Ein bisher unveröffentlichter Brief von Rudolf Kohlrausch and Andreas v. Ettingshausen von 1854, das Kohlrausch-Weber-Experiment von 1854/55 und die Lichtgeschwindigkeit in Wilhelm Webers Elektrodynamik

The reason for this letter was a belated delivery of the sinuselectrometer to the Austrian mathematician and physicist A.v. Ettingshausen in Vienna. The instrument was designed by R. Kohlrausch and made by the mechanic of the university in Marburg. By means of ths instrument the relations of charges could be measured. At the end of the letter Kohlrausch reported on the experiment made together with Wilhelm Weber for the determination of the relation between the absolute electrostatic and electromagnetic measured charges. The result was the velocity of light, but not perceived as such by Weber and Kohlrausch. In 1857 G. R. Kirchhoff was the first to define the connection between C _w and C _l (\(c_w = \sqrt 2 \cdot c_L \)). for a better understanding the dimensions of the Triple-Systems (Dreiersysteme) are used in the article. A. v. Ettingshausen was in close contact with the university of Göttingen and published the results of C. F. Gauss' and Weber's research work in the Danubian monarchy at an early time. When in 1857 Kirchhoff presented his two important works on the undulatory motion of electricity in conductors to J. C. Poggendorff, the editor of the Annals of Physics and Chemistry—Kirchhoff's works contain a preliminary form of the telegraph-equations—it became apparent that W. Weber and R. Kohlrausch had almost brought about a similar work and had come to the same result as Kirchhoff. On account of Kohlrausch's death in 1858 W. Weber was forced to finish the work by himself and published it only 1864 entitled “Über elektrische Schwingungen”. 1861 Maxwell at once discerned the velocity of light in the result and was now able to develop his elctromagnetic theory of light.     

William Carrick: A Scots photographer in St Petersburg (1827˜1878)

Abstract

William Carrick, whose name now appears in the Bolshaya Sovietskaya Encyclopaedia as one of the founders of Russian photography, was born of Scottish parents in Edinburgh, on 31st December 1827. A few months later he was taken to Russia, which was to be his home for the rest of his life. His grandfather and father were timber merchants, and ran their business from Cronstadt, the port for St. Petersburg.     

Interfacial microstructure and hardness of nickel (Ni) nanoparticle-doped tin–silver–copper (Sn–Ag–Cu) solders on immersion silver (Ag)-plated copper (Cu) substrates

Sn–Ag–Cu composite solder has been prepared by adding Ni nanoparticles. Interfacial reactions, the morphology of the intermetallic compounds (IMC) that were formed, the hardness between the solder joints and the plain Cu/immersion Ag-plated Cu pads depending on the number of the reflow cycles and the aging time have all been investigated. A scallop-shaped Cu₆Sn₅ IMC layer that adhered to the substrate surface was formed at the interfaces of the plain Sn–Ag–Cu solder joints during the early reflow cycles. A very thin Cu₃Sn IMC layer was found between the Cu₆Sn₅ IMC layer and the substrates after a lengthy reflow cycle and solid-state aging process. However, after adding Ni nanoparticles, a scallop-shaped (Cu, Ni)–Sn IMC layer was clearly observed at both of the substrate surfaces, without any Cu₃Sn IMC layer formation. Needle-shaped Ag₃Sn and sphere-shaped Cu₆Sn₅ IMC particles were clearly observed in the β-Sn matrix in the solder-ball region of the plain Sn–Ag–Cu solder joints. Additional fine (Cu, Ni)-Sn IMC particles were found to be homogeneously distributed in the β-Sn matrix of the solder joints containing the Ni nanoparticles. The Sn–Ag–Cu–0.5Ni composite solder joints consistently displayed higher hardness values than the plain Sn–Ag–Cu solder joints for any specific number of reflow cycles–on both substrates–due to their well-controlled, fine network-type microstructures and the homogeneous distribution of fine (Cu, Ni)–Sn IMC particles, which acted as second-phase strengthening mechanisms. The hardness values of Sn–Ag–Cu and Sn–Ag–Cu–0.5Ni on the Cu substrates after one reflow cycle were about 15.1 and 16.6 Hv, respectively–and about 12.2 and 14.4 Hv after sixteen reflow cycles, respectively. However, the hardness values of the plain Sn–Ag–Cu solder joint and solder joint containing 0.5 wt% Ni nanoparticles after one reflow cycle on the immersion Ag plated Cu substrates were about 17.7 and 18.7 Hv, respectively, and about 13.2 and 15.3 Hv after sixteen reflow cycles, respectively.     

John Thomson (1837–1921)

Abstract

Abstract Thomson did some of his most important work in Asia but was not, of course, the first European photographer to travel there. Thus, Eliphalet Brown, Jr. had accompanied Commodore Perry's expedition to Asia in 1852–1854. His daguerreotypes were reproduced by means of woodcuts and lithographs in the official report of the expedition. A Narrative of the Expedition to the China Seas and Japan ¹. Felice Beato photographed the Crimean War of 1855 with James Robertson, continued eastward photographing India during the next five years, and then attached himself to the Anglo-French campaign against China. There he covered the capture of Fort Taku at Tiensin, and later the destruction of the Imperial Summer Palace north of Peking in October 1860. Thomson appeared on the site 10 years later. He photographed Fort Taku also, and noted that it ‘looked like a deserted mud quarry’².     

Ni–YSZ(111) solid–solid interfacial energy

Solid-state dewetting of continuous Ni films deposited on the (111) surface of yttrium stabilized zirconia (YSZ) was used to produce equilibrated Ni particles, and the solid–solid interface energy was determined using Winterbottom analysis. The ~150 nm thick Ni films were dewetted (annealed) at 1350 °C in Ar + H₂ (99.9999 %) at an oxygen partial pressure of 10^?20 atm for 6 h. Transmission electron microscopy of equilibrated particles was conducted, and two low-energy low-index orientation relationships were found: $ {\text{Ni[1}}\overline{ 1} 0 ] ( 1 1 1 )\left\| {{\text{YSZ[1}}\overline{ 1} 0 ]} \right. ( 1 1 1 ) $ and $ {\text{Ni[}}\overline{ 1} 1 0 ] ( 1 1 1 )\left\| {{\text{YSZ[1}}\overline{ 1} 0 ]} \right. ( 1 1 1 ) $ , and the interface energies were measured to be 1.8 ± 0.1 and 2.1 ± 0.1 J/m², respectively. A model including grain growth concurrent with dewetting is used to explain the formation of the higher energy orientation relationship.     

Influence of cerium oxide (CeO2) nanoparticles on the microstructure and hardness of tin–silver–copper (Sn–Ag–Cu) solders on silver (Ag) surface-finished copper (Cu) substrates

Nano-sized, non-reacting, non-coarsening CeO₂ particles with a density close to that of solder alloy were incorporated into Sn–3.0 wt%Ag–0.5 wt%Cu solder paste. The interfacial microstructure and hardness of Ag surface-finished Cu substrates were investigated, as a function of reaction time, at various temperatures. After the initial reaction, an island-shaped Cu₆Sn₅ intermetallic compound (IMC) layer was clearly observed at the interfaces of the Sn–Ag–Cu based solders/immersion Ag plated Cu substrates. However, after a prolonged reaction, a very thin, firmly adhering Cu₃Sn IMC layer was observed between the Cu₆Sn₅ IMC layer and the substrates. Rod-like Ag₃Sn IMC particles were also clearly observed at the interfaces. At the interfaces of the Sn–Ag–Cu based solder-Ag/Ni metallized Cu substrates, a (Cu, Ni)–Sn IMC layer was found. Rod-like Ag₃Sn and needle-shaped Cu₆Sn₅ IMC particles were also observed on the top surface of the (Cu, Ni)–Sn IMC layer. As the temperature and reaction time increased, so did the thickness of the IMC layers. In the solder ball region of both systems, a fine microstructure of Ag₃Sn, Cu₆Sn₅ IMC particles appeared in the β-Sn matrix. However, the growth behavior of the IMC layers of composite solder doped with CeO₂ nanoparticles was inhibited, due to an accumulation of surface-active CeO₂ nanoparticles at the grain boundary or in the IMC layers. In addition, the composite solder joint doped with CeO₂ nanoparticles had a higher hardness value than the plain Sn–Ag–Cu solder joints, due to a well-controlled fine microstructure and uniformly distributed CeO₂ nanoparticles. After 5 min of reaction on immersion Ag-plated Cu substrates at 250 °C, the micro-hardness values of the plain Sn–Ag–Cu solder joint and the composite solder joints containing 1 wt% of CeO₂ nanoparticles were approximately 16.6 and 18.6 Hv, respectively. However after 30 min of reaction, the hardness values were approximately 14.4 and 16.6 Hv, while the micro-hardness values of the plain Sn–Ag–Cu solder joints and the composite solder joints on Ag/Ni metallized Cu substrates after 5 min of reaction at 250 °C were approximately 15.9 and 17.4 Hv, respectively. After 30 min of reaction, values of approximately 14.4 and 15.5 Hv were recorded.     

Johann von Oppolzer (1808–1871) als Direktor der Medizinischen Klinik an der Universität Leipzig

Johann von Oppolzer (1808–1871) is known as one of the most influential representatives of the “Vienna School of Medicine”. However, little is known about Oppolzer’s short but significant work at the Leipzig Medical School (from October, 1848 to March, 1850). Being not only an excellent physician and an outstanding teacher in the field of internal medicine, he was very open-minded with respect to new developments in medicine. This is shown by documents found in the archives of the university of Leipzig. In 1849, in opposition to the other members of the medical faculty, Oppolzer voted in favour of the establishment of a chair of pathological anatomy and a chair of physiological chemistry at the Leipzig Medical School.      

Magnetic properties of Ni(II)–Mn(III) LDHs

The synthesis of Ni_1−xMn_x(OH)₂(CO₃)_x/2·nH₂O Layered Double Hydroxides (LDHs) for x = 0.2, 0.25 and 0.33, their characterisation by electron microscopy, X-ray diffraction and their magnetic properties are reported in this study. When x increases, the crystallinity of the nanoparticles is improved. The low temperature magnetic behaviour of these compounds is characteristic of the competition between in plane ferromagnetic and interlayer antiferromagnetic interactions. The ferromagnetism is due to in plane Ni cations interaction and decreases when manganese content increases (Tc decreases from 26 to 15 K when x increases from 0.2 to 0.33). It was found that the substitution of Ni by Mn ions favours the in plane antiferromagnetic order. This study demonstrates that magnetic interactions occur in LDH with non magnetic interlayer anions.     

Phase Relations in the Bi–(Pb)–Sr–Ca–Cu–Sc–O System

The phase relations in the Bi–(Pb)–Sr–Ca–Cu–Sc–O system were studied near Bi₂Sr₂CaCu₂O_{8 +} (Bi-2212) and (Bi,Pb)₂Sr₂Ca₂Cu₃O_{10 +} (Bi-2223) between 850 and 930°C. The introduction of Sc led to the formation of a new compound Sr₂ScBiO₆, which coexisted with Bi-2212 and Bi-2223. Using crystallization from a peritectic melt at different cooling rates, we obtained Bi-2212 matrix composites containing finely dispersed Sr_1.9Ca_0.1ScBiO₆inclusions, with T _cattaining 89 K. The T _cof the Bi-2223–Sr_1.9Ca_0.1ScBiO₆superconducting ceramic prepared by solid-state sintering of a Bi–(Pb)–Sr–Ca–Cu–Sc–O precursor was 108.5 K.     

Zhores Ivanovich Alferov (15.03.1930–01.03.2019)

Technical Physics Letters -     

Clarence Comyn Taylor (1830–79)

Abstract

The recent acquisition for the India Office collections of an album of early photographs of Nepal with captions signed simply C.C.T. led to research that has opened up a whole new area of photographic activity in Nepal and the Rajasthan area of India in 1862–64, and made possible the identification of the work of a fine photographer hitherto known only by name. Much, however, still remains to be done to expand on the preliminary survey of the work of Clarence Comyn Taylor presented here.¹