tests (at least, for the level of loading applied) and they experience different levels of particle crushing which may be a function of their pumice content. As a way forward, the relative breakages of the materials tested are used to estimate the pumice contents of the NP sands.  相似文献   
8.
以新疆多浪羊为研究对象,对比分析传统屠宰(对照)和3个不同电压(90、127 V和220 V)击晕屠宰(分别计作EST 90、EST 127、EST 220)对多浪羊肉品质的影响。结果表明:EST 90处理组成熟过程中p H值下降速率最快,血液中的皮质醇浓度、肌酸激酶和乳酸脱氢酶活力最高,羊应激反应最剧烈,宰后1、7 d的蒸煮损失率最高(P0.05);EST 127处理组的持水力最好;电击晕对多浪羊肉嫩度有一定影响,宰后7 d各处理组嫩度显著改善,而EST 127处理组表现最佳;EST 220处理组放血不充分,且胴体表皮有多处血斑形成;电击晕屠宰对多浪羊肉色泽无显著影响(P0.05)。综合分析实验结果,EST 127处理组持水力与嫩度较优,羊应激反应较小,肉品质相对较好,因此EST 127处理适合应用于多浪羊的屠宰加工。  相似文献   
9.
国内电力工程项目质量管理普遍存在项目多、资源少、监管难、风险大等问题,往往不能及时发现质量隐患、预防质量事故。文章立足于电力工程企业,从加强电力工程项目质量监管入手,比较传统质量巡查和第三方质量巡查两种模式,阐述引入第三方质量巡查机制的操作流程及注意事项,并结合实例分析第三方质量巡查机制的应用效果和在电力工程企业质量管理中的推广价值。  相似文献   
10.
以业务流程再造、程序分析等相关理论方法为基础,以J市R医院消化内科为例,对医院门诊就诊流程进行优化研究。通过实地走访与问卷调查发现消化内科现行门诊服务流程中存在的问题,基于业务流程再造理论优化门诊服务流程,使用程序分析方法和Flexsim仿真对门诊就诊流程进行对比分析,验证了优化方案的有效性。  相似文献   
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