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71.
岩体非线性特征随深度增加不断凸显,其力学参量现场实时精确测量及长期监测,为地应力解除过程中岩体变化特征及应力监测提供了必要的基础。然而目前岩石力学参量测定多基于室内力学试验,时效性及拟合方法都会对测试结果带来误差。传统耦合超声波发射、接收探头对接触面平整性要求高,无法实现布置于现场钻孔内的长效监测。基于干耦合点接触声波探头测速技术,通过对声波发射、接收探头设计,电路板稳定性及去噪算法研究,研发出具有瞬时采集、无线传输功能的数字化波速采集系统。通过对同一区域取自现场加工的?50 mm×100 mm花岗岩岩样及地应力解除岩芯,分别进行室内力学试验及波速测定,以计算获取相应静态、动态弹性模量。结果表明:首先,自研发基于干耦合点接触声波测速采集系统,对不同工作接触面适应性较好,数据误差在规范允许范围内。其次,对于同一区域相同岩性不同尺度、形态的岩样,其动态、静态弹性模量关系彼此间具有适用性。这就为现场基于干耦合点接触声波测速计算获得的岩体动态弹性模量,推算其静态弹性模量提供了依据。进一步的,基于干耦合点接触声波测速数字化采集系统,岩体动、静态力学参数在现场地应力岩芯解除过程及岩体长期监测过程中的实时采集及分析研究,具有一定的可行性。 相似文献
72.
《International Journal of Hydrogen Energy》2021,46(80):40217-40238
The primary purpose of this work is to develop a novel model for comprehensively investigating the hydrogen storage performance under the framework of diffusion of hydrogen atoms through hydride layer. The proposed model is constructed upon perfectly mathematical-physical equations, by taking into account complicated multi-scale and multi-physics coupling actions. Importantly, three-dimensional numerical simulations are performed to explore the coupling effects of micro diffusion, mesoscopic permeation, and macroscopic fluid flow. An analytical approach accounting for the characteristics of reaction bed, particle, and crystal grain is presented as well. In addition, a parametric analysis is conducted to reveal that the hydride particle dimension, particle porosity, grain size, and diffusion coefficient of reacted layer have a significant effect on overall hydrogen storage performance, highlighting that grain size and hydrogen diffusion coefficient are vital factors that need to be considered for material preparation and design. 相似文献
73.
Industrial facilities usually need multiple energy subsystems, e.g., for heat, cold, and electric power supply. Normally, these energy subsystems are controlled locally and independent of each other. Coupling of the different subsystems can open up additional potential. Fraunhofer IISB has developed a demonstration and research platform for investigating the benefits of such sector coupling. A major precondition is to understand the energy flows in the system and establish an overall and flexible system control to realize the required algorithms for setting up an intelligent decentralized energy system. Major components of the overall system are various storages, which extend the degree of freedom for sector coupling and increase the effectiveness of the different subsystems. 相似文献
74.
75.
设计创新能力培养已成为21世纪风景园林学规划设计教学核心,在此背景下,由知识传输导向的教学模式正逐步转变为由设计与科研并肩引领知识增长的教学模式,数字化景观规划设计教学体系与方法成为当代风景园林教育亟待充实并应用的重要内容。立足风景园林教学前沿,基于对当代风景园林规划设计教育的系统把握,以东南大学风景园林专业教学实践为例,提出整合数字景观技术平台,构建“浸入式”数字技术教学环境,实现数字平台与教学体系的协同创新;继而针对传统教学方法局限,利用数字化教学平台进行“耦合教学法”创新实践,加强实证性知识体系集成融合,实现风景园林规划设计课程教学模式的系统探索与实践。 相似文献
76.
Min Yuan Jie Wang Li Wang Fu Zhong Kunlan Huang Yankang Tian 《Ceramics International》2021,47(3):3747-3759
This work proposes the application of pulsed electromagnetic coupling field processing (EMCFP) to enhance the lifetime and cutting performance of WC-15TiC-6Co cermet tool for the first time. Firstly, the developed electromagnetic field coupling equipment is introduced, the treatment process is analyzed, and the magnetization characteristics of WC-15TiC-6Co cermet tool are evaluated. Secondly, the strengthening effect of the EMCFP treatment is demonstrated by mechanical properties testing and cutting experiments, which reveal that the optimally treated tools exhibit a fracture toughness increased by 18%, an average cutting temperature decreased by 10%, and a friction coefficient for the rank face decreased by 7.9%. Collectively, these enhancements result in a tool lifetime increased by a factor of 1.92 relative to the lifetime of untreated tools. In addition, the results of simulation demonstrate that the simultaneously pulsed magnetic and electric fields contribute toward greater magnetic flux density and current density on the surface of the WC-15TiC-6Co cermet tool than would be obtained from the magnetic and electric fields alone. 相似文献
77.
Mei Ying Liu Tu Lai Sun Xiao Li Zhu Xiao Qiang Liu He Tian Xiang Ming Chen 《Journal of the American Ceramic Society》2021,104(12):6393-6403
Hexagonal rare-earth ferrites (h-RFeO3) have attracted much scientific attention due to their room-temperature multiferroicity. However, it is still a hard job to obtain h-RFeO3 bulk materials because of the meta-stability of such hexagonal phase, and the evaluation of room-temperature ferroelectric and magnetoelectric characteristics in such materials is also a challengeable issue. In the present work, Yb1−xInxFeO3 ceramics with the stable hexagonal structure were obtained by introducing chemical pressure, where the unique ferroelectric domain structures of sixfold vortex combined with tenfold vortex with a typical size of ~400 nm were determined. Symmetry of the present system evolved from centrosymmetric orthorhombic Pbnm (x = 0–0.4) to non-centrosymmetric hexagonal P63cm (x = 0.5 and 0.6) with a ferroelectric polarization up to 3.2 μC/cm2, and finally to centrosymmetric hexagonal P63/mmc (x = 0.7 and 0.8). The Curie point decreased monotonically from 723 K to a temperature below room temperature with increasing x, and the antiferromagnetic phase transition above room temperature was determined for all compositions. Meanwhile, a large linear magnetoelectric coefficient (αME) up to 0.96 mV/cm Oe was obtained at room temperature, and this indicated the great application potential for magnetoelectric devices. 相似文献
78.
79.
Livia Pagano Angelo Toto Francesca Malagrin Lorenzo Visconti Per Jemth Stefano Gianni 《International journal of molecular sciences》2021,22(2)
Quantitative measurement of intramolecular and intermolecular interactions in protein structure is an elusive task, not easy to address experimentally. The phenomenon denoted ‘energetic coupling’ describes short- and long-range interactions between two residues in a protein system. A powerful method to identify and quantitatively characterize long-range interactions and allosteric networks in proteins or protein–ligand complexes is called double-mutant cycles analysis. In this review we describe the thermodynamic principles and basic equations that underlie the double mutant cycle methodology, its fields of application and latest employments, and caveats and pitfalls that the experimentalists must consider. In particular, we show how double mutant cycles can be a powerful tool to investigate allosteric mechanisms in protein binding reactions as well as elusive states in protein folding pathways. 相似文献
80.
台头焦煤7202运输顺槽进过程中存在弱胶结膨胀软岩地层,支护难度大。为解决该问题,进行耦合模拟研究,结果表明,普通锚杆支护在90 d左右时会出现巷道垮塌现象,结合顶板离层仪观测数据,表明模拟结果真实可靠。对巷道支护优化方案,采用工字钢结合管棚锚喷技术,实施完成进行效果考察,考察结果显示优化方案有效解决了弱胶结软岩支护难度大的问题。 相似文献