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中国传统食品“型、名、意”之谐  [PDF]
王武,虞昊
- , 2016, DOI: 10.3979//j.issn.1673-1689.2016.04.001
Abstract: 大凡经世千载的民间食品,其“型”融于“名”,且隐于“意”。作者从促进中华传统食品非物质文化遗产挖掘的角度出发,借助多学科交叉纵横谈,领悟以圆、方、角、条为基型的食品渊源,以及中华食品“型、名、意”之间交互贯通的历史背景和文化轶趣。指出中华食品非遗保护的真谛,乃基于传承食品物性之外的更深层次的人文属性。呼吁唾弃地方保护主义,弃小见大、清源正本、返璞归真,推动有中华食品内涵特色的可持续发展。
The names of Chinese foods usually comprise the shape characters. In order to explore the profound culture connotations of traditional Chinese foods as the non-material cultural heritage, the stereoscopic constitution, nomination, historical development and cultural significance are integrally pondered, which is based on the disciplinary crossing-over principle. In this article, the historical background and cultural anecdotes of Chinese foods, especially with the shapes in round, square, triangle and strip, are discussed. It points out that the significance of protecting the character of Chinese food as the non-material cultural heritage lies in the rational exploration of its humanistic connotation, and the promotion of its sustainable development as well
Nanostructuring of Ba8Ga16Ge30 clathrates  [PDF]
Vicente Pachecoa,Raul Cardoso--Gil,Deepa Kasinathan,Helge Rosner,Maik Wagner,Lorenzo Tepech--Carrillo,Wilder Carrillo--Cabrera,Katrin Meier,Yuri Grin
Physics , 2011,
Abstract: First thermoelectric properties measurements on bulk nanostructured Ba8Ga16Ge30 clathrate-I are presented. A sol-gel-calcination route was developed for preparing amorphous nanosized precursor oxides. The further reduction of the oxides led to quantitative yield of crystalline nanosized Ba8Ga16Ge30 clathrate-I. TEM investigations show the clathrate nanoparticles retain the size and morphology of the precursor oxides. The clathrate nanoparticles contain mainly thin plates (approx. 300 nm x 300 nm x 50 nm) and a small amount of nanospheres (diameter ~ 10 nm). SAED patterns confirm the clathrate-I structure type for both morphologies. The powders were compacted via Spark Plasma Sintering (SPS) to obtain a bulk nano-structured material. The Seebeck coefficient S, measured on low-density samples (53% of {\delta}x-ray), reaches -145 {\mu}V/k at 375 {\deg}C. The ZT values are quite low (0.02) due to the high resistivity of the sample (two orders of magnitude larger than bulk materials) and the low sample density. The trend of the temperature dependence of S is in agreement with the values obtained from electronic structure calculations and semi-classical Boltzmann transport theory within the constant scattering approximation. The total thermal conductivity (1.61 W/mK), measured on high density samples (93% of {\delta}x-ray), shows a reduction of 20-25% in relation to the bulk materials (2.1 W/mK). A further shaping of the sample for the Seebeck coefficient and electrical conductivity measurements was not possible due to the presence of cracks. An improvement on the design of the pressing tools, loading of the sample and profile of the applied pressure will enhance the mechanical stability of the samples. These investigations are now in progress.
用MBS和XPS究负载型氧化铁催化剂载体与活性组分的相互作用  [PDF]
丁莹如,岳瑛,金永漱
分子催化 , 1989,
Abstract: 负载型催化剂具有高分散度、抗烧结、使用寿命长、机械性能好等优点,使用非常广泛.作为载体并非全是“惰性”的.载体与活性组分间常有不同程度的相互作用.这类催化剂载体与活性组分之间的相互作用能明显改变活性组分的颗粒大小、还原度以及催化、氧化
Thermoelectric properties of two-dimensional slabs of Ba8Ga16Ge30 from first principles  [PDF]
Deepa Kasinathan,Vicente Pacheco-Espejel,Helge Rosner
Physics , 2011,
Abstract: Thermoelectric effects enable the direct conversion between thermal and electrical energy and provide an alternative route for power generation and refrigeration. The clathrate Ba8Ga16Ge30 has the highest figure of merit (ZT ~ 1) among other members in the family of type-I inorganic clathrates. Enhancement of the thermoelectric properties have been observed in multilayered superlattices, quantum wires and in nanostructured materials, either due to the increase in power-factor (S^{2}\sigma) or due to the reduction of lattice thermal conductivity (\kappa). Here, we investigate the thermoelectric properties of two-dimensional slabs with varying thickness of Ba8Ga16Ge30 using semi-classical Boltzmann transport theory with constant scattering approximation. We observe that, there exists a delicate balance between the electrical conductivity and the electronic part of the thermal conductivity in reduced dimensions and the insights from these results can directly be used to control particle size in nanostructuring experiments. The calculated properties are consistent with the recent, first measurements on bulk nanostructured samples.
电机端盖超谐共振分析  [PDF]
杨志安,冯宏伟
工程力学 , 2012, DOI: 10.6052/j.issn.1000-4750.2011.01.0032
Abstract: 根据电机端盖的结构特点,将端盖抽象为圆环板。按照弹性力学理论建立了圆环板的振动方程。基于伽辽金方法,引入振型试函数,得到5种不同边界条件端盖的非线性振动方程。应用多尺度法得到系统超谐共振近似解。计算了5种边界条件下超谐共振的幅频响曲线。分析了半径、激励对系统超谐共振响应曲线的影响。
圆谐展开在特征识别中的新应用  [PDF]
母国光
科学通报 , 1988,
Abstract: 用圆谐滤波器做相关识别具有同时满足平移和转动不变的优点,但是这种转动不变性的获得是以牺牲了一定的相关峰的信噪比为代价的。为了既保持滤波器具有平移和转动不变性又具有高的相关峰的信噪比,我们提出了用位相型圆谐滤波器做相关识别的新方法,并用
多谐次相位法在柴油机故障诊断上的应用  [PDF]
肖小勇,向阳,钱思冲,李瑞,周强
哈尔滨工程大学学报 , 2014, DOI: 10.3969/j.issn.1006-7043.201306050
Abstract: 为了探究多缸机瞬时转速多谐次相位实用诊断方法,以内燃机扭振理论为基础,建立了瞬时转速的谐次诊断模型,从理论上分析了故障态下瞬时转速谐次幅值和相位的变化规律,并结合4120SG型柴油机单缸与多缸故障试验研究,提出了基于瞬时转速多谐次相位分析法的柴油机定位诊断技术,并提取了以谐次幅值和谐次相位为主的缸内做功故障诊断指标,确定了单缸与双缸故障态下瞬时转速的谐次诊断规则,并应用于实船12缸柴油机的故障诊断,取得了很好的效果。
逆变器消谐方程实时精确解的通用初值研究  [PDF]
陈祥训,王宇红,陈雷,王轩,兰越前,武丹
中国电机工程学报 , 2015, DOI: 10.13334/j.0258-8013.pcsee.2015.18.023
Abstract: 提出2种确定逆变器消谐方程初值的方法:基波平衡型优化方法(FCBO)与伏-秒平衡型基波优化方法(VSBO)。2种方法都将参考正弦波s(θ)=Usinθ的一个周期2π均匀分为宽度为θ0=2π/Np的Np个子区。每个子区分配一个开通角待定、关断角在子区下边界的PWM脉冲pn(θ)。FCBO法令各个子区的局部正弦波形sn(θ)与该区的脉冲pn(θ)的基波系数相等,VSBO法令sn(θ)与pn(θ)的伏-秒积相等来确定各自pn(θ)的开通角。在此基础上开发出了2种算法简单的通用初值计算公式,对于每一种Np值都只须计算一次初值即可用来求取各种调制系数ma时的消谐方程的实时精确解。借助于通用初值得到的各种条件的消谐方程实时精确解,对初值、真值间接近程度与快速精确求解消谐方程的关系,影响消谐方程精确求解的决定性因素,消谐方程精确解的唯一性,消谐方程精确解存在范围等与消谐方程有关的问题也进行了深入探讨。用现有电力电子电路进行的验证试验表明,文中方法的容差性能好,消谐误差低,实用性强。
一类非自治动力系统超次谐周期解的不存在性  [PDF]
高经武,蔡中民,李庆士,武际可
力学学报 , 2004, DOI: 10.6052/0459-1879-2004-5-2003-523
Abstract: 在非线性动力系统的研究中,Melnikov函数被广泛地用来作为微扰哈密顿系统是否发生次谐或超次谐分岔乃至混沌的判据.但是在大多数情况下,经典的Melnikov方法往往只给出存在次谐周期解的结论.产生该结果的原因被归之为在经典的Melnikov方法中只采取了一阶近似,因而高阶Melnikov方法被发展用来判断超次谐周期解的存在性.本文对一类非自治微分动力系统进行了研究,证明了在这样一类系统中如果存在周期解则只可能是次谐周期解,超次谐周期解不可能存在,并进一步证明了在一类平面问题中所定义的旋转(R)型超次谐周期解同样不可能存在.作为该结论的一个应用,文中考察了几个典型的算例,结果表明现有的二阶Melnikov方法判断平面扰动系统是否存在超次谐周期解的结论是不恰当的,并提供了一个简单的几何上的解释.
含双时滞振动主动控制系统超谐共振及亚谐共振分析  [PDF]
孙清,张斌,刘正伟,伍晓红,薛晓敏
工程力学 , 2010,
Abstract: 该文采用增量谐波平衡法求解含双时滞振动主动控制系统的超谐共振和亚谐共振响应。讨论了使系统发生亚谐共振的激励频率取值范围,分析了时滞、反馈控制增益、激励幅值、非线性项系数等系统参数对系统超谐共振和亚谐共振响应的影响规律。结果表明:各参数对系统的超谐共振和亚谐共振响应有显著影响,发生亚谐共振的外激励频率的实际取值范围,受到各系统参数的影响。
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