课程文献中心 更多>>

关键词： MATLAB  

摘要： This paper reports on the development of a numerical tool tailored to perform energy and environmental analyses for an H2PEM power station, comprising fuel cell and electrolysis units, with a dual-mechanism H2 storage that incorporates compression and metal hydride tanks. A comprehensive methodology for the design, modeling, and simulation is introduced, focusing on the interaction of the H2PEM with a higher-level network that exchanges electrical power. The H2PEM is 1 kW level, with a H2 storage capacity of 5 Nm3. The work stands out for the modeling of subsystem interconnections under a strategic operational plan, offering an integrated understanding of system behavior. The modeling includes temperature regulation, encompassing the assessment of heat management, as well as that of the auxiliaries. Steady state and dynamic simulations are conducted within the Matlab/Simulink computational environment to assess the performance under various conditions. The energy and environmental analyses comprise determining key parameters such as involved energies, hydrogen production and consumption, state of charge of the hydrogen reservoir, CO2 emissions and savings, and associated temperature changes. Three case scenarios are assessed, considering H2PEM interacting with a network powered by: (1) solely fossil-based electricity, (2) the Italian energy mix for 2023, and (3) entirely renewable energy sources. Results revealed nominal efficiency of 55% for the electrolyzer and 40.5% for fuel cell. About 1 order of magnitude of CO2 is saved when the H2PEM is totally renewable (93.36 vs. 1.539 kgCO2 kgH2-1). The temperature increase associated is 10.5 x 10-3 degrees C per ppm of CO2 emitted.

关键词： 施工技术   建筑屋面防水   养护措施  

摘要： 对屋面采用防水技术,需要与实际情况相结合,使建筑工程施工质量有所提高.所以,深入研究建筑工程施工中所应用的屋面防水技术非常必要.为解决建筑房屋渗漏水问题,对土木工程建筑屋面防水技术进行了研究,重点分析了屋面防水技术存在的问题,提出了建筑屋面防水技术的应用要点,包括屋面防水施工要求、屋面找平层施工、防水材料选择、防水分隔缝作业、屋面防水层施工,并对施工质量控制要点进行了探讨,以期为相关工程提供参考.

关键词： 钢结构住宅建筑   安装施工   关键技术   要点  

摘要： 近年来,钢结构在住房构建领域的创新运用日益广泛,它不仅满足了现代住宅对审美设计的高要求,而且还展现了无可比拟的轻量化、施工便捷以及可循环利用等优势.虽然钢结构已经成为现代住宅设计的新宠儿,取得了一定的成功实践,但其发展尚处初级阶段,随之而来的问题亟待寻求创新的解决之道.因此,对钢结构住宅建筑安装施工关键技术要点进行分析,以供参考.

关键词： 建筑工程   岩土工程   勘察要点  

摘要： 为做好建筑工程岩土勘察工作,提升建筑工程建设质量,就建筑工程岩土勘察要点进行分析,首先阐述了岩土工程勘察的目的和内容,其次分析了岩土工程勘察的重要性,最后对岩土工程勘察存在的问题进行探讨,并提出相关的解决策略,以期提升勘察质量,推动建筑行业的健康发展,并为相关人员提供一定的参考和借鉴.

关键词： Amorphous silicon solar cells   Electromagnetic waves   MATLAB   Multilayer thin film   Transfer matrix method  

摘要： Enhancing the quantum efficiency of transparent multilayer solar cells is crucial for advancing the field of renewable energy. The aim of this study is to develop a model for transparent thin-film solar cells with high efficiency. The polyvinyl alcohol doped by NaI was prepared in a laboratory. The PVA's complex refractive indices were measured to be used in a proposed model for transparent solar cells using MATLAB code. This code calculates quantum efficiency through materials optical properties using the Transfer Matrix Method. A transparent multilayer thin-film silicon solar cell was proposed using Polyvinyl Alcohol (PVA)-A water-soluble synthetic polymer (PVA) 10% NaI as the substrate and protective layer. The external quantum efficiency reached 66.62, with a short-circuit current of 31.66 mA/*** model shows that using PVA with 10% NaI in an amorphous silicon multilayer thin-film solar cell achieves the highest external quantum efficiency. The researchers concluded that with an increase in doping with NaI salt, the minority charge carriers contributed to the increase in the current with the participation of sodium and iodine ions. However, an increase in the doping by more than 10 percent contributes to the charge carriers of polyvinyl alcohol impurities, reducing the effect of movement;thus, the current decreases again.

关键词： SPICE   Circuits   Object oriented modeling   Mathematical models   MATLAB   Transformers   Software   Integrated circuit modeling   Gyrators   Magnetic domains  

摘要： Equivalent circuits (EC) and bond graphs (BG) are inventive approaches to represent energy interactions in complex multidomain systems. Undergraduate and graduate students in engineering and physics courses benefit from such intuitive representations as alternatives to abstract space-state models and block diagram forms. However, differences between EC and physical counterparts frustrate their implementation and simulation in network analysis software like the widespread SPICE-based ones. Therefore, this paper proposes a method for converting EC and BG into realizable models through modulated effort/flux sources supported by systematic node labeling. Comparative transient simulations in LTspice and MATLAB encompass examples of mechanical, electrical, and magnetic systems, yielding compatible results apart from the multidomain interfaces. The presented technique supports elaborated models’ development and validation through an open-source and lightweight software, motivating further applications in didactic projects and virtual labs.

关键词： 水利工程   水闸   设计要点  

摘要： 为提高水利工程中水闸设计的合理性,分析水闸设计的基本原则和目标,包括安全性、可靠性和经济性等,提出了水闸设计的要点,包括水流特性、结构稳定性、安全措施、设备可靠性、经济效益等,并阐述了水闸设计的注意事项,为水利工程相关人员提供了实践参考,以确保水闸设计的质量和可持续发展.

关键词： Remote and satellite sensing   Groundwater storage   Downscaling method   Alluvial aquifers   Iran  

摘要： A method to downscale annual groundwater storage variations from large-scale, satellite-derived estimates to individual aquifers is presented, employing a simple linear regression approach based on the water balance principle. The method relies on groundwater storage changes derived from the gravity recovery and climate experiment (GRACE). Seven alluvial aquifers, ranging in area from approximately 145 to 1300 km(2) in Fars Province, Iran, were selected as case studies to evaluate the applicability of the proposed downscaling method. The results indicate that groundwater storage at the GRACE scale (similar to 31,416 km(2)) has depleted by 229 million cubic meters (MCM) per year during the study period (2002-2015). The correlation coefficients between downscaled and actual groundwater storage depletions varies from 0.655 to 0.891, with an average of similar to 0.82 across the seven aquifers, demonstrating the method's ability to provide acceptable downscaling results. Downscaling results indicate that the alluvial aquifers of Aspas, Namdan, Beiza-Zarghan, Dehbid, Abadeh-Eghlid, Bakan, and Sidan-Farugh have experienced groundwater storage depletions of 17.71, 34.49, 46.21, 13.88, 14.11, 6.78, and 22.62 MCM per year, respectively, from 2002 to 2015, which correspond to water table declines of 0.915, 0.656, 0.822, 0.538, 0.725, 1.395, and 1.435 m/year, respectively. As a final point, this study proposes a downscaling method that can be applied to address groundwater storage variations at aquifer scales, particularly in regions with unavailable or limited data.

关键词： data time-normalization   functional near-infrared spectroscopy   spline interpolation   self-paced tasks   MATLAB  

摘要： Functional near-infrared spectroscopy (fNIRS) is particularly suitable for measuring brain activity during motor tasks, due to its portability and good motion tolerance. In such cases, the trials' duration may vary depending on the experimental conditions or the participant's response, therefore a comparison of hemodynamic responses across repetitions cannot be properly performed. In this work, we present a MATLAB (R2023a) function (TaskNorm.m) developed for time-normalizing fNIRS data recorded during trials with different durations. It is based on a spline interpolation method that rescales the time -axis to the percentage of the trial with a fixed number of samples. This allows us to successively average across repetitions to obtain the mean hemodynamic responses and complete the standard data processing. The algorithm was tested on eight subjects (four with developmental coordination disorder, age: 9.78 +/- 0.30 and four typically developing children, age: 9.02 +/- 0.30) performing three different tasks. The results show that the TaskNorm function works as expected, allowing both a comparison and averaging of the data across multiple repetitions. The performance of the function is independent of the task or the pre-processing pipeline applied. The proposed function is publicly available and importable into the HomER3 package (v1.72.0), representing a further step in the ongoing standardization process of fNIRS data analysis.

关键词： 装配式混凝土结构   构件运输与存放   灌浆操作   连接技术  

摘要： 文章旨在深入分析装配式混凝土建筑结构工程施工的技术要点,探讨其在提升施工效率、提高施工效益、确保施工准确度以及实现节能减排等方面的优势.通过对构件运输和存放、PC板安装、灌浆操作、连接技术、墙体混凝土浇筑、预制楼梯板安装以及预制叠合板安装等施工工艺的详细阐述,为装配式混凝土建筑结构工程施工提供全面的技术参考.