NIST Handbook of Mathematical Functions,edited by Frank W.J. Olver,Daniel W. Lozier,Ronald F. Boisvert,Charles W. Clark

A comparison is made between the competing processes of x-ray scattering and photoelectric absorption. The latter topic is then developed more fully, particular attention being paid to absorption fine-structure and its relevance to the study of the unoccupied energy levels available to electrons in solids. Electron wave scattering theories of metal fine-structure are outlined, together with the simultaneous plasmon emission concept for transition metals and the bound ejected electron theory for the solid halides of potassium.     

Zum Diskussionsbeitrag von W. Brauer

Ohne Zusammenfassung

---

c B.

     

Percy W. Bridgman's second century

Percy Williams Bridgman's impact on science began in 1909 with his first three experimental papers. These publications on high pressure calibration, techniques, and compressibility, together with the many articles that followed, established his influence on the course of modern high pressure research. Grounded in classical thermodynamics and practical mechanics, his developments showed how the variable of pressure leads to myriad transformations in materials. Studies carried out under a broader range of conditions now provide unprecedented insights into chemical and physical properties at multimegabar pressures and temperatures from millikelvins to thousands of degrees, where novel electronic, magnetic, and superconducting phases are now being discovered. With careful attention to experimental techniques and material performance, Bridgman extended the available pressure range that could be achieved in the laboratory with the development of new devices. We are now witness to continued refinement of static and dynamic compression methods and in situ measurement techniques, including the marriage of high pressure methods with large facilities such as synchrotron, neutron, and laser sources. Bridgman showed the broad range of implications of this work; the modern field of high pressure research now spans physics and chemistry, geosciences and planetary science, materials science and technology, and biology. Selected examples illustrate Bridgman's impact and legacy in this, his second century. For dense hydrogen, new insights have been obtained from high P–T measurements as well as studies of alloys and compounds of hydrogen, leading to the creation of new metallic and superconducting phases. Studies of other hydrogen-rich systems provide both tests of fundamental theory and potentially useful materials for hydrogen storage. High pressure studies of oxides have led to new ferroelectric and multiferroic materials and phases with remarkable properties that guide the design and fabrication of new devices. With the discovery of super-Earths outside our solar system, the high pressure properties of silicates, oxides, volatiles, and the full complement of planetary materials are now problems of cosmic importance well beyond the conditions found on and within the Earth. Developments in high pressure biology are addressing the question of the depth of the biosphere, the processes and reservoirs of carbon in our planet, and new insights into the origins of life as we know it, as well as the possibility of extraterrestrial life. Improved materials that can withstand high P–T conditions and other extreme environments include new forms of diamond, which are advancing experimental methods and finding numerous applications in advanced technology. These developments dovetail with synergetic advances in a broad spectrum of radiation techniques including coherent X-ray, intense neutron, and ultrabright laser sources.     

泡利的一个疏误

本文指出了泡利在推导匀速运动带电粒子所产生的电磁场时出现的一个概念性疏误，并予以分析纠正。     

质谱仪的发明者阿斯顿半

英国实验物理学家阿斯顿因发明质谱仪分离同位素而获得1922年诺贝尔化学奖.他只拥有学士学位,这在诺贝尔奖的获得者中是不多见的.他是怎样取得成功的,又为何能取得成功?是值得我们去探究的.文章着重介绍了阿斯顿的研究历程,并分析其成功经验,以为今天所倡导的创新研究提供借鉴.     

W.R. Grove and the fuel cell

Though known these days largely because he invented the fuel cell, Grove also had many other distinguished achievements to his credit. His monumental book On the Correlation of Physical Forces contained all the arguments that led to the enunciation of the first law of thermodynamics. He was also an extremely versatile natural philosopher who was, in addition, well versed in classical literature, particularly the works of the eminent scholars of ancient Greece and Rome. This article touches upon these qualities, but is predominantly concerned with the emergence and modern aspects of the H₂/O₂ fuel cell and its potential for the clean generation of energy.     

HPLC测定云厚朴中厚朴酚及和厚朴酚含量

建立了高效液相色谱同时测定云厚朴提取物中已知有效成分厚朴酚及和厚朴酚含量的方法.采用色谱柱Agilent SB-C18柱,以甲醇-0.1％冰乙酸(73∶27,V/V)为流动相,1.0mL/min,294nm,25℃的色谱条件.结果显示,厚朴酚及和厚朴酚两种化合物呈现出较好的回归方程和相关系数,相关系数达到0.9999.厚朴酚与和厚朴酚的平均回收率分别为98.498％、98.373％.本方法快速准确,精密度高,稳定性好,大大缩短了测定的时间,为云厚朴相关的质量控制与含量测定提供了重要的参考.     

Observation of surface modes in S.W.R.

We wish to report the unambiguous observation of surface modes in spin wave resonance in thin metal films. These surface modes, as predicted by Puszkarski are shown to be evident in both the parallel and perpendicular field configurations.