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Cookie Baking Process Optimization and Quality Analysis Based on Food 3D Printing
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作者 Liu Chenghai Li Jingyi +2 位作者 Wu Chunsheng Zhao Xinglong Zheng Xianzhe 《Journal of Northeast Agricultural University(English Edition)》 CAS 2024年第1期61-73,共13页
In order to obtain better quality cookies, food 3D printing technology was employed to prepare cookies. The texture, color, deformation, moisture content, and temperature of the cookie as evaluation indicators, the in... In order to obtain better quality cookies, food 3D printing technology was employed to prepare cookies. The texture, color, deformation, moisture content, and temperature of the cookie as evaluation indicators, the influences of baking process parameters, such as baking time, surface heating temperature and bottom heating temperature, on the quality of the cookie were studied to optimize the baking process parameters. The results showed that the baking process parameters had obvious effects on the texture, color, deformation, moisture content, and temperature of the cookie. All of the roasting surface heating temperature, bottom heating temperature and baking time had positive influences on the hardness, crunchiness, crispiness, and the total color difference(ΔE) of the cookie. When the heating temperatures of the surfac and bottom increased, the diameter and thickness deformation rate of the cookie increased. However,with the extension of baking time, the diameter and thickness deformation rate of the cookie first increased and then decreased. With the surface heating temperature of 180 ℃, the bottom heating temperature of 150 ℃, and baking time of 15 min, the cookie was crisp and moderate with moderate deformation and uniform color. There was no burnt phenomenon with the desired quality. Research results provided a theoretical basis for cookie manufactory based on food 3D printing technology. 展开更多
关键词 food 3D printing baking process COOKIE quality analysis optimization of process parameter
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Multi-parameters uncertainty analysis of logistic support process based on GERT 被引量:7
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作者 Yong Wu Xing Pan +2 位作者 Rui Kang Congjiao He Liming Gong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第6期1011-1019,共9页
The uncertainty analysis is an effective sensitivity analysis method for system model analysis and optimization. However,the existing single-factor uncertainty analysis methods are not well used in the logistic suppor... The uncertainty analysis is an effective sensitivity analysis method for system model analysis and optimization. However,the existing single-factor uncertainty analysis methods are not well used in the logistic support systems with multiple decision-making factors. The multiple transfer parameters graphical evaluation and review technique(MTP-GERT) is used to model the logistic support process in consideration of two important factors, support activity time and support activity resources, which are two primary causes for the logistic support process uncertainty. On this basis,a global sensitivity analysis(GSA) method based on covariance is designed to analyze the logistic support process uncertainty. The aircraft support process is selected as a case application which illustrates the validity of the proposed method to analyze the support process uncertainty, and some feasible recommendations are proposed for aircraft support decision making on carrier. 展开更多
关键词 logistic support process uncertainty analysis graphi-cal evaluation and review technique(GERT) sensitivity analysis
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Machine learning based online fault prognostics for nonstationary industrial process via degradation feature extraction and temporal smoothness analysis 被引量:2
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作者 HU Yun-yun ZHAO Chun-hui KE Zhi-wu 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第12期3838-3855,共18页
Fault degradation prognostic, which estimates the time before a failure occurs and process breakdowns, has been recognized as a key component in maintenance strategies nowadays. Fault degradation processes are, in gen... Fault degradation prognostic, which estimates the time before a failure occurs and process breakdowns, has been recognized as a key component in maintenance strategies nowadays. Fault degradation processes are, in general,slowly varying and can be modeled by autoregressive models. However, industrial processes always show typical nonstationary nature, which may bring two challenges: how to capture fault degradation information and how to model nonstationary processes. To address the critical issues, a novel fault degradation modeling and online fault prognostic strategy is developed in this paper. First, a fault degradation-oriented slow feature analysis(FDSFA) algorithm is proposed to extract fault degradation directions along which candidate fault degradation features are extracted. The trend ability assessment is then applied to select major fault degradation features. Second, a key fault degradation factor(KFDF) is calculated to characterize the fault degradation tendency by combining major fault degradation features and their stability weighting factors. After that, a time-varying regression model with temporal smoothness regularization is established considering nonstationary characteristics. On the basis of updating strategy, an online fault prognostic model is further developed by analyzing and modeling the prediction errors. The performance of the proposed method is illustrated with a real industrial process. 展开更多
关键词 fault prognostic NONSTATIONARY industrial process fault degradation-oriented slow feature analysis(FDSFA) temporal smoothness regularization
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Comparative Proteomic Analysis of the Fiber Elongating Process in Cotton 被引量:1
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作者 LIU Jin-yuan,YANG Yi-wei,BIAN Shao-min(Laboratory of Molecular Biology,Department of Biological Sciences and Biotechnology,Tsinghua University,Beijing 100084,China) 《棉花学报》 CSCD 北大核心 2008年第S1期58-,共1页
A comparative proteomic analysis was performed to explore the mechanism of cell elongation in developing cotton fibers.The temporal changes of global proteomes at five representative
关键词 Comparative Proteomic analysis of the Fiber Elongating process in Cotton
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Decentralized Fault Diagnosis of Large-scale Processes Using Multiblock Kernel Principal Component Analysis 被引量:23
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作者 ZHANG Ying-Wei ZHOU Hong QIN S. Joe 《自动化学报》 EI CSCD 北大核心 2010年第4期593-597,共5页
关键词 分散系统 MBKPCA SPF PCA
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Integrated Process Capability Analysis
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作者 Chen H T Huang M L +1 位作者 Hung Y H Chen K S 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期193-,共1页
Process Capability Analysis (PCA) is a powerful too l to assess the ability of a process for manufacturing product that meets specific ations. The larger process capability index implies the higher process yield, a nd... Process Capability Analysis (PCA) is a powerful too l to assess the ability of a process for manufacturing product that meets specific ations. The larger process capability index implies the higher process yield, a nd the larger process capability index also indicates the lower process expected loss. Chen et al. (2001) has applied indices C pu, C pl, and C pk for evaluating the process capability for a multi-process product wi th smaller-the-better, larger-the-better, and nominal-the-best specificati ons respectively. However, C pk cannot reasonably reflect the process expected loss. In this paper, index C pn is selected to replace C pk. Indices C pu, C pl, and C pn are used to evalu ate the entire process capability for a multi-process product with smaller-the -better, larger-the-better, and nominal-the-best specifications respectivel y. An integrated process capability index for a multi-process product is propo sed. The relationship between process capability index and the process yield is introduced. A multi-process capability analysis chart (MPCAC), reasonably rev ealing the status of process capability for the entire product, is constructed f or practical application. An evaluating procedure of the process capability for the entire product is also provided. 展开更多
关键词 process capability indices integrated capability analysis process yield
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Comprehensive Evaluation of Processing Quality of Tibetan Native Hulless Barley Variety by Factor Analysis
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作者 Jin Yu-long Bai Ting +5 位作者 Zhang Yu-hong Zhu Ming-xia Zhang Zhi-wei Wang Shan-shan Liu Xiao-jiao Jia Fu-chen 《Journal of Northeast Agricultural University(English Edition)》 CAS 2021年第2期61-68,共8页
The purpose of this study was to explore the quality of the Tibetan native hulless barley variety in depth and to evaluate the characteristics of its processing quality using ratio analysis.For this study,10 native ba... The purpose of this study was to explore the quality of the Tibetan native hulless barley variety in depth and to evaluate the characteristics of its processing quality using ratio analysis.For this study,10 native barley varieties were chosen with the detection of 24 quality indexes in order to build a system of comprehensive evaluation.The results of the factor analysis indicated that seven common factors with an eigenvalue greater than 1 were extracted,cumulatively accounting for 96.21%of the total variance.The first common factor,including ASP,GLU,SER,GLY,ARG,TYR and CYS contents,accounted for 33.82% of the variance.The second common factor,including ash,the total starch,soluble fiber,VB_(3),Cu,Mn,Na and beta-glucan contents,accounted for 19.46%of the variance.The third common factor,including the total dietary fiber,α-VE,K,Zn and glutelin.The fourth common factor,including B,Ba and prolamin,explained the barley starch character of the rheological property.The fifth common factor included crude fiber.The sixth and the seventh common factors did not account for a substantial amount of variance.According to the comprehensive evaluation model,the score consequence was as the following:Zangqing25>Pengnaigabu>Lhasa changhei>2004Qing21>Lhasa duanbai>Liangamu>Zhikonggaxia>lianmubai>Jiangreejiu>Longzihei. 展开更多
关键词 Tibetan hulless barley process quality comprehensive evaluation factor analysis
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Analysis on the Trend and Change Process of Preschool Education Supply System in China
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作者 Luo Ruofei 《学术界》 CSSCI 北大核心 2013年第11期293-299,共7页
In order to put forward countermeasures and suggestions of reform and innovation on the supply system of preschool education in China,the current change process of China’s preschool education supply system is analyze... In order to put forward countermeasures and suggestions of reform and innovation on the supply system of preschool education in China,the current change process of China’s preschool education supply system is analyzed using the historical analysis method.It is believed that there are still some outstanding problems in the supply system of the preschool education in China at present.According to the theory of supply and demand balance of economics and institutional change theory of new institutional economics,the future trend of China’s preschool education supply system is also analyzed. 展开更多
关键词 学前教育 供给系统 发展趋势 中国 新制度经济学 供应系统 电流变化 供需平衡
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基于MS Analysis Services的OLAP分析系统模型设计及应用 被引量:2
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作者 杨彬彬 郑晓薇 《计算机应用与软件》 CSCD 北大核心 2007年第8期216-218,共3页
首先对OLAP和MS Analysis Services技术进行了讨论,然后提出了一种基于MS Analysis Services的OLAP分析系统模型设计,模型具有通用性、实用性和开放性。最后给出了运用此模型构建的OLAP分析系统实例,阐述了系统开发的步骤。实践证明运... 首先对OLAP和MS Analysis Services技术进行了讨论,然后提出了一种基于MS Analysis Services的OLAP分析系统模型设计,模型具有通用性、实用性和开放性。最后给出了运用此模型构建的OLAP分析系统实例,阐述了系统开发的步骤。实践证明运用提出的模型构建OLAP分析系统,实现了良好的分析决策功能。 展开更多
关键词 数据仓库 联机分析处理 MS analysis SERVICES ADOMD
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Safety analysis of wheel brake system based on STAMP/STPA and Monte Carlo simulation 被引量:8
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作者 HU Jianbo ZHENG Lei XU Shukui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第6期1327-1339,共13页
The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with ... The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing. 展开更多
关键词 safety analysis landing taxiing system-theoretic accident model and processes(STAMP) model and system theoretic process analysis(STPA)(STAMP/STPA) feedback control loop Monte Carlo simulation
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Dynamic analysis of elastic screen surface with multiple attached substructures and experimental validation 被引量:2
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作者 王宏 刘初升 +2 位作者 彭利平 蒋小伟 冀连权 《Journal of Central South University》 SCIE EI CAS 2012年第10期2910-2917,共8页
A feasible method to improve the reliability and processing efficiency of large vibrating screen via the application of an elastic screen surface with multiple attached substructures (ESSMAS) was proposed. In the ES... A feasible method to improve the reliability and processing efficiency of large vibrating screen via the application of an elastic screen surface with multiple attached substructures (ESSMAS) was proposed. In the ESSMAS, every screen rod, with ends embedded into elastomer, is coupled to the main screen structure in a relatively flexible manner. The theoretical analysis was conducted, which consists of establishing dynamic model promoted from the fuzzy structure theory as well as calculating for the equivalent stiffness of each attached structure. According to the numerical simulation using the NEWMARK-fl integration method, this assembling pattern significantly leads to the screen surface/rod having larger vibration intensity than that of the corresponding position on screen structure, which specifically, with an averaged acceleration amplitude increasing ratio of 11.37% in theoretical analysis and 20.27% in experimental test. The experimental results, within a tolerant error, also confirm the established model and demonstrate the feasibility of ESSMAS. 展开更多
关键词 mineral processing vibrating screen elastic screen surface attached substructures dynamic analysis reliability processing efficiency
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Reliability Analysis of Some Typical Repairable Systems with Arbitrary Repair-Time Distribution
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作者 Wang Jing and Yang DeliInst. of Systems Eng., Dalian Univ. of Tech., Dalian 116023, China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1992年第4期61-72,共12页
In this paper, reliability of some typical non-Markov repairable systems, including series systems, m-out-of- n or majority vote systems, and n : m cross-strapping standby redundant systems with general repair-time di... In this paper, reliability of some typical non-Markov repairable systems, including series systems, m-out-of- n or majority vote systems, and n : m cross-strapping standby redundant systems with general repair-time distribution, are studied by applying the generalized Markov renewal process (GMRP). The stochastic behavior of the typical systems is analyzed here. Formulas for mean time to first system failure, MTBF, MTTR, and availability are then developed. 展开更多
关键词 Repairable systems Reliability analysis Markov processes.
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Efficiency analysis of trilateral-cycle power systems for waste heat recovery-to-power generation
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作者 Habeeb A.AJIMOTOKAN 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第12期3160-3170,共11页
Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the pro... Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the proposed trilateral-cycle(TLC) power system exhibits high thermodynamic efficiency during heat recovery-to-power from low-to-medium temperature heat sources.The TLCs are proposed and analysed using n-pentane as working fluid for waste heat recovery-to-power generation from low-grade heat source to evaluate the thermodynamic efficiency of the cycles.Four different single stage TLC configurations with distinct working principles are modelled thermodynamically using engineering equation solver.Based on the thermodynamic framework,thermodynamic performance simulation and efficiency analysis of the cycles as well as the exergy efficiencies of the heating and condensing processes are carried out and compared in their efficiency.The results show that the simple TLC,recuperated TLC,reheat TLC and regenerative TLC operating at subcritical conditions with cycle high temperature of 473 K can attain thermal efficiencies of 21.97%,23.91%,22.07% and 22.9%,respectively.The recuperated TLC attains the highest thermodynamic efficiency at the cycle high temperature because of its lowest exergy destruction rates in the heat exchanger and condenser.The efficiency analysis carried out would assist in guiding thermodynamic process development and thermal integration of the proposed cycles. 展开更多
关键词 trilateral cycle waste heat recovery-to-power generation thermodynamic performance simulation efficiency analysis process development and integration
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Assessment Method for the Reliability of Power Transformer Based on Fault-tree Analysis 被引量:15
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作者 WANG You-yuan ZHOU Jing-jing CHEN Wei-gen DU Lin CHEN Ren-gang 《高电压技术》 EI CAS CSCD 北大核心 2009年第3期514-520,共7页
关键词 电力变压器 供电系统 故障树分析 失效模式
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Extraction of yarn positional information from three-dimensional CT image of textile fabric using a yarn model for its structure analysis 被引量:1
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作者 Toshihiro Shinohara Jun-ya Takayama +1 位作者 Shinji Ohyama Akira Kobayashi 《仪器仪表学报》 EI CAS CSCD 北大核心 2008年第8期1569-1576,共8页
This paper proposes a novel method for analyzing a textile fabric structure to extract positional information regarding each yarn using three-dimensional X-ray computed tomography(3D CT) image.Positional relationship ... This paper proposes a novel method for analyzing a textile fabric structure to extract positional information regarding each yarn using three-dimensional X-ray computed tomography(3D CT) image.Positional relationship among the yarns can be reconstructed using the extracted yarn positional information.In this paper,a sequence of points on the center line of each yarn of the sample is defined as the yarn positional information,since the sequence can be regarded as the representative position of the yarn.The sequence is extracted by tracing the yarn.The yarn is traced by estimating the yarn center and direction and correlating the yarn part of the 3D CT image with a 3D yarn model,which is moved along the estimated yarn direction.The trajectory of the center of the yarn model corresponds to the positional information of the yarn.The application of the proposed method is shown by experimentally applying the proposed method to a 3D CT image of a double-layered woven fabric.Furthermore,the experimental results for a plain knitted fabric show that this method can be applied to even knitted fabrics. 展开更多
关键词 纺织品 CT影像 分析方法 物理结构
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醋白芍炮制工艺优化
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作者 刘静静 石典花 +2 位作者 田崇娅 戴衍朋 辛义周 《中成药》 北大核心 2025年第4期1111-1116,共6页
目的优化醋白芍炮制工艺。方法采用电子鼻测定不同炒制程度醋白芍气味值,Pearson相关性分析对电子鼻各传感器响应值与炮制品内在指标成分含量进行相关性分析,探索气味值与内在质量的相关性。以炒制温度、炒制时间、闷润时间为影响因素,... 目的优化醋白芍炮制工艺。方法采用电子鼻测定不同炒制程度醋白芍气味值,Pearson相关性分析对电子鼻各传感器响应值与炮制品内在指标成分含量进行相关性分析,探索气味值与内在质量的相关性。以炒制温度、炒制时间、闷润时间为影响因素,气味值及芍药苷、芍药内酯苷、水溶性浸出物含量的综合评分为评价指标,正交试验优化炮制工艺。结果电子鼻差异感应响应值与米醋相同。最佳条件为净白芍用醋闷润30~60 min后,在180℃下炒制15 min(每100 g饮片用20 g米醋),芍药苷、芍药内酯苷、水溶性浸出物含量分别为2.74%、0.60%、30.09%。结论电子鼻可实现不同炮制程度醋白芍气味的客观判断,能用于其他中药炮制工艺的优化。 展开更多
关键词 醋白芍 炮制工艺 电子鼻 Pearson相关性分析 正交试验
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基于知识封装的船舶阻力性能虚拟试验流程研发及其应用效果分析
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作者 朱锋 李胜忠 +2 位作者 鲍家乐 梁川 赵峰 《船舶力学》 北大核心 2025年第1期23-30,共8页
本文依托“属性细分,知识封装”的原则,开展基于RANS方程的船舶阻力性能虚拟试验应用流程研究,通过封装虚拟试验专家知识,建立船舶阻力性能虚拟试验应用流程。该流程对标物理水池模型试验流程,用户仅需输入试验对象几何曲面以及主尺度参... 本文依托“属性细分,知识封装”的原则,开展基于RANS方程的船舶阻力性能虚拟试验应用流程研究,通过封装虚拟试验专家知识,建立船舶阻力性能虚拟试验应用流程。该流程对标物理水池模型试验流程,用户仅需输入试验对象几何曲面以及主尺度参数,即可开展阻力性能精细预报工作。经大子样验证,该流程预报精度高、效果好,与传统CFD阻力数值计算相比,可大幅提高船舶阻力性能的评估效率,缩短船舶性能研发周期,大幅降低应用门槛。 展开更多
关键词 阻力性能 专家知识 应用流程 效益分析
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窟野河流域次降雨事件下水沙变化特征及其输移过程
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作者 杨晨 佘冬立 黄萱 《水土保持研究》 北大核心 2025年第2期52-60,共9页
[目的]深入分析黄土高原粗沙区流域次降雨事件尺度下水沙动态变化特征及其输移过程,为黄土高原粗沙区流域的水沙管理和调控提供重要科学依据。[方法]以黄土高原中游粗沙多沙区窟野河流域为对象,收集2006—2019年间的160场次降雨事件水... [目的]深入分析黄土高原粗沙区流域次降雨事件尺度下水沙动态变化特征及其输移过程,为黄土高原粗沙区流域的水沙管理和调控提供重要科学依据。[方法]以黄土高原中游粗沙多沙区窟野河流域为对象,收集2006—2019年间的160场次降雨事件水沙数据。通过运用方差分析、水沙关系曲线、滞后分析等方法,比较位于窟野河及其子流域次降雨事件下产流输沙特征,构建了各流域次降雨事件尺度下水沙关系曲线,分析了水沙滞后关系及滞后指数的空间差异,以揭示次降雨尺度下窟野河流域的水沙输移过程。[结果](1)4个流域径流相关参数无显著差异,但泥沙相关参数差异显著;(2)位于窟野河上游东部的新庙流域水沙相关性强,表征外界人为干扰的参数(a)最大,位于上游西部的王道恒塔流域泥沙浓度低,水沙相关性弱,表征河流本身输沙能力的参数(b)最大;(3)新庙、王道恒塔和温家川3个流域的主要滞后模式为逆时针型,泥沙来源于上游区域,且高含沙降雨事件的滞后系数(HI)平均值多为负;而神木流域的主要滞后模式为“8”字型,指示泥沙来源相对接近流域出口,且高含沙降雨事件的HI平均值多为正。[结论]窟野河嵌套流域次降雨事件尺度下水沙变化空间差异显著,泥沙输移过程复杂,不同子流域滞后模式揭示了泥沙来源和输移机制的空间异质性。 展开更多
关键词 次降雨事件尺度 输移过程 水沙关系 滞后分析
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基于深度模型的海水透明度遥感数据智能分析
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作者 朱海荣 蔡鹏 +2 位作者 陈新东 宗敬文 赵文仓 《兵器装备工程学报》 北大核心 2025年第1期295-298,共4页
为了减少海水遥感数据模态多样对海水透明度遥感反演的影响,通过在对水色卫星遥感数据预处理标注,完成数据的交叉校准、质量控制,开展海水透明度智能分析,将不完全、多模态海水透明度遥感数据投影到统一共享特征子空间,通过对数据自适... 为了减少海水遥感数据模态多样对海水透明度遥感反演的影响,通过在对水色卫星遥感数据预处理标注,完成数据的交叉校准、质量控制,开展海水透明度智能分析,将不完全、多模态海水透明度遥感数据投影到统一共享特征子空间,通过对数据自适应检测分析、智能化处理,建立海水透明度遥感数据智能分析模型。并利用模型对观测点海水透明度开展反演分析,验证了深度模型具有良好的预测能力,实现少标注下遥感透明度数据的智能分析。 展开更多
关键词 海水透明度 自适应检测 遥感数据 图像处理 分析
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快艇螺旋桨线谱特性分析及检测
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作者 陈新华 李嶷 +2 位作者 郑恩明 方华 杨鹤 《哈尔滨工程大学学报》 北大核心 2025年第4期660-666,共7页
为了获得目标声纹特征,本文对快艇的湖上试验数据进行分析。利用低频分析记录图研究实际工作中目标线谱在图中的表现,同时针对快艇工况稳定和转向时的2种情况,研究快艇螺旋桨各时刻的线谱特性。采用长时间数据和短时间数据做快速傅里叶... 为了获得目标声纹特征,本文对快艇的湖上试验数据进行分析。利用低频分析记录图研究实际工作中目标线谱在图中的表现,同时针对快艇工况稳定和转向时的2种情况,研究快艇螺旋桨各时刻的线谱特性。采用长时间数据和短时间数据做快速傅里叶变换的方法对线谱进行检测,验证不同试验场景下这2种方法检测线谱的性能优劣,提出对长时间数据做快速傅里叶变换的工程实现方法。研究表明:目标线谱会随着目标工况的变化而发生漂移;低频分析记录图中线谱的基频和谐波信号强度具有随机性;在目标工况稳定或变化剧烈时宜分别采用长时间或短时间傅里叶变换进行线谱检测。本文为目标检测和识别提供理论和实践指导。 展开更多
关键词 信号处理 频谱分析 信号检测 水下声信号 螺旋桨 舰船噪声 线谱 低频分析记录图
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