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1.
针对槽钢插打容易引发弯曲失稳的问题,提出了一种沿槽钢设置缀板的构造措施,基于空间配位法提出了一种缀板加劲效应理论,并推导出带缀板槽钢轴压构件的整体稳定性计算方法,为工程中开口槽钢的局部加固优化设计提供了理论依据。算例证明,本方法能够有效量化缀板的位置效应和其自身的尺寸效应,对缀板的数量和板宽、布置方式和构件长度等因素进行稳定临界荷载的规律性分析,计算结果和规律基本合理,充分验证了实际工程的应用效果。  相似文献   
2.
长庆油田作为中国低渗透油藏开发的典型油田,拥有储量巨大的致密油气资源。由于其储集层非均质性强、注采连通性差,油藏采收率普遍不高,亟需对油藏开发单元进行精细描述,以提高中—高含水期井组开发效果。以长庆油田Q011-35井组为研究对象,基于目的层长61砂体接触类型划分,采用微量物质示踪剂监测与油藏数值模拟结合的方法,从平面和剖面综合评价井组水驱效果。结果表明:Q011-35井组储集层非均质性较强,平面上,在西北和正西方向发育高渗条带;剖面上,长$6^2_1$砂体较长$6^1_1$砂体水洗程度高,长$6^1_1$剩余油更富集,明确了砂体连通状态和注采对应关系为剩余油分布的主控因素。微量物质示踪剂监测与油藏数值模拟结合的方法克服了采用单一方法评价井间连通性的局限性,结果更加准确可靠,为精细评价低渗透油藏水驱开发效果、制定剩余油挖潜措施提供借鉴。  相似文献   
3.
针对传统输电线路通道监测方法忽略了对输电线图像的边缘灰度特征检测,导致输电图像轮廓特征不准确,输电线路通道监测出现较大误差的问题,提出基于双程摆扫激光测距探测成像的输电线路通道监测方法.构建双程摆扫激光测距探测成像模型,采用激光传感器实现对双程摆扫激光测距探测节点部署.利用探测模型提取输电线路通道监测双程摆扫激光图像,检测输电线路图像的边缘灰度特征.采用双边滤波器实现对输电线路通道监测的图像增强和降噪处理,构建边缘轮廓特征检测模型,根据图像差异度融合结果实现对输电线路通道监测.仿真实验结果表明,采用该方法进行输电线路通道监测的可靠性较好,监测自动化水平和视觉成像水平较好,提高了输电线路通道监测方法的自适应性和准确性.  相似文献   
4.
TRPM7 plays an important role in cellular Ca2+, Zn2+ and Mg2+ homeostasis. TRPM7 channels are abundantly expressed in ameloblasts and, in the absence of TRPM7, dental enamel is hypomineralized. The potential role of TRPM7 channels in Ca2+ transport during amelogenesis was investigated in the HAT-7 rat ameloblast cell line. The cells showed strong TRPM7 mRNA and protein expression. Characteristic TRPM7 transmembrane currents were observed, which increased in the absence of intracellular Mg2+ ([Mg2+]i), were reduced by elevated [Mg2+]i, and were inhibited by the TRPM7 inhibitors NS8593 and FTY720. Mibefradil evoked similar currents, which were suppressed by elevated [Mg2+]i, reducing extracellular pH stimulated transmembrane currents, which were inhibited by FTY720. Naltriben and mibefradil both evoked Ca2+ influx, which was further enhanced by the acidic intracellular conditions. The SOCE inhibitor BTP2 blocked Ca2+ entry induced by naltriben but not by mibefradil. Thus, in HAT-7 cells, TRPM7 may serves both as a potential modulator of Orai-dependent Ca2+ uptake and as an independent Ca2+ entry pathway sensitive to pH. Therefore, TRPM7 may contribute directly to transepithelial Ca2+ transport in amelogenesis.  相似文献   
5.
新建的龙岩至厦门单线铁路象山隧道断面比较小,使用液压凿岩台车开挖,斜孔掏槽方案受到很大限制。本文介绍了使用液压凿岩台车钻爆开挖象山隧道,选择斜孔掏槽方案实现快速开挖,为类似的隧道工程施工提供经验。  相似文献   
6.
In this paper, we prepare a novel biomimetic caterpillar-like alumina fiber with the characteristic of continuous alumina backbone and fine needle whiskers spine. Then the high-performance caterpillar-like alumina fiber composite proton exchange membrane (CAPEM) is obtained by introducing the amino modified biomimetic caterpillar-like alumina fiber into sulfonated polysulfone (SPSF) matrix, which successfully reasonable construction of the proton conducting channels in both vertical and horizontal orientation. The properties of CAPEM, including proton conductivity, methanol permeability, etc. Are systematically studied. The results show that the proton conductivity of CAPEM increases with rising the temperature, which reaches the maximum of 0.263 S/cm at 80 °C and 100% RH, respectively. The excellent proton conductivity of CAPEM is attributed to the long-range continuous proton conducting channel formed by the horizontal continuous alumina skeleton in the in-plane direction and the vertical overlapped fine needle whiskers spine in the through-plane direction. In addition, the interfacial compatibility between amino modified caterpillar-like alumina fiber and SPSF matrix is enhanced through the reasonable construction of proton conducting channels, which effectively inhibits the methanol permeation of the composite membrane with 4.18 × 10?7 cm2 s?1 and improves the comprehensive performance of the CAPEM.  相似文献   
7.
Higher transmission rate is one of the technological features of prominently used wireless communication namely Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO–OFDM). One among an effective solution for channel estimation in wireless communication system, specifically in different environments is Deep Learning (DL) method. This research greatly utilizes channel estimator on the basis of Convolutional Neural Network Auto Encoder (CNNAE) classifier for MIMO-OFDM systems. A CNNAE classifier is one among Deep Learning (DL) algorithm, in which video signal is fed as input by allotting significant learnable weights and biases in various aspects/objects for video signal and capable of differentiating from one another. Improved performances are achieved by using CNNAE based channel estimation, in which extension is done for channel selection as well as achieve enhanced performances numerically, when compared with conventional estimators in quite a lot of scenarios. Considering reduction in number of parameters involved and re-usability of weights, CNNAE based channel estimation is quite suitable and properly fits to the video signal. CNNAE classifier weights updation are done with minimized Signal to Noise Ratio (SNR), Bit Error Rate (BER) and Mean Square Error (MSE).  相似文献   
8.
堰塞坝溃决物理概化试验是当前研究堰塞坝溃决机理较为可行的方法,但在现有堰塞坝溃决试验中,由于试验坝体尺寸较小、试验上游库容不足,导致试验的溃决过程与实际堰塞坝溃决存在较大差异。为尽量克服库容的不足所带来的影响,本文采用了最大库容达380m3的大尺度堰塞坝溃决试验系统。本文以无粘性、宽级配砂砾料堰塞坝为对象开展了多组室内大尺度溃决试验来揭示堰塞坝溃决机理,并通过设置不同背水面坝坡来研究其对溃决过程的影响。通过试验发现堰塞坝溃决过程可以分为沿程冲刷、溯源冲刷、快速发展和溃口稳定四个阶段。在溃决过程中发现陡坎侵蚀和溃口两侧土体失稳坍塌是溃口快速发展的主要机理。不同背水面坡度下的沿程冲刷阶段冲蚀特征基本相似,而溯源冲刷阶段及快速发展阶段溃决过程差异显著,较大的背水面坡度使溯源冲刷阶段跌坎水流更容易得到发展,进而影响溃口处的垂向冲深及侧向发展,导致快速发展阶段更易形成垂向落差较大的陡坎洪水冲蚀。从溃决历时来看,坡度的增加使溃口发展更快、峰值流量出现时间更早,进而导致溃决历时缩短。坝顶溃口宽度及峰值流量也会随着坡度的增加而增加。在本试验还较好地重现了天然堰塞坝下游河道两岸的淤积现象,并根据堰塞坝溃决过程中的水流特点、泥沙运动及溃决完成后下游河道的地貌,初步分析了淤积区的形成机理。  相似文献   
9.
To improve the efficiency and fidelity of the numerical analysis for cascade flutter, we propose an efficient scale-resolving simulation method dedicated to time-periodic flows by incorporating the harmonic balance approach into the large-eddy simulation. This method combined convergence calculations of the steady-state problem based on the harmonic balance method for periodic components, and the nonlinear time-marching method for turbulent fluctuations. Using the proposed method, deterministic periodic components and stochastic turbulent fluctuations were calculated simultaneously, and the effect of turbulent fluctuations on deterministic periodic components was directly calculated without using turbulence models. In this paper, we explain the algorithm and feature of this simulation technique and present the results of the computation for channel flow excited in the streamwise direction as an analysis example using the proposed method. In order to validate the proposed method, an analysis of sinusoidally pulsating channel flow at the central friction-velocity Reynolds numbers Rer = 180 was conducted, confirming that the amplitude and phase of the mean velocity oscillation computed by the proposed method were in good agreement with those of the conventional LES. The present calculation achieved an order of magnitude improvement in computational efficiency compared to conventional LES.  相似文献   
10.
In the current work, numerical simulations are achieved to study the properties and the characteristics of fluid flow and heat transfer of (Cu–water) nanofluid under the magnetohydrodynamic effects in a horizontal rectangular canal with an open trapezoidal enclosure and an elliptical obstacle. The cavity lower wall is grooved and represents the heat source while the obstacle represents a stationary cold wall. On the other hand, the rest of the walls are considered adiabatic. The governing equations for this investigation are formulated, nondimensionalized, and then solved by Galerkin finite element approach. The numerical findings were examined across a wide range of Richardson number (0.1 ≤ Ri ≤ 10), Reynolds number (1 ≤ Re ≤ 125), Hartmann number (0 ≤ Ha ≤ 100), and volume fraction of nanofluid (0 ≤ φ ≤ 0.05). The current study's findings demonstrate that the flow strength increases inversely as the Reynolds number rises, which pushes the isotherms down to the lower part of the trapezoidal cavity. The Nuavg rises as the Ri rise, the maximum Nuavg = 10.345 at Ri = 10, Re = 50, ϕ = 0.05, and Ha = 0; however, it reduces with increasing Hartmann number. Also, it increase by increasing ϕ, at Ri = 10, the Nuavg increased by 8.44% when the volume fraction of nanofluid increased from (ϕ = 0–0.05).  相似文献   
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