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基于病菌孢子捕捉和real-time PCR技术的田间空气中小麦白粉病菌孢子动态监测及病情估计模型研究
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作者 王奥霖 商昭月 +8 位作者 张美惠 王贵 胡小平 徐飞 孙振宇 曹世勤 刘伟 范洁茹 周益林 《植物保护》 CAS CSCD 北大核心 2024年第2期49-56,72,共9页
利用Burkard定容式孢子捕捉器结合real-time PCR定量技术,分别对种植高抗、中感和高感白粉病小麦品种的田间空气中白粉病菌分生孢子浓度进行监测,结果表明,real-time PCR定量与传统的显微观察计数两种方法测得的孢子浓度呈显著正相关(P... 利用Burkard定容式孢子捕捉器结合real-time PCR定量技术,分别对种植高抗、中感和高感白粉病小麦品种的田间空气中白粉病菌分生孢子浓度进行监测,结果表明,real-time PCR定量与传统的显微观察计数两种方法测得的孢子浓度呈显著正相关(P≤0.01),且两种病菌孢子计数方法在同一抗性品种上监测到的孢子浓度动态相近。此外,两种方法测得的孢子浓度与各气象因子的相关性分析结果一致,空气中的白粉病菌孢子浓度主要与空气相对湿度显著正相关。在此基础上,利用两种方法测定的田间空气中白粉病菌孢子浓度分别建立了基于累积孢子浓度的田间病情估计模型。分析发现,基于两种孢子浓度测定方法建立的病情估计模型间无显著性差异,表明real-time PCR定量技术测定的孢子浓度在构建白粉病病情估计模型上具有一定可行性。该结果为real-time PCR定量技术与病菌孢子捕捉技术相结合用于小麦白粉病的监测和预测提供理论依据。 展开更多
关键词 小麦白粉病 病菌孢子捕捉 实时荧光定量PCR 病原菌监测 病情估计模型
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An Effective Prediction Method for Supporting Decision Making in Real Estate Area Selection
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作者 Haoying Jin Song Yang Mingzhi Zhao 《Journal of Computer and Communications》 2024年第7期105-119,共15页
Real estate has been a dominant industry in many countries. One problem for real estate companies is determining the most valuable area before starting a new project. Previous studies on this issue mainly focused on m... Real estate has been a dominant industry in many countries. One problem for real estate companies is determining the most valuable area before starting a new project. Previous studies on this issue mainly focused on market needs and economic prospects, ignoring the impact of natural disasters. We observe that natural disasters are important for real estate area selection because they will introduce considerable losses to real estate enterprises. Following this observation, we first develop a self-defined new indicator named Average Loss Ratio to predict the losses caused by natural disasters in an area. Then, we adopt the existing ARIMA model to predict the Average Loss Ratio of an area. After that, we propose to integrate the TOPSIS model and the Grey Prediction Model to rank the recommendation levels for candidate areas, thereby assisting real estate companies in their decision-making process. We conduct experiments on real datasets to validate our proposal, and the results suggest the effectiveness of the proposed method. 展开更多
关键词 real Estate Natural Disaster Decision Making Prediction model
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Modeling Real Objects for Kansei-based Shape Retrieval 被引量:2
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作者 Yukihiro Koda Ichi Kanaya Kosuke Sato 《International Journal of Automation and computing》 EI 2007年第1期14-17,共4页
A large number of 3D models are created on computers and available for networks. Some content-based retrieval technologies are indispensable to find out particular data from such anonymous datasets. Though several sha... A large number of 3D models are created on computers and available for networks. Some content-based retrieval technologies are indispensable to find out particular data from such anonymous datasets. Though several shape retrieval technologies have been developed, little attention has been given to the points on human's sense and impression (as known as Kansei) in the conventional techniques, In this paper, the authors propose a novel method of shape retrieval based on shape impression of human's Kansei. The key to the method is the Gaussian curvature distribution from 3D models as features for shape retrieval. Then it classifies the 3D models by extracted feature and measures similarity among models in storage. 展开更多
关键词 Shape retrieval Kansei engineering modeling of real object.
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Investment in deepwater oil and gas exploration projects:a multi-factor analysis with a real options model 被引量:5
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作者 Xin-Hua Qiu Zhen Wang Qing Xue 《Petroleum Science》 SCIE CAS CSCD 2015年第3期525-533,共9页
Deepwater oil and gas projects embody high risks from geology and engineering aspects, which exert substantial influence on project valuation. But the uncer- tainties may be converted to additional value to the projec... Deepwater oil and gas projects embody high risks from geology and engineering aspects, which exert substantial influence on project valuation. But the uncer- tainties may be converted to additional value to the projects in the case of flexible management. Given the flexibility of project management, this paper extends the classical real options model to a multi-factor model which contains oil price, geology, and engineering uncertainties. It then gives an application example of the new model to evaluate deepwater oil and gas projects with a numerical analytical method. Compared with other methods and models, this multi-factor real options model contains more project information. It reflects the potential value deriving not only from oil price variation but also from geology and engi- neering uncertainties, which provides more accurate and reliable valuation information for decision makers. 展开更多
关键词 Investment decision - real options Multi-factor model Option pricing - Deepwater oil and gas
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基于Simulink Real-Time的汽车空调半实物仿真试验系统研发 被引量:1
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作者 姚栋伟 吴晓虎 +4 位作者 卢鑫威 张永光 付忠亮 黄忠毅 吴锋 《国外电子测量技术》 北大核心 2023年第9期114-121,共8页
针对多样化汽车空调电子零部件的高效、低成本总成级测试需求,研究基于一汽大众速腾1.6 L车型原型,设计了基于Simulink Real-Time的汽车空调半实物仿真试验系统。该系统集成了真实的汽车空调总成、制冷循环以及包含宿主机和目标机的双... 针对多样化汽车空调电子零部件的高效、低成本总成级测试需求,研究基于一汽大众速腾1.6 L车型原型,设计了基于Simulink Real-Time的汽车空调半实物仿真试验系统。该系统集成了真实的汽车空调总成、制冷循环以及包含宿主机和目标机的双机实时仿真系统,用于开发和运行台架监控和空调控制模型,为汽车空调电子零部件提供半实物仿真测试环境。通过系统集成及功能验证,结果表明,汽车空调半实物仿真试验系统能够实现汽车空调基本控制功能,同时在不同工况下实现乘员舱温度控制的稳定性,稳态误差控制在±1℃以内。此外,该系统还具备灵活调整空调运行工况和状态的能力,为汽车空调电子零部件提供了高效、低成本的半实物仿真测试环境。 展开更多
关键词 Simulink real-Time 汽车空调 半实物仿真 仿真模型 试验系统
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On modeling approach for embedded real-time software simulation testing 被引量:6
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作者 Yin Yongfeng Liu Bin Zhong Deming Jiang Tongmin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第2期420-426,共7页
Modeling technology has been introduced into software testing field. However, how to carry through the testing modeling effectively is still a difficulty. Based on combination of simulation modeling technology and emb... Modeling technology has been introduced into software testing field. However, how to carry through the testing modeling effectively is still a difficulty. Based on combination of simulation modeling technology and embedded real-time software testing method, the process of simulation testing modeling is studied first. And then, the supporting environment of simulation testing modeling is put forward. Furthermore, an approach of embedded real-time software simulation testing modeling including modeling of cross-linked equipments of system under testing (SUT), test case, testing scheduling, and testing system service is brought forward. Finally, the formalized description and execution system of testing models are given, with which we can realize real-time, closed loop, mad automated system testing for embedded real-time software. 展开更多
关键词 embedded real-time software software testing testing modeling SIMULATION
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BRAIN INJURY BIOMECHANICS IN REAL WORLD VEHICLE ACCIDENT USING MATHEMATICAL MODELS 被引量:10
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作者 YANG Jikuang XU Wei OTTE Dietmar 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2008年第4期81-86,共6页
This paper aims at investigating brain injury mechanisms and predicting head injuries in real world accidents. For this purpose, a 3D human head finite element model (HBM-head) was developed based on head-brain anat... This paper aims at investigating brain injury mechanisms and predicting head injuries in real world accidents. For this purpose, a 3D human head finite element model (HBM-head) was developed based on head-brain anatomy. The HBM head model was validated with two experimental tests. Then the head finite element(FE) model and a multi-body system (MBS) model were used to carry out reconstructions of real world vehicle-pedestrian accidents and brain injuries. The MBS models were used for calculating the head impact conditions in vehicle impacts. The HBM-head model was used for calculating the injury related physical parameters, such as intracranial pressure, stress, and strain. The calculated intracranial pressure and strain distribution were correlated with the injury outcomes observed from accidents. It is shown that this model can predict the intracranial biomechanical response and calculate the injury related physical parameters. The head FE model has good biofidelity and will be a valuable tool for the study of injury mechanisms and the tolerance level of the brain. 展开更多
关键词 Skull-brain FE model Head injury real-world vehicle accident
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Experimental Model and Analytic Solution for Real-time Observation of Vehicle's Additional Steer Angle 被引量:3
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作者 ZHANG Xiaolong LI Liang +2 位作者 PAN Deng CAO Chengmao SONG Jian 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第2期340-347,共8页
The current research of real-time observation for vehicle roll steer angle and compliance steer angle(both of them comprehensively referred as the additional steer angle in this paper) mainly employs the linear vehi... The current research of real-time observation for vehicle roll steer angle and compliance steer angle(both of them comprehensively referred as the additional steer angle in this paper) mainly employs the linear vehicle dynamic model, in which only the lateral acceleration of vehicle body is considered. The observation accuracy resorting to this method cannot meet the requirements of vehicle real-time stability control, especially under extreme driving conditions. The paper explores the solution resorting to experimental method. Firstly, a multi-body dynamic model of a passenger car is built based on the ADAMS/Car software, whose dynamic accuracy is verified by the same vehicle's roadway test data of steady static circular test. Based on this simulation platform, several influencing factors of additional steer angle under different driving conditions are quantitatively analyzed. Then ε-SVR algorithm is employed to build the additional steer angle prediction model, whose input vectors mainly include the sensor information of standard electronic stability control system(ESC). The method of typical slalom tests and FMVSS 126 tests are adopted to make simulation, train model and test model's generalization performance. The test result shows that the influence of lateral acceleration on additional steer angle is maximal (the magnitude up to 1°), followed by the longitudinal acceleration-deceleration and the road wave amplitude (the magnitude up to 0.3°). Moreover, both the prediction accuracy and the calculation real-time of the model can meet the control requirements of ESC This research expands the accurate observation methods of the additional steer angle under extreme driving conditions. 展开更多
关键词 VEHICLE ADAMS model additional steer SVM real-time observation
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基于DP-Modeler的实景三维校园精细化模型构建 被引量:3
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作者 郭昕怡 刘军 +1 位作者 陈毓洁 胡泽坤 《山西建筑》 2023年第24期165-168,193,共5页
无人机倾斜摄影测量自动化三维建模技术具备高效率、低成本和高精度的特点,已经得到了广泛应用。为了进一步提升实景三维模型的质量,以防灾科技学院校园为例,在实景三维模型自动化构建基础上,利用DP-Modeler完成了三维场景的修饰和建筑... 无人机倾斜摄影测量自动化三维建模技术具备高效率、低成本和高精度的特点,已经得到了广泛应用。为了进一步提升实景三维模型的质量,以防灾科技学院校园为例,在实景三维模型自动化构建基础上,利用DP-Modeler完成了三维场景的修饰和建筑物精细化单体建模。结果表明:DP-Modeler软件直接在倾斜三维模型上交互式单体化建模,具有自动化程度高、简单易用等特点,能够有效提升三维建模的效率,所构建的实景三维模型能够客观真实地反映校园场景。 展开更多
关键词 无人机倾斜摄影 实景三维模型 DP-modeler 单体化
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A Novel Approach to Study Regional Ionospheric Variations Using a Real-Time TEC Model
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作者 S. C. Chakravarty 《Positioning》 2014年第1期1-11,共11页
Since IGY (International Geophysical Year), through coordinated global observations, ionospheric research has been carried out by many countries. This effort primarily helped in the design and operation of HF radio wa... Since IGY (International Geophysical Year), through coordinated global observations, ionospheric research has been carried out by many countries. This effort primarily helped in the design and operation of HF radio wave communication systems. The Indian region covers a highly variable part of the equatorial electrojet and EIA (Equatorial Ionisation Anomaly) phenomena making its predictability difficult. With the advent of satellite communication and navigation, the need for accurate ionospheric TEC (Total Electron Content) models at global and regional scales has been stressed. The GAGAN (GPS Aided Geo Augmented Navigation) project jointly undertaken by the Indian Space Research Organisation (ISRO) and the Airport Authority of India (AAI) aims at effectively utilising the Global Navigational Satellite System (GNSS) to determine position coordinates accurately for aircraft precision landing applications. For this purpose the range errors are estimated by using a ground network of TEC stations spread over Indian region. The near simultaneous data collected from these dual frequency GPS stations can be used to generate the geo-referenced TEC values for various applications. The author has developed necessary algorithm and associated computer programmes for a real-time vertical TEC (VTEC) model based on TEC data collected from the GAGAN ground based network stations. The model has been tested and sample results presented here show that it adequately provides for the latitudinal resolution of 1° for the entire longitude span and also for two longitude blocks (73 - 83 & 83 - 93°E) separately. Cubic spline and bilinear interpolation techniques are used for filling up temporal and spatial data gaps. The model provides tabulated output of hourly average VTEC data with latitude for ready use, as well as graphical displays of VTEC maps and contours for monitoring purpose. The real-time model and its extensions are also being used for detailed scientific studies;examples of these show small day to day variability of VTEC without any change in solar activity and indication of the change in the shape of the VTEC diurnal curve with season. The present model will be used for further studies to derive the monthly average variation of the diurnal pattern and the relationship between VTEC peak amplitudes with changes in solar activity. The new information generated can be fed back to improve the real-time model so that eventually the dependence of such models on ground based network stations data can be minimised. 展开更多
关键词 GPS real Time VTEC model GAGAN Low LATITUDE TEC
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Application of PPC Model Based on RAGA in Real Estate Investment Decision-Making
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作者 Shujing ZHOU Fei WANG Yancang LI 《Engineering(科研)》 2009年第2期106-110,共5页
According to the size of the projector function to evaluate the merits of the program, Projection Pursuit method is applied to real estate investment decision-making by using the real coding based on Accelerating Gene... According to the size of the projector function to evaluate the merits of the program, Projection Pursuit method is applied to real estate investment decision-making by using the real coding based on Accelerating Genetic Algorithm (RAGA) to optimize the Projection Pursuit Classification (PPC) process and a wide range of indicators value was projected linearly. The results are reasonable and verified with an example. At the same time, the subjective of the target weight can be avoided. It provides decision-makers with comprehensive information on all the indicators of new ideas and new 展开更多
关键词 real ESTATE PPC model INVESTMENT DECISION-MAKING Accelerating GENETIC Algorithm
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THE DLSTRIBOTED MCU MODEL FOR SYNCHRONOUS REAL-TIME TELETEACHING
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作者 刘均 李人厚 郑庆华 《Journal of Pharmaceutical Analysis》 SCIE CAS 2004年第1期22-25,共4页
Aiming at issues on multimedia communication in synchronous real-time teleteaching (SRT) systems over IP network, a 4-tuple structural mode of multimedia communication is proposed in the paper, and an SRT-oriented dis... Aiming at issues on multimedia communication in synchronous real-time teleteaching (SRT) systems over IP network, a 4-tuple structural mode of multimedia communication is proposed in the paper, and an SRT-oriented distributed MCU model is built according to the mode. Moreover, the mechanism of multicast communication across subnets is discussed. The distributed MCU model has been applied successfully in our interactive synchronous real-time telesteaching system RealClass and has shown good extendibility in operation. 展开更多
关键词 synchronous real-time teleteaching distributed MCU model MULTICAST
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Formal Modeling and Analysis of AADL Threads in Real Time Maude
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作者 F. Belala M. Benammar +1 位作者 K. Barkaoui A. Hicheur 《Journal of Software Engineering and Applications》 2012年第12期187-192,共6页
This paper presents, without altering the AADL meta-model, a formal description of static and behavioral aspects of the AADL thread component. This active and concurrent applicative component of AADL poses many challe... This paper presents, without altering the AADL meta-model, a formal description of static and behavioral aspects of the AADL thread component. This active and concurrent applicative component of AADL poses many challenges to its formalization and analysis including instantaneous and/or delayed communications, concurrent tasks and time-dependent features, and the need to analyze correctness. This formalization, based on real-time object-oriented theories, allows not only a precise description of the semantics of threads composition with respect to their timing requirements but also makes possible the formal verification of behavioral properties. 展开更多
关键词 Architecture Description Language (ADL) AADL thread component real Time MAUDE model CHECKING
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城市实景模型结构化线面特征重构方法 被引量:1
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作者 梅熙 王义 +1 位作者 曲英杰 邓非 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第1期130-136,共7页
为了改善城市实景模型边缘模糊,提出了一种曲率引导的结构化线面特征重构方法。根据曲率特征将网格分割为平面、可展凹、可展凸以及不可展曲面4类,在平面分割结果内提取平面,在可展凹和可展凸分割结果内提取直线,对过度弯曲的不可展区... 为了改善城市实景模型边缘模糊,提出了一种曲率引导的结构化线面特征重构方法。根据曲率特征将网格分割为平面、可展凹、可展凸以及不可展曲面4类,在平面分割结果内提取平面,在可展凹和可展凸分割结果内提取直线,对过度弯曲的不可展区域进行保留,最终形成包含几何特征的复合网格模型。结果表明,结合曲率信息预先设置几何特征的潜在范围,使得结构化线面特征更可靠,同时保证城市实景中复杂的树结构不被错误地提取为平面。 展开更多
关键词 实景三维模型 三维重建 网格 线特征 面特征 马尔科夫随机场(MRF) 简化
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面向水库型小流域的多源水利三维建模方法研究 被引量:1
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作者 胡金龙 胡宜娜 +2 位作者 钱进 朱海波 胡文斌 《水利信息化》 2024年第1期41-45,共5页
针对大型河道三维可视化建模中采用激光雷达、声呐等传感器获取水下地形建模方式操作复杂且成本较高的缺陷,在利用基础测绘成果构建实景地形模型的基础上,采用多源三维模型融合方法对月塘水库小流域进行实景建模。首先采用倾斜摄影三维... 针对大型河道三维可视化建模中采用激光雷达、声呐等传感器获取水下地形建模方式操作复杂且成本较高的缺陷,在利用基础测绘成果构建实景地形模型的基础上,采用多源三维模型融合方法对月塘水库小流域进行实景建模。首先采用倾斜摄影三维建模技术对重点水利工程进行实景建模,并利用专业建模软件对重要控制单元进行构件级建模;然后利用已有河道断面数据结合河流面状矢量数据,实现流域内胥浦河河道实景三维建模;最后通过人机交互方式对多源实景模型进行微调与相互印证,实现月塘水库小流域多源三维模型精准融合构建。研究成果可为河道型水库的预报调度与洪水风险分析提供可视化模型基础与决策支撑。 展开更多
关键词 实景三维建模 多源模型融合 倾斜摄影 数据生态 水库型小流域
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Model-based framework for multi-axial real-time hybrid simulation testing 被引量:4
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作者 Gaston A.Fermandois Billie F.Spencer,Jr. 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2017年第4期671-691,共21页
Real-time hybrid simulation is an efficient and cost-effective dynamic testing technique for performance evaluation of structural systems subjected to earthquake loading with rate-dependent behavior. A loading assembl... Real-time hybrid simulation is an efficient and cost-effective dynamic testing technique for performance evaluation of structural systems subjected to earthquake loading with rate-dependent behavior. A loading assembly with multiple actuators is required to impose realistic boundary conditions on physical specimens. However, such a testing system is expected to exhibit significant dynamic coupling of the actuators and suffer from time lags that are associated with the dynamics of the servo-hydraulic system, as well as control-structure interaction (CSI). One approach to reducing experimental errors considers a multi-input, multi-output (MIMO) controller design, yielding accurate reference tracking and noise rejection. In this paper, a framework for multi-axial real-time hybrid simulation (maRTHS) testing is presented. The methodology employs a real-time feedback-feedforward controller for multiple actuators commanded in Cartesian coordinates. Kinematic transformations between actuator space and Cartesian space are derived for all six-degrees-of- freedom of the moving platform. Then, a frequency domain identification technique is used to develop an accurate MIMO transfer function of the system. Further, a Cartesian-domain model-based feedforward-feedback controller is implemented for time lag compensation and to increase the robustness of the reference tracking for given model uncertainty. The framework is implemented using the 1/5th-scale Load and Boundary Condition Box (LBCB) located at the University of Illinois at Urbana- Champaign. To demonstrate the efficacy of the proposed methodology, a single-story frame subjected to earthquake loading is tested. One of the columns in the fraane is represented physically in the laboratory as a cantilevered steel column. For real- time execution, the numerical substructure, kinematic transformations, and controllers are implemented on a digital signal processor. Results show excellent performance of the maRTHS framework when six-degrees-of-freedom are controUed at the interface between substructures. 展开更多
关键词 real-time hybrid simulation multiple actuators dynamic coupling kinematic transformations model-basedcompensation
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高压氢气泄漏过程中气体参数计算的新方法
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作者 朱建鲁 王赛磊 +2 位作者 周慧 王国聪 李玉星 《安全与环境学报》 CAS CSCD 北大核心 2024年第1期236-243,共8页
基于气体等熵喷射过程和绝热变化过程分析氢气泄漏的热力学过程,建立理想气体状态方程、Abel-Noble状态方程和基于NIST(National Institute of Standards and Technology)的真实气体状态方程的计算模型,利用MATLAB对稳态/非稳态泄漏过... 基于气体等熵喷射过程和绝热变化过程分析氢气泄漏的热力学过程,建立理想气体状态方程、Abel-Noble状态方程和基于NIST(National Institute of Standards and Technology)的真实气体状态方程的计算模型,利用MATLAB对稳态/非稳态泄漏过程进行计算。结果显示,建立的稳态泄漏模型能够精确计算泄漏口处的相关参数,在保证计算精度的前提下与数值模拟相比,误差可以忽略不计;非稳态泄漏模型中,与基于理想气体状态方程和Abel-Noble状态方程相比,基于NIST的真实气体状态方程误差更小;非稳态泄漏过程中,罐内气体温度高于理论预测值,泄漏质量流量小于理论预测值。真实气体模型在一定程度上体现了热力学模型的局限性,但与数值模拟等计算方法相比,该模型计算更加快捷精准,对实际气体泄漏事故的预测具有理论指导意义。 展开更多
关键词 安全工程 氢气泄漏 理想气体状态模型 Abel-Noble状态方程 真实气体模型 MATLAB
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基于1dCNN-LSTM量化单体异常性的动力电池故障诊断方法
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作者 陈吉清 冯雨佳 +1 位作者 兰凤崇 王平 《汽车工程》 EI CSCD 北大核心 2024年第7期1177-1188,共12页
准确的动力电池单体性能评估对保障动力电池安全具有重要意义。目前基于数据驱动的电池故障诊断算法,大多对各单体电池进行相互比较,根据各单体电压等特征参数之间的差异,使用分类算法将离群单体认定为故障单体。然而当动力电池包内有... 准确的动力电池单体性能评估对保障动力电池安全具有重要意义。目前基于数据驱动的电池故障诊断算法,大多对各单体电池进行相互比较,根据各单体电压等特征参数之间的差异,使用分类算法将离群单体认定为故障单体。然而当动力电池包内有多个异常表现相似的电池单体,或所有单体性能整体恶化时,难以区分甚至没有显著离群的个别单体,相互比较策略的应用范围受到限制。本文提出了一种基于1dCNN-LSTM量化单体异常性的动力电池故障诊断方法,结合车辆运动状态、驱动系统状态及动力电池电信号3类特征,建立1dCNN-LSTM融合模型估计理想状态下的单体实时电压参考值,根据各单体电压实测值与参考值之间的差异,量化各单体异常性。结合实际案例表明,对于因单体故障导致热失控的案例,本方法可以提前7日识别故障单体相比其他单体的明显异常,且可以在距离事故发生1年前甚至更早的放电片段中发现潜在风险;针对无明显单体不一致的整体恶化案例,可以实现事故发生前7日内的整体性能恶化过程跟踪。 展开更多
关键词 动力电池 故障诊断 单体不一致性 融合模型 实时电压估计
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Three-Dimensional Nonlinear Dynamic Model and Macro Control of Real Estate
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作者 Dan Ma Shengwu Zhou Haojin Lv 《Intelligent Information Management》 2010年第5期325-328,共4页
In this paper, according to economics of real estate and macro-control theory, combine with the characteristics of the real estate market, macro-control of the real estate market is studied. After giving the dynamic m... In this paper, according to economics of real estate and macro-control theory, combine with the characteristics of the real estate market, macro-control of the real estate market is studied. After giving the dynamic model of three-dimensional nonlinear differential equations based on the total number of houses on the real estate business, the government’s averages housing investment funds and the standard price, systematically established the stability conditions of equilibrium point for this model. What’s more, through the use of extreme value analysis model, government funds have been invested in real estate business building devotion principles and the construction base of the real estate businessmen has also been estimated successfully. This provides the corresponding theoretical basis for government macro control policy-making. 展开更多
关键词 real ESTATE MACRO Control THREE-DIMENSIONAL Dynamic model EXTREME Value Analysis
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加热-冷却过程中花岗岩细观热破裂机制
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作者 王飞 邹岩琳 +5 位作者 庞瑞 何本国 范立峰 孟德昊 刘甜甜 石垚 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第10期2138-2147,共10页
由于高温试验设备的限制,在实验室中研究岩石真实热破裂规律通常需要依据冷却后试样的细微观结构观测结果来进行分析推断,无法获得热破裂的实时动态演化过程。为此,基于考虑温度和裂纹滑移效应的节理本构关系,构建花岗岩热力耦合UDEC晶... 由于高温试验设备的限制,在实验室中研究岩石真实热破裂规律通常需要依据冷却后试样的细微观结构观测结果来进行分析推断,无法获得热破裂的实时动态演化过程。为此,基于考虑温度和裂纹滑移效应的节理本构关系,构建花岗岩热力耦合UDEC晶粒模型,以深入探究加热和冷却过程中花岗岩的实时热破裂行为。研究发现,在加热状态下,花岗岩热诱导微裂纹在75℃左右开始萌生,随着温度的升高,微裂纹数量在α→β石英相变温度附近快速达到峰值,但微裂纹密度在600℃降温到25℃的冷却过程中并没有明显变化。虽然冷却效应引起的裂纹数量变化可以忽略不计,但会导致裂纹开度的增加或减少。在加热过程中,微裂纹的萌生主要是由于相邻晶粒的热膨胀不同导致局部应力累积造成的。而石英高温相变引起的细微观结构变化可以增强不同晶粒之间的相互作用,导致晶粒尺度上的压缩和剪切运动加剧,使得热应力裂纹继续变形拓展。在冷却过程中,由于加热过程中热破裂导致的细微观应力释放和冷却效应导致的不同矿物晶体收缩,使得微裂纹的数量虽然不变,但其形态却能发生较为明显的变化,从而使得冷却后花岗岩的宏观应力-应变行为受到很大影响。基于离散元数值模拟对花岗岩热力耦合试验结果作出了细微观阐释,揭示了加热和冷却过程中花岗岩的实时热破裂机制,进一步加深了对高温岩石热力耦合规律的理解。 展开更多
关键词 花岗岩 晶粒模型 实时高温 热破裂
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