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运用红外光谱法对铁皮石斛、金钗石斛、鼓槌石斛及其两种提取物所含化学成分的红外谱图整体变化规律进行解析和鉴定。采用傅里叶变换红外光谱对三种石斛及其提取物进行结构分析及鉴别。原药材粉末一维红外光谱图反映出铁皮石斛、金钗石斛和鼓槌石斛均含有2 920,2 852,1 737和1 509 cm-1附近的特征峰;1 000~1 200 cm-1波段内的特征峰,推测三种石斛均含有脂类、芳香类和淀粉类成分。二阶导数谱进一步佐证了以上结果。根据峰强来判断三种石斛所含化合物含量的差别,得出铁皮石斛和金钗石斛中的脂类和淀粉类成分含量较鼓槌石斛高,三者中以金钗石斛的脂类成分、铁皮石斛的多糖成分含量较高。三种石斛原药材粉末二阶导数光谱中观察到1 318和782 cm-1处草酸钙的吸收峰。三种石斛的两种提取物中的成分种类和含量与其原药材均有所不同,且不同种石斛之间也存在峰形、峰位、峰强的差别。在水提醇沉提取物、无水乙醇提取物中均发现油脂类、芳香类和多糖类成分的特征吸收峰。与标准品比对分析发现,金钗石斛和鼓槌石斛的多糖成分以淀粉为主,而铁皮石斛则以黏多糖为主;三种石斛无水乙醇提取物的红外光谱分析更清楚地发现脂类成分和芳香类成分的存在,且脂类成分以金钗石斛提取物的含量相对较高。芳香类成分以鼓槌石斛提取物的含量相对较高,红外光谱整体结构解析与鉴定方法能够递进式地验证铁皮石斛、金钗石斛和鼓槌石斛所含物质结构和量的差异,适合于不同种石斛的快速鉴别及质量评价与控制。 相似文献
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敲击乐器能够演奏出优美动听的音调旋律,其敲击工具与弦振动之间存在着规律性数理关系,不同形状的锤击工具,产生的音调具有明显差异.利用数理方法推导出敲击乐器采用不同锤击工具(平面锤、余弦凸面锤、细棒锤)产生的弦振动波动方程,通过计算软件Matlad)实现对弦振动复杂的波动方程数值求解,以直观的图像形式对弦振动进行了可视化仿真模拟. 相似文献
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敲击水杯音调变化的实验研究 总被引:1,自引:0,他引:1
敲击装水的杯子时音调会发生变化,装水量的多少与音调变化之间的关系已有说明和讨论,但是在对其原因的分析却存在分歧.本文利用虚拟仪器,通过一系列实验,应用具体数据进行了定性分析.实验表明敲击杯口和杯壁,音调变化不同;敲击杯壁不同位置,音调不变.笔者发现从实证的角度得出的结论与以往观点不能完全吻合,从而尝试从杯子的横向、纵向振动、液体的黏滞性对杯子振动的影响等方面来进行解释. 相似文献
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作为点火靶重要候选靶丸之一, 聚酰亚胺 (PI) 空心微球采用降解芯轴技术结合双单体气相沉积聚合法 (VDP) 制备. 在PI涂层过程中微球碰撞对表面质量影响较大, 为了减小碰撞提高表面质量, 选用筛网盘做样品盘, 激励方式由压电振动模式改为脉冲敲击模式进行对比. 实验数据表明微球运动过程中碰撞是引起表面质量变差的原因, 通过理论分析确认了筛网盘通过减少接触点可以减少微球与微球间、微球与样品盘间的碰撞, 并且将压电振动改为脉冲敲击模式可以减小微球碰撞次数. 脉冲敲击模式与压电振动模式相比, 其可控性、微球弹跳幅度、消除静电等方面均优于压电振动. 对于微球壁厚均匀性而言, 压电振动略好于脉冲敲击, 但相差较小. 单个微球的壁厚最大偏差前者为0.68 μm, 优于后者的0.73 μm; 单个微球壁厚平均值在同一批次内的最大起伏, 前者为0.26 μm, 优于后者0.57 μm. 白光干涉仪数据显示脉冲敲击起到了提高微球表面质量的作用, 其表面粗糙度Rq值由52–93 nm 减小到28–44 nm.
关键词:
脉冲敲击技术
聚酰亚胺靶丸
表面粗糙度
壁厚均匀性 相似文献
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传统的电脑键盘按键声信号采集方法是采用造价较高的低噪声马达以恒定的速度敲击键盘按键,通过传声器远距离采集键盘的按键声,该方法在自然环境下受环境噪声影响大,需在低噪声环境中进行,因此很难在工业上大规模使用。该文提出了一种新型的电脑键盘按键声信号采集方法,首先采用模拟信号驱动电磁铁模拟手指敲击键盘按键,然后通过缩小检测距离和设计隔声腔有效实现对环境噪声的隔离,最终使传声器有效采集键盘按键声信号。该方法有利于同类型设备在工业上的大规模使用,并可大幅度降低设备生产成本。 相似文献
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针对目前管道泄漏监测与安全预警技术的不足,提出了光纤布拉格光栅(FBG)振动传感的方法,搭建了管道振动信号实时监测系统,并在石油管道上进行了现场实验。通过对实验得到的时域信号进行初步分析,以及采用基于偏最小二乘判别分析法(PLSDA)的模式识别方法,可以对管道上的噪声、铁锹敲击、铁锤敲击、电钻钻孔信号进行有效区分,且信号识别正确率达到96%,得出FBG加速度振动传感器系统检测管道振动信号具有可行性的结论,为石油管道运输中存在的打孔盗油等破坏性行为的监测提供了可行方案,从而实现管道上振动信号的实时在线监测与科学管理。 相似文献
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Carl A. Batt Anna M. Waldron Natalie Broadwater 《Journal of nanoparticle research》2008,10(7):1141-1148
Nanotechnology will be an increasing part of the everyday lives of most people in the world. There is a general recognition
that few people understand the implications of the technology, the technology itself or even the definition of the word. This
lack of understanding stems from a lack of knowledge about science in general but more specifically difficulty in grasping
the size scale and symbolism of nanotechnology. A potential key to informing the general public is establishing the ability
to comprehend the scale of nanotechnology. Transitioning from the macro to the nanoscale seems to require an ability to comprehend
scales of one-billion. Scaling is a skill not common in most individuals and tests of their ability to extrapolate size based
upon scaling a common object demonstrates that most individuals cannot scale to the extent needed to make the transition to
nanoscale. Symbolism is another important vehicle to providing the general public with a basis to understand the concepts
of nanotechnology. With increasing age, individuals are able to draw representations of atomic scale objects, but these tend
to be iconic and the different representations not easily translated. Ball and stick models are most recognized by the public,
which provides an opportunity to present not only useful symbolism but also a reference point for the atomic scale. 相似文献
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The formation of ohmic contacts to n- and p-type ZnSe is reviewed. The mechanisms for forming reasonable low-resistance ohmic contacts to n-ZnSe are well understood. This results from the fact that the Fermi energy level of ZnSe is unpinned and metals with sufficiently large work functions can make contact to n-type material. However, the situation is reversed for p-ZnSe where a large band gap and large electron affinity make it impossible to find metals with sufficiently large work functions to create an ohmic contact. Instead, the use of HgSe to form low barrier height Schottky contacts and of ZnSe/ZnTe multiple quantum wells (MQWs) to form ohmic contacts is reviewed. Although the MQWs can be used to form ohmic contacts to p-ZnSe, they degrade at high temperatures and high current densities. This is reviewed and shown to be a serious problem for applications to laser diodes. 相似文献
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做实验的主人--写给学习物理实验的学生 总被引:3,自引:1,他引:2
在学习实验时应注意学习探索,本文从实验课上学什么,如何在探索中学习,如何进行误差分析,实验结果如何评价,怎样认识验证性实验,怎样理解实验的物理思想,怎样在实验过程中提出问题等几方面讨论了学生怎样做实验的主人. 相似文献
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Jürgen Mimkes 《Physica A》2010,389(8):1665-1676
Economic growth depends on capital and labor and two-dimensional calculus has been applied to economic theory. This leads to Riemann and Stokes integrals and to the first and second laws of production and growth. The mathematical structure is the same as in thermodynamics, economic properties may be related to physical terms: capital to energy, production to physical work, GDP per capita to temperature, production function to entropy. This is called econophysics. Production, trade and banking may be compared to motors, heat pumps or refrigerators. The Carnot process of the first law creates two levels in each system: cold and hot in physics; buyer and seller, investor and saver, rich and poor in economics. The efficiency rises with the income difference of rich and poor. The results of econophysics are compared to neoclassical theory. 相似文献
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M. Campbell J. A. Cosgrove C. A. Greated S. Jack D. Rockliff 《Optics & Laser Technology》2000,32(7-8):629-639
A review of laser Doppler anemometry (LDA) and particle image velocimetry (PIV) with their application to the measurement of sound is presented. The fundamental principles behind LDA and PIV are discussed and extended to the application of sound measurement. Special attention is paid to analysis of LDA signals including the Hilbert transform, which enables amplitude information to be obtained about various frequency components of a signal and wavelet analysis, which allows non-stationary signals to be accurately analysed. The influence of the refractive index variations in a medium due to a sound wave on the laser beams of an LDA signal is discussed. Attention is also paid to acoustic streaming which arises due to high-intensity sound, and PIV results are presented to demonstrate the effect. 相似文献
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EAST���弰��������ϵͳ��� 总被引:1,自引:1,他引:0
EAST运行中的温度改变会导致磁体及冷屏产生形变和位移。为了测量此位移的变化,利用一个延长臂,把位移转移到较易测量的位置,然后采用直滑式电位器把位移变化转换成电压变化并测量出其值,最终转换成位移的变化值。该测量系统解决了EAST装置中磁体和冷屏位移测量的难题。 相似文献
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Samuel A. Cushman 《Entropy (Basel, Switzerland)》2021,23(12)
Several methods have been recently proposed to calculate configurational entropy, based on Boltzmann entropy. Some of these methods appear to be fully thermodynamically consistent in their application to landscape patch mosaics, but none have been shown to be fully generalizable to all kinds of landscape patterns, such as point patterns, surfaces, and patch mosaics. The goal of this paper is to evaluate if the direct application of the Boltzmann relation is fully generalizable to surfaces, point patterns, and landscape mosaics. I simulated surfaces and point patterns with a fractal neutral model to control their degree of aggregation. I used spatial permutation analysis to produce distributions of microstates and fit functions to predict the distributions of microstates and the shape of the entropy function. The results confirmed that the direct application of the Boltzmann relation is generalizable across surfaces, point patterns, and landscape mosaics, providing a useful general approach to calculating landscape entropy. 相似文献
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The rangefinder described here is a self-contained instrument for hand-held operation by a diver for searching, tracking, navigation and surveying applications. It has four modes: 1 — to measure range to a passive target directly to ± 1 m; 2 — to measure range to a passive target indirectly to ± 0.1 m; 3 — to measure range to a coded transponder to either ± 1 m or ± 0.1 m; 4 — to indicate the presence of multiple targets downrange where each target occurs in a selected range interval. The pulse echo principle is employed, with pulses typically 250 μs long. The carrier frequency of 300 kHz can be altered easily if required by changing the transducer array. 相似文献