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飞机实施人工影响天气作业,具有覆盖范围广,作业效果好的优点,是未来人工影响天气工作的发展方向。但人影作业飞机内部工作环境复杂,工作人员的正常语言交流会受到飞机引擎、机舱内设备、飞机外部等噪声的影响,甚至无法正常交流。因此,需要设计一种语音增强装备或设施来消除噪声,方便人影飞机上工作人员的正常沟通交流。从理论上阐述了参数法、非参数法、统计方法及其他语音增强算法。重点研究了维纳滤波法、谱减法和基于短时对数谱幅度的MMSE算法,并对这三种语音增强算法都进行了实验仿真,对比了各种算法的优缺点。针对人影飞机的特定工作环境,提出基于短时对数谱幅度的MMSE算法比较适合用于人影飞机上进行语音增强,消除噪音。 相似文献
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一、前言 众所周知采用汽轮机抽汽加热给水,可提高循环热效率。如何选择最佳抽汽点,前人提出了等焓升法、等温升法和几何分配法等方法,这些方法对于现代高参数大容量汽轮机已不适用。本文从最优化角度新提出了矩阵正多面体优化方法,用此法可确定最佳回热参数。 相似文献
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针对蒸气压缩式制冷循环的特点,提出了制冷参数测量仪的设计方案。通过测量制冷系统的蒸发温度、蒸发压力、冷凝温度、冷凝压力这四个参数,并结合饱和蒸汽表或压焓图、热力学基本性质和马丁-侯方程,可获得制冷系统性能参数和热力学参数;为满足高精度的参数测量,设计了可靠的恒流源电路;为解决压力传感器的温度漂移设计了二元曲线拟合的方法,补偿后的最大相对误差为0.53%。仪表具有制冷、制热、自动、真空度、气密性多种测量模式,可通过USB与上位机通讯,可用于空调、冰箱等单工质制冷系统测量,支持30余种冷媒。该仪表的研制填补了国内制冷领域专业数字式测量仪表的空白。 相似文献
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基于极性叠加原理,在成功设计烷烃异构体和多氯代烷烃生成焓计算新方法的基础上,设计了一种计算多元醇异构体生成焓的新方法,并合理地假定任一异构体的原子化焓等于三种键(C-C、C-H和C-O-H键)的键能、极性叠加能项以及氢键能项的加和。用这一模型拟合24种原子化粹数据,得到了标准生成焓的估算公式。为了检验预测的精确性,又设计了一种预测方法,使用在排除液预测的化合物条件下回归得到的参数,预测该化合物的生成焓。按这种方法,预测了24种异构体的生成焓。通过该5参数预测的相对于实验值的各种误差(平均绝对误差、均方根误差和最大绝对误差)不仅比7参数的基团法预测的对应误差小得多,而且比相应实验数据的误差还要小。与键加和法比较,该方法的模型包含了极性叠加能和氢键能量,该两项代表了主要的非键相互作用能,表征了不同异构体的结构差异,并大大减少了参数。 相似文献
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信道匹配方法在有源探测领域是一种重要的提升检测信噪比的方法。针对非确知海底参数环境下的有源探测信道匹配问题,提出一种结合卷积神经网络进行信道匹配的算法。该算法基于海底参数扰动开展声场仿真生成卷积网络训练数据;首先通过分类网络将信号按照海底底质类型分类,在每个分类区间内采用单独的卷积网络反演海底参数;然后结合声场模型估计信道传递函数,进行信道匹配,从而在非确知环境下抑制多途影响,提升回波检测能力。仿真与实验结果表明,该算法能够在不确知海底环境条件下,有效估计信道传递函数,实现信道最优化匹配,在实验条件下可提高回波检测信噪比4 dB左右。相比传统方法,该算法可以在海底参数不确知条件下对低接收信噪比的信号实现信道匹配,同时不需要高信噪比的实验参考信号,有效提高了信道匹配方法的环境宽容性。 相似文献
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Ersin Kantar 《哲学杂志》2019,99(13):1669-1693
In this study, effective-field calculations within Ising model framework have been utilised to investigate theoretically the effect of temperature and interaction parameters on the magnetic and hysteretic processes in an idealised system used to represent endohedral fullerene (EF) with a dopant magnetic atom confined within a spherical cage. The thermal behaviour of the partial (centre and surface) and the total magnetizations are studied to determine the character of phase transition (continuous and discontinuous) and to elaborate the phase diagram in interaction parameters plane. The total and partial hysteresis curves with susceptibility peaks and coercive fields are also given and focused on the influence of the temperature and interaction parameters. According to values of Hamiltonian parameters, the system exhibits the first- and second-order phase transitions and three types of compensation behaviour, namely Q-, R-, and S-types. In the phase diagram of the system, when the centre–surface (C–S) interaction increases or decreases, the phase transition temperature increases symmetrically. Finally, from the hysteresis curves of the system, we observed that type II superconducting-like behaviour can appear by the presence of dopant centre magnetic atom. 相似文献
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大气温度廓线及其时间演变特征资料在地球科学领域具有重要的应用,为获取高时空分辨的大气温度的垂直分布,建立了瑞利-拉曼温度测量激光雷达。介绍了瑞利-拉曼激光雷达进行温度测量的主要原理和研制的瑞利-拉曼激光雷达的主要参数;数据处理方面,通过背景噪声剔除和小波算法降噪提高系统的信噪比;使用研制的激光雷达对大气温度廓线进行观测,将观测结果与大气模式数据和卫星观测结果进行对比,均显示较好的一致性,证明了激光雷达温度测量结果的准确性,其温度测量数据可以用于气象学研究。 相似文献
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本文提出了一种供热温度为80~100℃的新型空气源高温热泵循环(EIHP),该循环采用非共沸混合工质R290/R600a,利用内部自复叠技术和喷射器提升循环性能。针对EIHP循环建立了相应的热力学计算模型,并与传统热泵循环(CHP)进行了对比研究。根据计算结果,当冷凝器出口温度为100℃,蒸发器出口温度从25℃下降到-10℃时,相较于CHP循环,EIHP循环的COP提高了15%~27%,压缩机压比降低了20%~46%,容积制热量提高了22%~51%。此外,本文还研究了冷凝器出口温度,工质配比等参数对循环性能的影响情况。 相似文献
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The quasi-chemical expression for weakly interacting binary alloy has been applied to obtain energy parameters and their temperature derivatives for Na–K liquid alloy at 384?K. These energy parameters have then been used to calculate thermodynamic functions, such as free energy of mixing, heat of mixing, entropy of mixing and microscopic functions, such as concentration fluctuation in long wavelength limit, Warren–Cowley short-range order parameter, ratio of mutual and self-diffusion coefficients. The analysis reveals that the energy parameters are temperature dependent and the Na–K liquid alloy at 384?K is a weakly interacting homocoordination system. The observed thermodynamic properties of Na–K alloy in molten state have successfully been explained by assuming Na2K complex on the basis of the quasi-chemical formalism for a weakly interacting system. 相似文献
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To obtain the maximum output of a copper vapor laser (CVL), 8 parameters of the CVL system including the length and radius of the laser tube, the peak voltage, the repetition frequency, the wall temperature and the LC parameters of the discharge circuit are optimized by using a genetic algorithm. The optimization has increased the laser power by 89% from primary 91 W (corresponding to the empirical configuration for the CVL system used in an experiment) to 172 W (the efficiency has also been increased from primary 1 to 1.16%). 相似文献
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Detection of multi-spin interaction of a quenched XY chain by the average work and the relative entropy 下载免费PDF全文
《中国物理 B》2021,30(9):90504-090504
We investigate the nonequilibrium thermodynamics of a quenched XY spin chain with multi-spin interaction in a transverse field. The analytical expressions of both the average work and the relative entropy are obtained under different quenching parameters. The influences of the system parameters on the nonequilibrium thermodynamics are investigated.We find that at finite temperature the critical phenomenon induced by the multi-spin interaction and the external field can be revealed by the properties of the system nonequilibrium thermodynamics. In addition, our results indicate that the average work and the relative entropy can be used to detect both the existence and strength of the multi-spin interaction in the nonequlibrium system. 相似文献