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1.
黎胜  于丹竹 《声学学报》2016,41(6):820-832
结构振动和声辐射的可控性和可观性指标对有源控制系统作动器/传感器的布置具有重要意义。对结构振动和声辐射的可控性和可观性指标进行了研究,提出了基于声压输出的振动模态可观性指标,在振动模态可控性和可观性指标的基础上,结合振动模态的声辐射效率,提出了结构声辐射的可控性和可观性指标和基于声压输出的可观性指标。以板结构为例,对结构振动和声辐射的可控性和可观性指标进行了计算分析和讨论,比较了基于声压输出和基于振动响应输出的振动模态可观性,重点研究了基于声压输出的振动模态可观性和结构振动及声辐射的可观性特点,最后对指标值在结构声有源控制中输入(输出)位置选择上的应用进行了讨论和比较,通过数值仿真对指标的有效性进行了验证。   相似文献   

2.
Abstract

Laser-induced breakdown spectroscopy (LIBS) is a sensitive optical technique capable of fast multi-elemental analysis of various kinds of materials (solid, liquids, and gases) and its applications are growing rapidly and continue to extend to include a broad variety of biological materials. Its application is suited particularly for urinary stones and gallstones bulk analysis and microanalysis because investigation of the spatial distribution of matrix and trace elements can help to explain their emergence and growth. Therefore, we review the application of LIBS for the analysis of different kinds of gallstones and urinary stones. In brief, we also describe the history, fundamentals, advantages, and disadvantages of LIBS and its potential for spectrochemical analysis of gallstones and kidney stones. We also emphasize the applications of different kinds of lasers in urology, particularly the laser ablation of gallstones and urinary stones and its recent progress. We also summarize and compare the analytical figures of merits of analytical techniques that are commonly used to characterize and/or analyze stones.  相似文献   

3.
This paper is a part of a review of recent (last 15 years) publications on experimental and theoretical methods and approaches for studying damage accumulation and fracture in crystalline solids. The first part of the review is devoted to the experimental studies that examine the physical mechanisms of microdamage nucleation and growth under various thermomechanical loads, physical and mechanical properties of materials, and the issues concerning the formation and growth of main cracks and transition to macrofracture. Particular attention is given to the studies of fatigue failure of various metals and alloys, particularly the features of micro- and macrodamage nucleation and growth in structures and specimens at different loading cycle parameters, and the effect of grain size, solid phase inclusions, grain boundaries, twins, etc. on damage evolution. A whole variety of modern approaches to the experimental study (including in situ studies) of specimen structure and stress-strain state is shown. Disadvantages of current experimental studies on damage and fracture are discussed, such as insufficient attention to the scale factor and determination of the representative volume for fracture analysis.  相似文献   

4.
为保证食品安全和消费者健康,无损检测技术广泛应用于果蔬质量检测中。光谱和图像技术可分别获取果蔬的内部和外部信息,成为质量检测的有效工具。为跟踪国内外研究进展并分析研究现况,从果蔬外部品质(尺寸、形状、表面缺陷、颜色、纹理等)、内部品质(内部缺陷、可溶性固形物、可滴定酸、水分、类胡萝卜素等单一品质及综合品质)、成熟度、货架期/贮藏期、产品溯源、生长监测、安全(农药残留、病虫和细菌侵染、转基因产品等)检测及光学系统设计等方面综述了光谱和成像技术的应用,分析了存在的图谱库不完善、解混处理算法复杂、高精度和便携式的光学系统开发力度不够、校正模型的影响因素复杂等问题。然后,归纳了发展趋势,指出了各组分可视化分析及交互作用机理解析、光与果蔬组织的交互作用机理分析和光学特性参数反演等光学特性分析、科学合理的综合评价体系的建立、新算法的应用和多种算法的联合使用、不同算法的可靠性和稳定性的提高、稳定和普适模型的建立、低成本和便携式等光学分析仪器的商品化开发和商业化应用等成为进一步探索的方向,为基于光谱和成像技术的果蔬质量检测发展提供了参考。  相似文献   

5.
水果和蔬菜的品质与安全是消费者最为关心的问题。传统的化学检测方法是一种费时费力的破坏性检测技术。随着成像和光谱技术的快速发展,高光谱成像技术已经广泛应用于农产品品质与安全的快速无损检测中。高光谱成像技术融合了传统的成像和光谱技术的优点,可以同时获取被检测物体的空间信息和光谱信息,因此该技术既可以像检测物体的外部品质,又可以像光谱技术一样检测物体的内部品质和品质安全。目前,已经有大量的基于高光谱成像技术检测水果和蔬菜品质与安全的研究性论文发表,为了深入了解高光谱成像技术的检测原理并跟踪国内外最新的研究进展,综述了高光谱成像技术在水果和蔬菜外部品质、内部品质和品质安全检测中的原理、发展和应用。另外,还简要介绍和讨论了高光谱成像系统的构成、常用的数据分析方法、发展趋势及面临的挑战。  相似文献   

6.
蒋国峰  周刚  宋一 《应用声学》2016,24(2):130-132
针对某机载惯导设备在外场的测试需求,设计了以PC-104为显示、控制和数据处理核心,并扩展程控数字表、多通道矩阵板,构建了原位测试仪的硬件电路。根据系统的功能要求和硬件电路特性,利用LabWindows/CVI虚拟仪器平台编制了人机接口界面和测试程序,控制硬件电路对某惯导设备的静态电阻和在线电压进行测试,并接收、分析、处理惯导原位工作时输出的实时串行数据,完成对惯导设备的静态测试和动态性能监测,实现对某机载惯导设备原位测试过程的自动化和测试结果管理的智能化,提高了测试效率和测试精度。该仪器通过改变或控制测试仪器的类别,可实现对多路信号多种性能指标的测试。应用结果表明,该测试仪具有性能稳定、操作简便、应用领域广、通用性强等特点。  相似文献   

7.
In this paper, we present the elementary principles of nonlinear quantum mechanics (NLQM), which is based on some problems in quantum mechanics. We investigate in detail the motion laws and some main properties of microscopic particles in nonlinear quantum systems using these elementary principles. Concretely speaking, we study in this paper the wave-particle duality of the solution of the nonlinear Schr?dinger equation, the stability of microscopic particles described by NLQM, invariances and conservation laws of motion of particles, the Hamiltonian principle of particle motion and corresponding Lagrangian and Hamilton equations, the classical rule of microscopic particle motion, the mechanism and rules of particle collision, the features of reflection and the transmission of particles at interfaces, and the uncertainty relation of particle motion as well as the eigenvalue and eigenequations of particles, and so on. We obtained the invariance and conservation laws of mass, energy and momentum and angular momentum for the microscopic particles, which are also some elementary and universal laws of matter in the NLQM and give further the methods and ways of solving the above questions. We also find that the laws of motion of microscopic particles in such a case are completely different from that in the linear quantum mechanics (LQM). They have a lot of new properties; for example, the particles possess the real wave-corpuscle duality, obey the classical rule of motion and conservation laws of energy, momentum and mass, satisfy minimum uncertainty relation, can be localized due to the nonlinear interaction, and its position and momentum can also be determined, etc. From these studies, we see clearly that rules and features of microscopic particle motion in NLQM is different from that in LQM. Therefore, the NLQM is a new physical theory, and a necessary result of the development of quantum mechanics and has a correct representation of describing microscopic particles in nonlinear systems, which can solve problems disputed for about a century by scientists in the LQM field. Hence, the NLQM built is very necessary and correct. The NLQM established can promote the development of physics and can enhance and raise the knowledge and recognition levels to the essences of microscopic matter. We can predict that nonlinear quantum mechanics has extensive applications in physics, chemistry, biology and polymers, etc.   相似文献   

8.
In this paper, we present the elementary principles of nonlinear quantum mechanics (NLQM), which is based on some problems in quantum mechanics. We investigate in detail the motion laws and some main properties of microscopic particles in nonlinear quantum systems using these elementary principles. Concretely speaking, we study in this paper the wave-particle duality of the solution of the nonlinear Schrödinger equation, the stability of microscopic particles described by NLQM, invariances and conservation laws of motion of particles, the Hamiltonian principle of particle motion and corresponding Lagrangian and Hamilton equations, the classical rule of microscopic particle motion, the mechanism and rules of particle collision, the features of reflection and the transmission of particles at interfaces, and the uncertainty relation of particle motion as well as the eigenvalue and eigenequations of particles, and so on. We obtained the invariance and conservation laws of mass, energy and momentum and angular momentum for the microscopic particles, which are also some elementary and universal laws of matter in the NLQM and give further the methods and ways of solving the above questions. We also find that the laws of motion of microscopic particles in such a case are completely different from that in the linear quantum mechanics (LQM). They have a lot of new properties; for example, the particles possess the real wave-corpuscle duality, obey the classical rule of motion and conservation laws of energy,momentum and mass, satisfy minimum uncertainty relation, can be localized due to the nonlinear interaction, and its position and momentum can also be determined, etc. From these studies, we see clearly that rules and features of microscopic particle motion in NLQM is different from that in LQM. Therefore, the NLQM is a new physical theory, and a necessary result of the development of quantum mechanics and has a correct representation of describing microscopic particles in nonlinear systems, which can solve problems disputed for about a century by scientists in the LQM field. Hence, the NLQM built is very necessary and correct. The NLQM established can promote the development of physics and can enhance and raise the knowledge and recognition levels to the essences of microscopic matter. We can predict that nonlinear quantum mechanics has extensive applications in physics, chemistry, biology and polymers, etc.  相似文献   

9.
This is the second paper on principles of demineralization. The initial paper is dedicated to the common definitions and the history of demineralization. In present work we review the principles and mechanisms of decalcification, i.e., removing the mineral Ca-containing compounds (phosphates and carbonates) from the organic matrix in its two main aspects: natural and artificial. Natural chemical erosion of biominerals (cavitation of biogenic calcareous substrata by bacteria, fungi, algae, foraminifera, sponges, polychaetes, and mollusks) is driven by production of mineral and organic acids, acidic polysaccharides, and enzymes (cabonic anhydrase, alkaline and phosphoprotein phosphataes, and H(+)-ATPase). Examples of artifical decalcification includes demineralization of bone, dentin and enamel, and skeletal formations of corals and crustacean. The mechanism and kinetics of Ca-containing biomineral dissolution is analyzed within the framework of (i) diffusion-reaction theory; (ii) surface-reaction controlled, morphology-based theories, and (iii) phenomenological surface coordination models. The application of surface complexation model for describing and predicting the effect of organic ligands on calcium and magnesium dissolution kinetics is also described. Use of the electron microscopy-based methods for observation and visualization of the decalcification phenomenon is discussed.  相似文献   

10.
Within the framework of generalized model of polypeptide chain, on the basis of the Hamiltonian of model of solvent, which interacts with a biopolymer in both competitive and noncompetitive ways, introduced earlier, analytical expressions are obtained and thermodynamic and other averaged parameters are calculated for both the repeating units of the biopolymer and the solvent molecules. Different cases of relations between parameters of competitive and non-competitive bonding are considered and processes of melting and alignment are studied. It is shown that these processes are accompanied by changes in solvation and redistribution of solvent molecules between the helical and coiled portions of the chain.  相似文献   

11.
不同比例有机无机肥配施土壤腐殖质组分的光谱学特征   总被引:3,自引:0,他引:3  
以16年长期定位试验为基础,探讨不同比例有机无机肥配施对土壤腐殖质特征的影响。通过分离纯化腐殖质中的胡敏酸(HA)和富里酸(FA)组分,并利用元素分析、红外光谱和核磁共振研究分析了F1(70%化肥+30%有机肥)、F2(50%有机肥+50%化肥)和F3(100%有机肥)三种施肥方式下的HA和FA含量及结构变化。结果表明,F3对于提升HA和FA含量的效果优于F1和F2处理,说明有机肥的施用量越高,土壤腐殖质组分的含量就越高。元素分析表明,不同配比的有机无机肥对HA和FA各元素含量及原子比影响不同。F2和F3都提高了HA的缩合度,降低了氧化度和极性,其中F3的效果更加明显;有机肥的施用还能促进HA中含氮化合物的形成,并且在F2中的效果最好;有机肥的施用同样提高了FA的缩合度而降低了氧化度和极性并促进了含氮化合物的形成,尤其在F2处理中尤为明显。腐殖质红外光谱分析表明,与F1相比,F2和F3提高了HA中脂肪族化合物、碳水化合物物质的含量,FA的羧基基团、脂肪基团含量也增加,且在F3处理中表现最为显著;F2处理则降低了HA中脂肪烃物质的含量,FA中的碳水化合物则达到最高。13C核磁共振波谱分析显示,在三种处理中,有机肥的施用提高了HA和FA的脂化度而降低其芳化度,其中F2处理中HA官能团变化更加显著,FA在F3处理中则变化更加明显。综上所述,有机肥显著提高了土壤腐殖质组分含量,并且提高了HA和FA的脂化度降低其芳化度,但是不同用量有机肥下HA和FA的形成机制不同。  相似文献   

12.
用于环境监测的生物传感技术   总被引:7,自引:1,他引:6  
论文评述了用于水、大气及其他环境监测的生物传感技术,展望了生物传感技术和传感器的前景。具体评述了水环境中BOD(生化需氧量)、酚、NO_3~-、有机磷盐的检测和赤潮的监测;大气环境中CO_2,SO_2和NO_x检测;残留有毒有害物、持久性有机污染物的检测,污染物毒性评价,细菌总数的测定等方面。  相似文献   

13.
We start by recalling some of the properties of hydrogen and present a summary of the phenomena caused by the reversible hydrogen sorption by metals and various forms of condensed carbon, at the surface and into the bulk, using molecular hydrogen gas, hydrogen plasma and electrochemically sorbed hydrogen. We then describe the use of hydrogen to modify the surface and bulk properties of various materials with a focus on applications and devices: electronic and optic phase transitions of thin films and related energy devices, surface polishing and cleaning, decrepitation and amorphization of intermetallics, growth of carbon nanostructures and electron emission from diamond-like and graphitic carbon, longrange perturbation of the electron distribution of graphitic structures by hydrogen defects, and the consequences for potential nanoelectronics. Received: 8 November 2000 / Accepted: 20 November 2000 / Published online: 9 February 2001  相似文献   

14.
钾硼胁迫对棉花功能叶物质成分影响的FTIR表征   总被引:3,自引:0,他引:3  
钾和硼均是植物必需的营养元素,对植物的生长、发育与生理代谢等起着重要作用。棉花对钾和硼都有较高的需求量,而棉花缺钾或缺硼时有发生。以鄂抗8号品种的棉花作为研究材料,利用傅里叶变换探讨钾硼胁迫对棉花功能叶片物质成分的影响。红外光谱(FTIR)对钾硼胁迫下棉花叶片的物质成分进行研究,分析钾硼缺乏情况下叶片红外光谱的差异。结果表明:(1)缺钾处理时,1 546.86, 1 438.85, 1 153.39和1 024.17 cm-1这4个特征峰消失,且其他特征峰的相对吸光度值与正常处理相比均减小,表明缺钾时棉花功能叶片蛋白质、纤维素、可溶性糖和核糖的结构发生变化且含量降低。(2)缺硼条件下,叶片的特征峰的相对吸光度均有所升高,因而,缺硼则导致蛋白质及可溶性糖、纤维素等碳水化合物等的运输受阻而在叶片中积累。(3)钾硼同时缺乏,棉花功能叶片特征峰的位置和相对吸收强度与正常处理相比有很大差异,表现为棉花功能叶片蛋白质和可溶性糖等碳水化合物的含量升高,而核酸和多糖分子等含量下降。因此缺钾导致棉花功能叶片蛋白质、纤维素、可溶性糖和核糖结构变化的含量降低;缺硼时蛋白质及可溶性糖、纤维素等碳水化合物等在叶片中积累;缺钾缺硼时蛋白质和可溶性糖等碳水化合物含量升高,而核酸和多糖分子等含量下降。  相似文献   

15.
AMolecularDynamicalTheoryofUltraweakBio-photonEmissionintheLivingSystemsandItsPropertes(1)¥PangXiaofeng(InternationalCentrefo...  相似文献   

16.
拉曼光谱对高地钩叶藤纤维S2层主要成分的预测   总被引:1,自引:0,他引:1  
棕榈藤(rattan)属于棕榈科(Palmae)省藤亚科藤类植物,是一种产于热带森林中,仅次于木材和竹材的、重要的非木材林产品,具有很高的经济价值和开发前景。全球棕榈藤总共有13个属660余种,其中我国自然分布有4属37种5变种,但有较高经济价值的不到30种。由于目前对棕榈藤的细胞结构,尤其是藤纤维的细胞壁结构知之甚少,严重限制了对棕榈藤材的研究和加工利用。因此,为构建棕榈藤材纤维细胞壁结构模型,以高地钩叶藤(Plectocomia himalayana Griff.)为研究对象,对其基部、 2 m处、中部和梢部四个部位分别截取试样、软化、聚乙二醇包埋、切片。切片在室温下经0.2 mol·L-1的硼氢化钠(NaBH4)溶液浸泡5~6 h后用蒸馏水洗净,利用LabRam XploRA显微共聚焦拉曼光谱仪,采用逐点扫描显微探针成像方法获取光谱数据集。将获得的光谱数据利用LabSpec5软件进行处理,从而得到藤茎不同部位藤皮、藤中、藤芯处纤维细胞次生壁中层(S2)主要成分,即纤维素、半纤维素、木质素相对含量,并就相对含量在径向、轴向变异进行了分析。结果表明,在径向上,高地钩叶藤藤皮处纤维细胞S2层纤维素与半纤维素相对含量最高,木质素相对含量最低;而藤芯处纤维细胞S2层纤维素与半纤维素相对含量最低,木质素相对含量最高;藤中处纤维素、半纤维素及木质素相对含量居中。在轴向上即不同藤龄处,藤皮纤维细胞S2层纤维素和半纤维素的相对含量在2 m处最大,木质素的相对含量在梢部最大;藤芯纤维细胞S2层纤维素、木质素、半纤维素的相对含量分别在中部、 2 m处、基部处最大。藤皮、藤芯与藤茎一样,纤维细胞S2层纤维素相对含量最小值在梢部,半纤维素和木质素相对含量均在中部最少。分析可知,棕榈藤藤茎不同部位,藤纤维细胞壁中层(S2)纤维素、半纤维素及木质素相对含量是不同的。  相似文献   

17.
介绍了基于几何莫尔条纹原理和衍射干涉原理的两种光栅精密位移测量系统及各自的特点。综述了国内外对光栅干涉式精密位移测量系统的研究进展,总结了系统存在的关键问题及发展趋势。光栅干涉式精密位移测量系统的优点是对环境要求小,测量分辨率和精度较高,结构紧凑,成本低。该系统需要解决的问题包括提高光栅以及光学元器件制造和安装精度;寻求一种更高精度的检测手段对光栅位移测量系统进行标定等。光栅干涉式精密位移测量系统的发展方向为更高测量分辨率和精度,大量程、多维度测量以及尺寸小巧。该系统在现代工业加工精密制造领域将具有更广阔的应用前景。  相似文献   

18.
The optical and physicochemical properties associated with the change (oxidation, thermolysis and photolysis), during the operation, of the spatial and electronic structures of the polyfunctional hydrocarbon compounds, oils, oil products, and N-, O-, and S-containing heteroaromatic compounds and additives, which comprise a variety of fuel and lubricant compositions involved in the structural and phase rearrangements, as well as in the formation of colloidal and micelle aggregates altering the structure with respect to their hydrocarbon, chemical, and fractional compositions, are investigated. The spectroscopic-luminescent properties of the compounds and their ion-radical forms were studied using optical and spectroscopic methods and quantum-chemical calculations when the excitation energy in the full spectra of singlet and triplet (for the ion, quartet and doublet) electronic excited states was deactivated. Intramolecular mechanisms of the hyperfine electron–nucleus interaction between the active groups of quasi-oscillators in the structure of polyfunctional compounds in the paramagnetic states of hydrocarbons, which form the electronic structure of the triplet–triplet transitions induced by pumping in the optical absorption spectra, are studied. It is shown that the mechanism of multistep ionization, fragmentation, and appearance of radicals and the electronic-vibrational mechanism of an increase in the vibration temperature up to T = 6000–7000 K are developed during the action of the ultraviolet (UV) pumping pulse of a nanosecond duration until the light emission, which gives rise to thermolysis and recombination that create the conditions for the combustion and explosion when the excitation energy is localized on a limited number of groups of quasi-oscillators in the structure.  相似文献   

19.
The present research focused on re-circulation and conversion of substance and energies for creating water environments of higher productivity and purification from the oceanic carbon and nitrogen cycle point of view. The application of distributed energies and integrated systems through the autonomous dispersion control of the environment is able to display the increase of the functions of living things and create the harmonized re-circulation of production and purification. As Japan is an island country, wave energy pumps and air-mixed jet pumps have been invented as distributed energy prime movers for these circulation systems. This paper summarizes our research and development programs and describes some current results of sea trials with prototypes.  相似文献   

20.
本文详细阐述了面发射分布反馈半导体激光器(SE-DFB-LD)的基本工作原理、结构设计及其工作性能,针对国内外研究最新进展与发展现状进行了总结和评述,并在此基础上,对面发射半导体激光器的研究工作和发展趋势做出了进一步的讨论和展望。随着面发射分布反馈半导体激光器各性能指标的不断优化提升和后期加工、装调技术的逐渐成熟,其将不断满足科学研究及工业、军事等实际应用领域对半导体激光器的需求,具有很大的发展潜力。  相似文献   

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