Materials Literature
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Growth and sinking rates varied over a 61.4‐h period for semicontinuous cultures of the marine diatom Coscinodiscus concinnus grown at light intensities of 48 and 9 µ Einst m −2 s −1 on a 12L : 12D cycle. The time‐course of sinking rates showed cyclic fluctuations, with sinking rates generally decreasing during the da…
Sintering of a fine‐grained polycrystalline diamond compact with grains less than 1 μm in size was successfully carried out by making a laminate on a WC/Co powder compact under sintering conditions of 5.8 GPa and 1430° to 1480°C for 30 min, in which small amounts of poly(ethylene glycol) and fine powder of cubic boron…
The corrosion resistance of titanium exposed in nitric acid vapor is generally inferior to that immersed in nitric acid solution because of an inhibitor effect of elements dissolved by corrosion of titanium in the solution.A new type corrosion testing apparatus, which would not be influenced by such dissolved elements…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA novel polymerization behavior of spiroorthoester: an equilibrium polymerizationSatoyuki Chikaoka, Toshikazu Takata, and Takeshi EndoCite this: Macromolecules 1991, 24, 1, 331–332Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published…
The conventional three-dimensional alternating-direction implicit (ADI) method is modified by introducing an f factor (0 < f < 1). This modification allows the time step limit to be increased by a factor of 1/f with the solutions remaining stable and high accuracy being retained. This new method is tested for two diff…
The effect of additions of iron on the corrosion behaviour of a 70Cu–30Ni alloy in sea water was studied by electrochemical methods and corrosion tests. Iron additions of 0·5 and 2% increased the average corrosion resistance of the alloy. This beneficial effect is due to the formation of a layer containing a large qua…
The electrical, thermal, and multiple-stress (thermal and electrical) aging of cross-linked polyethylene (XLPE) cable models has been investigated in order to get information on aging effects and mechanisms. After endurance tests, XLPE cable models have been subjected to chemical, physical, electrical, and microstruct…
LiCaPO4 has been synthesized and characterized by combined X-ray and neutron powder diffraction. The phase adopts the trigonal space group P31c, a= 7.5247(1)Å, c= 9.9657(2)Å. The structure is composed of a three-dimensional framework of vertex-sharing LiO4 and PO4 tetrahedra enclosing five-sided channels running paral…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of the highly oxygenated ergostane type steroid (+)-withanolide EArturo Perez-Medrano and Paul A. GriecoCite this: J. Am. Chem. Soc. 1991, 113, 3, 1057–1059Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published inissue 1 Jan…
Most actinide nuclides decay by {alpha} emission with the formation of kinetically and electronically excited daughters. The behaviour of heavy recoil atoms can be inferred from the observation of rupture of equilibrium in the natural radioactive series, from hot atom chemistry and from computer simulation of collisio…
Contrary to previous reports sapphyrin does react with uranyl cation to give a stable complex, which is no longer aromatic, having undergone attack by methoxide to give a new neutral complex; the synthesis, characterisation and X-ray structure of the new compound are described.
Glycosides are the bioactive components of many famous Chinese medicines. Here reported are some bioactive glycosides we discovered from Chinese medicines in recent years. (1) Phenolic glycosides from Chinese medicines: Gastrodia elata, Aconitum austroyunanense and Helicia erratica, three bioactive phenolic glycosides…
Differential scanning calorimetry has been used to investigate the melting behaviour of mixtures of poly(ethylene oxide) and deuterium oxide. The phase diagram shows that a eutectic mixture is formed with a weight fraction of D2O of 0.57 and a melting point of 264 K. A change in the curvature of the polymer liquidus c…
シリカ,アルミナ,シリカ・アルミナの粉体ディスクを773～1773Kで大気中焼成し,それらの表面のXPS分析を行った.Si2p,Al2p及びO1sの束縛エネルギーはすべて表面組成に依存して連続的に変化した.同表面上の不純物ナトリウムも同様の挙動を示した.焼成温度が高いほどスペクトルの半値幅が小さくなった理由は結晶子径のサイズ効果に帰せられた.又,結晶化に伴って不純物元素の表面濃集,すなわち不純物の表面偏析が観測された.アルミナを例に,シリコンとナトリウムの表面偏析と固体酸性,塩基性及び触媒反応活性との間に見いだされた相関性を示す.
The reaction of Me(hexynyl)CuLi with (Me3Si)2 NCH2-CC-CO2Et followed by treatment with a diacid dichloride gave a facile access to meta-dipyrrolyl benzene or 2,6-dipyrrolyl pyridine derivatives, which were cyclised to tetrapyrrolic macrocycles 7 and 9; further reactions with Pd(acac)2 or Ni(acac)2 led to bimetallic co…
Solution annealed type 316L austenitic stainless steels modified with IV or V group elements were electron irradiated up to a dose of 10.8 dpa at temperatures of 623 to 843 K in an HVEM. X-ray diffraction analysis was also performed to determine the quantitative size factors of the additional elements in the 316L stee…
3,3′,5,5′-Tetra-tert-butyl-p-terphenoquinone 5, the first terphenoquinone, has been obtained as metallic blue–green crystals showing anisotropic semiconductivity; the crystal structure of 5 shows that the nearly-planar molecules form slipped stacks along the needle axis.
Notch sensitivity has been connected with the presence of a film-like s-phase morphology in the grain boundaries of cast test bars of Alloy 718 of a problem material in which premature fracture occurred during testing of smooth stress rupture bars at 650 "C. A heat treatment designed to produce a plate-like S-phase mo…
The time and frequency response of current and potential transformers (CTs and PTs) operating under fundamental frequency conditions are well known. However, in the presence of harmonic frequencies, these transformers can exhibit significant errors. The authors present CT and PT comprehensive frequency domain equivale…
An analysis using the Cambridge Database of 926 structures in the short-axis range up to 8.0 Å, containing divalent sulphur, Y—S—Z, shows that 77 have short axes less than 4.5 Å and are distinguished by a strongly directional pattern of sulphur–heteroatom interactions.