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The mutual annihilation of positive and negative electricity with an accompanying radiation of the equivalent electromagnetic energy has been invoked to account for stellar heat. Electrodynamics, without further generalization, has no way of admitting such annihilation accompanied by radiation. The generalizations necessary to provide logical meaning to the process are developed and discussed.In particular, it becomes necessary to extend the law of motion of electricity applicable to an electron as a whole, so as to apply also to that which remains of the electron when part of it is destroyed.  相似文献   

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【目的】 科学出版物的语义化过程中产生了大量的语义数据,分析这些语义数据的特征可以为语义出版实践提供参考和借鉴。【方法】 通过收集目前常用的典型科学出版物语义数据,多角度分析这些数据集的类型、组成要素、生成流程及其支持的应用系统功能,总结这些语义数据在开发、开放、发布中的共性。【结果】 目前主流的科学出版物语义数据集具有相似的数据开发与组织流程,偏向于自然科学领域,具有不同的组织粒度及应用特点。【结论】 科学出版物语义数据的生产与应用仍面临诸多挑战,需要在数据的规范使用、数据本身的质量以及基于这些数据的服务上予以重视。  相似文献   

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A general theory is developed for extended bandwidth operation of actively compensated finite gain amplifiers. Designs for three new circuits are given which implement the theory. These circuits employ only operational amplifiers and resistors and their gains depend only on their resistor ratios. Thus they are suitable for IC fabrication. Further in IC technology, the characteristics of the operational amplifiers as well as the resistor ratios track closely with each other with reference to temperature and aging. Thus the extended bandwidth operation of the amplifiers will be available over a wide temperature range as well as under varying aging conditions. Their characteristics can be tuned easily by trimming only two resistors. Applications of the new amplifiers have been considered in RC active filters as well as in inductance simulation schemes. Experimental results are given which closely agree with theoretical predictions. The results also indicate that substantial improvement in the usable bandwidth of the circuits employing the new amplifiers may be expected over those using the conventional design of finite gain amplifiers.  相似文献   

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Lu-Hf同位素体系及其岩石学应用   总被引:1,自引:0,他引:1       下载免费PDF全文
Lu-Hf是近几年来发展极为迅速的一门同位素定年和地球化学示踪技术.本文对这一同位素体系的发展历史、岩石学应用和存在的问题进行了全面的评述,对目前常见的样品溶解、质谱测定和激光剥蚀技术进行了全面介绍.虽然Lu-Hf同位素的发展历史可划分为TIMS、hot-SIMS、MC-ICPMS三个阶段,但MC-ICPMS仪器的出现,使Hf同位素发展速度明显加快.在介绍了Lu-Hf同位素的基本地球化学行为和基本原理之后,本文对这一同位素体系在岩石学上的应用作了全面的介绍,内容包括含石榴石和磷灰石岩石的同位素定年、早期大陆地壳形成与演化、不同端元地幔的性质及成因、岩浆作用过程的Hf同位素鉴别、区域地球动力学演化、变质作用过程中的Hf同位素变化等.最后对Lu的衰变常数、测定标准(JMC475溶液和固体锆石/斜锆石标准)的Hf同位素组成及Hf同位素的封闭温度等问题进行了讨论。  相似文献   

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The nature of the photosynthetic process is of great intrinsic interest, because it is fundamental to the growth of all green plants. This article reviews recent research in the mechanism of photosynthesis, with special reference to the ways in which it is regulated by prevailing conditions of light and temperature. From this, some important deductions are made about basic principles of breeding new strains of agricultural crops with enhanced potential for energy conversion.  相似文献   

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In this paper, we study the properties of Sumudu transform and relationship between Laplace and Sumudu transforms. Further, we also provide an example of the double Sumudu transform in order to solve the wave equation in one dimension which is having singularity at initial conditions.  相似文献   

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This paper reviews the design and fabrication of polydimethylsiloxane (PDMS)-based conducting composites and their applications in microfluidic chip fabrication. Owing to their good electrical conductivity and rubberlike elastic characteristics, these composites can be used variously in soft-touch electronic packaging, planar and three-dimensional electronic circuits, and in-chip electrodes. Several microfluidic components fabricated with PDMS-based composites have been introduced, including a microfluidic mixer, a microheater, a micropump, a microdroplet controller, as well as an all-in-one microfluidic chip.  相似文献   

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中国建设用地供需矛盾突出,已成为制约经济社会可持续发展的重要瓶颈.为破解土地供应相对不足与利用粗放浪费并存的矛盾,从地区差别化和行业差别化角度设计了行业地耗和建设用地集约化水平2个指标,用于产业准入和省级政府用地效率考核.以此为依据,合理确定新增建设用地的供应规模和结构,促使土地供应方式的转变.  相似文献   

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