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991.
The propagation of shock wave pressure in the tunnel is greatly affected by the tunnel structure, shape, material and other factors, and there are great differences in the propagation law of shock wave pressure in different kinds of tunnels. In order to study the propagation law of shock wave pressure in tunnels with different mate-rials, taking the long straight tunnel with the square section as an example, the AUTODYN software is used to simulate the explosion of TNT in the concrete, steel and granite tunnel, and study on the variation law of shock wave pressure in tunnels with different materials. By using dimensional analysis and combined with the results of numerical simulation, a mathematical model of the propagation law of shock wave pressure in the tunnel is established, and the effectiveness of the mathematical model is verified by making the explosion test of the warhead in the reinforce concrete tunnel. The results show that the same mass of TNT explodes in the tunnel with different materials, and the shock wave overpressure peak at the same measuring point is approximate in the near field. However, there is a significant difference in the middle-far fields from the explosion center, the shock wave overpressure peak in the steel tunnel is 20.76% and 34.82% higher than that of the concrete and the granite tunnel respectively, and the shock wave overpressure peak in the concrete tunnel is 24.91% higher than that in the granite tunnel. Through the experimental verification, getting the result that the maximum relative deviation between the measured value and the calculated value of the shock wave overpressure peak is 11.85%. Therefore, it is proved that the mathematical model can be used to predict the shock wave overpressure peak in the tunnel with different materials, and it can provide some reference for the power evaluation of warhead explosion in the tunnel. 相似文献
993.
994.
针对传统电力用户画像无法全面反映综合能源用户的多类型用能特性,提出了一种数据驱动的中大型能源用户多类型用能特性画像方法。首先,从用电负荷水平、用电稳定性、用电互动能力、用热特性及用冷特性5个方面构建中大型能源用户用能特性综合评价体系。其次,采用客观权重赋权法(criteria importance though intercriteria correlation,CRITIC)对各项指标进行加权计算,分别从短期和中长期两种时间尺度对用户进行评价,实现用户综合用能画像。最后,通过算例分析表明所提方法能全面反映不同类型能源使用特点,为用户用能趋势预测、用能行为优化等业务开展提供了有利条件。 相似文献
995.
996.
为提高配电网故障选相的精确性与灵敏度,针对高阻接地故障及单相断线故障,提出利用测算的偏转角进行故障选相的方法。首先,分析了高阻接地和断线故障选相失败的原因。然后,根据测量的对地参数来判别发生了高阻故障还是断线故障。最后,提出了基于柔性调控零序电压的选相方法,即:向配电网中性点注入零序电流,调控零序电压相角分别为配电网三相相电压相角,通过注入零序电流及返回零序电压测算故障偏转角,结合判据即可实现故障选相。PSCAD仿真结果表明,该方法可快速准确地选出20 k?的单相高阻接地故障相及线路末端断线故障相,且不受故障位置、故障类型、配电网中性点接地方式等因素的影响。 相似文献
997.
基于0.13μm SiGe BiCMOS工艺,设计了一种25 Gbit/s的光接收机前端放大电路单片集成的放大电路。该电路实现了光接收机前端放大电路的单片集成,并采用带反馈系统的跨阻放大器、电感峰化、自动增益控制电路等设计有效提高了增益、带宽和系统稳定性。经仿真与测试,该设计增益达到69.9 dB,带宽为19.1 GHz,并在工业级芯片工作温度(-40℃~+85℃)下带宽误差不超过0.1%。该芯片工作时需要的供电电流为45 mA,功耗为81 mW,信号抖动RMS值为5.8 ps,具有良好的性能和稳定性。本设计提供了一种能够适用于100 Gbit/s(25 Gbit/s×4线)光互连系统的设计方案,具有广泛的应用前景。 相似文献
998.
In this paper, a rare-earth spectral traceability anti-counterfeiting detection technology is proposed. Configure rare-earth samples No.1, No.2 and No.3 with different doping ratios. The spectral signals of these three samples are collected and integrated into a sample library. The traceability anti-counterfeiting detection is to compare the spectral information of the samples to be tested with the established sample library by selecting specific wavelength points for light intensity values. If the sample to be measured meets the light intensity range of the established sample library at a specific wavelength point, the sample model will be output. If it does not meet the light intensity range, the sample to be tested is fake. After testing, the anti-counterfeit rate of samples No.1, No.2 and No.3 can reach 100%. This testing process does not destroy the sample, and the anti-counterfeit effect is unique and reliable. 相似文献
999.
Jie Hu Guangming Liang Qin Yu Kun Yang Xiaofeng Lu 《Digital Communications & Networks》2022,8(3):303-313
Activating Wireless Power Transfer (WPT) in Radio-Frequency (RF) to provide on-demand energy supply to widely deployed Internet of Everything devices is a key to the next-generation energy self-sustainable 6G network. However, Simultaneous Wireless Information and Power Transfer (SWIPT) in the same RF bands is challenging. The majority of previous studies compared SWIPT performance to Gaussian signaling with an infinite alphabet, which is impossible to implement in any realistic communication system. In contrast, we study the SWIPT system in a well-known Nakagami-m wireless fading channel using practical modulation techniques with finite alphabet. The attainable rate-energy-reliability tradeoff and the corresponding rationale are revealed for fixed modulation schemes. Furthermore, an adaptive modulation-based transceiver is provided for further expanding the attainable rate-energy-reliability region based on various SWIPT performances of different modulation schemes. The modulation switching thresholds and transmit power allocation at the SWIPT transmitter and the power splitting ratios at the SWIPT receiver are jointly optimized to maximize the attainable spectrum efficiency of wireless information transfer while satisfying the WPT requirement and the instantaneous and average BER constraints. Numerical results demonstrate the SWIPT performance of various fixed modulation schemes in different fading conditions. The advantage of the adaptive modulation-based SWIPT transceiver is validated. 相似文献
1000.
Zhang Zhe Xiong Hui Xu Tong Qin Chuan Zhang Le Chen Enhong 《Knowledge and Information Systems》2022,64(9):2435-2456
Knowledge and Information Systems - To assure the development of effective treatment plans, it is crucial for understanding the complication relationships among diseases. In practice, traditional... 相似文献