Solid state radioluminescent lighting

We have demonstrated novel types of tritium-powered, solid-phase radioluminescent (RL) light sources. These lights include: (1) all-organic formulations comprised of polystyrene and fluorescent organic dyes; (2) polydimethylsiloxane-based systems incorporating inorganic phosphors; and (3) inorganic aerogel-based systems doped with phosphors. Three principal design consideration for these new RL lights are described. These include: (1) incorporation of tritium into the solid matrix; (2) molecular engineering to maximize light-output efficiency; and (3) strategies for increasing longevity. The advanced RL lights, which are of interest due to potential advantages in efficiency, brightness and safety, are being developed for emergency lighting uses and for battery and lighting applications in remote locations.     

Solid state reactions of hexafluorosilicates

At beginning thermal decomposition K₂[SiF₆] loses SiF₄-planes from [SiF₆]^2?-octahedrons, which has been proved by x-ray-diffraction [1], [2]. Analogous disorder structures are supposed to be present with all solids having complex ions including carbonates, sulfates and others. The result is a high reactivity at this spots. Another reactive form in hexefluorosilicates is represented by mobile SiF-species, perhaps SiF₃⁺. The reactivity is shown by heterogenous reactions with CHCl₃ and by solid-solid reactions for instance with halides, oxides etc. As an example corundum (α-Al₂O₃) reacts at 600°C giving K₃ AlF₆ and KAlSiO₄ [3].     

Solid state reaction between dichromates and oxalates

The thermal investigation of the reaction taking place between dichromates and oxalates in the solid state has been done taking two systems of potassium dichromate-potassium oxalate and sodium dichromate-sodium oxalate. The techniques employed include thermogravimetry, differential thermal analysis, infrared spectroscopy and X-ray diffraction studies. The results indicate a stoichiometric reaction of dichromate and oxalate in 11 ratio to give the corresponding chromate as the sole product.

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Zusammenfassung Anhand der Systeme Kaliumdichromat-Kaliumoxalat bzw. Natriumdichromat-Natriumoxalat wurde eine thermische Untersuchung der Festkörperreaktion zwischen Dichromaten und Oxalaten durchgeführt. Dazu wurden thermogravimetrische, dififerentialthermoanalytische, IR-spektroskopische und Röntgendiffraktionsverfahren angewendet. Im Ergebnis zeigte sich eine stöchiometrische Reaktion von Dichromat und Oxalat im Verhältnis 11, die das entsprechende Chromat als einziges Produkt liefert.

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Solid state biosensors using thin-film electrodes

Solid-state technology was used to fabricate a new type of glucose sensor and a differential measurement system was incorporated with the sensor in order to suppress interfering signals. This glucose sensor was composed of film electrodes and an enzyme-immobilizing membrane. The hydrogen peroxide electrodes were fabricated by metallic film deposition. Glucose oxidase (GOD), an enzyme, was immobilized in photosensitive polyvinyl alcohol to enable the enzyme-immobilizing membrane to be formed by the usual photolithographic method. Two anodes and one common cathode were formed on a glass substrate. One of the anodes was coated with PVA containing active enzyme and the other with PVA containing deactivated enzyme. By setting up a differential output measurement system, it was possible to suppress the interfering signals that might be generated by some other reducing substances in a sample solution. With this measuring technique, the signal of ascorbic or uric acids up to 100 mg/dl was successfully cancelled. Glucose concentrations in the range 5 to 100 mg/dl could be detected by the present sensor.The fabrication processes of the present sensor were so compatible with IC technology that it should be possible to mass produce disposable glucose biosensors using IC fabrication techniques.     

Solid state synthesis of calcium borohydroxyapatite

Calcium borohydroxyapatite was synthesized by the solid-state reaction of colemanite (Ca₂B₆O₁₁·5H₂O) and diamonium hydrogenphosphate ((NH₄)₂HPO₄) at 1200 °C for 12 h. X-ray diffraction pattern showed only the formation of calcium borohydroxyapatite. The experimental analysis assigned the chemical formula as Ca₁₀[(PO₄)_5.80(BO₃)_0.20](OH)₂. It was indexed in the hexagonal system with the refined unit cell parameters of a = 9.557(3) Å, c = 6.926(8) Å and space group P6₃/m. The experimental results verified that if colemanite was used as a primary reactant for both calcium and boron source, the calcium borohydroxyapatite could be obtained.     

Solid state effects on core-hole spectra

Selective orbital coupling between levels of the ion and adjacent “neutral” molecules are shown to rationalize the spectral changes in the N 1s and O 1s XPS core-hole signals of p-nitroaniline on going from the vapor to condensed phase.     

Solid state environment effects on radioactivity

During investigations concerning technological applications, tritium was sorbed in small monocrystalline particles of titanium (φ ≈ 15 nm). When these preparations were heated to several hundred degrees centigrade, a strong decrease in the radioactivity of up to 40% was observed. The evaluation of several heating experiments done under quite different conditions rules out the possibility of trivial errors. Through evaluation of several gas-solid exchange and diffusion experiments done by others, in which radionuclides heavier than tritium (⁶³Ni, ⁶⁵Zn, ⁸⁵Sr) were used as tracers, it could be shown that a strong decrease in the radioactivity also exists for these nuclei. A first attempt is presented to explain these striking results by a nuclear-pair hypothesis. Several straightforward experiments are proposed for further exploration of the phenomenon.     

Solid state synthesis of homoleptic tetracyanamidoaluminates

Tetracyanamidoaluminates of the type LiM(2)[Al(CN(2))(4)] with M = Eu and Sr were prepared by solid-state metathesis reactions departing from EuF(2) (or SrF(2)), AlF(3), and Li(2)(CN(2)) in a 2 : 1 : 4 molar ratio. The ignition temperature of the exothermic formation of LiSr(2)[Al(CN(2))(4)] was obtained near 420 °C. An X-ray single-crystal structure refinement performed for LiEu(2)[Al(CN(2))(4)] revealed the presence of the novel homoleptic [Al(CN(2))(4)](5-) ion in the structure. The X-ray powder diffraction pattern of LiSr(2)[Al(CN(2))(4)] was indexed isotypically.     

Solid state reactivity and mechanisms in oxide systems

Starting from oxalate mixed crystals Ni_xMn_3?x(C₂O₄)₃·6H₂O thermal decomposition at reduced oxygen partial pressure (po₂= 2%) leads to the formation of NiMn₂O₄ (x = 1) at metastable conditions. Ni_1.5Mn_1.5O₄ (x = 1.5) existing in the metastable state only has been also prepared. The spinel compounds both are of the highly inversed type. Following a sol-gel preparation route Mg₂TiO₄ has been also found to be formed in the metastable state. Annealing results in decomposition of the compounds providing NiMnO₃ and 1/2α-Mn₂O₃ or NiMnO₃ only or MgTiO₃ and MgO, respectively. The reaction rates observed are lower for NiMn₂O₄ and Ni_1.5Mn_1.5O₄ than for Mg₂TiO₄ decomposition. The reverse reaction of NiMn₂O₄ formation above 730°C shows an endothermic enthalpy of +61 kJ·mol^?1. For Mg₂TiO₄ formation above 1050°C an endothermic enthalpy of +19.3 kJ·mol^?1 is found. The results are discussed in terms of structural features of the oxides.     

Solid state extrusion of thermoplastic elastomers 4

A solid state extrusion technique is applied as to produce oriented block copoly(ether ester) under various physical conditions. The morphology of the extruded samples is characterized in relation to the extrusion parameters and hard segment compositions of the polymer, using thermal analysis and X-ray methods. The lateral dimensions of the crystalline domains are found to be approximately 150 Å depending on the extrusion conditions. The statistics of the long range periodicity of the structure along the extrusion direction is in agreement with a one-dimensional two phase model, the crystalline portion of which does not vary much in thickness (35 – 45 Å). The unexpected increase in the long period and the thermal shrinkage suggest the existence of strained interlamellar amorphous chains (tie molecules). The observed variations in tensile properties are interpreted under the assumption that both the number of such tie molecules and their fully extended lengths are determined by the hard segment composition and the extrusion conditions. It is also argued that the increase in the glass transition temperature is not only a function of the composition of hard segments in the amorphous phase but also of the number of strained tie molecules.Herrn Dr. Dr. h. c. H. Hellmann zum 70. Geburtstag gewidmet.Part 3 cf. lit [11]     

Solid state phase transitions characterized by ESR and XAS

Measurements of the relaxation time, τ of electron systems to a disturbance, by two different spectroscopic methods are examined in detail, with the purpose to establish how the presence of fluctuations near a solid state phase transition are made evident in insulators, conductors and superconductors. The absolute temperature and the relaxation time determine the thermodynamic stability of the electronic system near a phase transition by the Uncertainty Principle. At a given temperature T, Landau and Lifshitz obtain the stability from the lower limit of the uncertainty in entropy in units of the Boltzmann constant, ΔS/k_B<<1 when T τ>>3.82 K ps. Magnetic resonance can measure τ>>10⁻¹⁰ s, when v=9 GHz. X-ray spectroscopy can measure τ<10⁻¹⁶s for hv>5 keV. The results extract information about phenomena that occur at the phase transition by following the evolution of spectral features versus T and crystal orientation. Electron spin resonance identifies the phase transition by the evolution of doublet, triplet and antiferromagnetic resonance, and energy loss. Analysis of the X-ray absorption near an element edge determines one, the relative valence: V(Cu in chains)−V(Cu in planes) ≈1 in YBa₂Cu₃O_7−δ, two, the appearance of allowed Cu K pre-edge quadrupole transitions at T_c, three, the enhancement of Ba L3,2 edge transitions by an order of magnitude, just above T_c, at a crystal orientation of the c-axis to the X-ray polarization vector of 8 π/18, and four, difference X-ray absorption spectra, relative to the transition temperature, identify the bonds as well as the atoms involved in the transition. The figure abstract shows the changes in electron density obtained by temperature difference X-ray absorption near the Y K-edge in YBa₂Cu₃O_7−δ below T_c.     

Solid state features of electrocrystallized tungstate films

X-ray diffraction, scanning electron microscopy, and infra-red spectroscopy are applied to study the evolution of films electrodeposited from acidic tungstate solutions. Structural inhomogeneity is found to be responsible for the difference in rechargeability of films of different thickness. Voltammetric responses demonstrate pronounced sensitivity to the nature of crystalline phases, thus throwing light on the defects of the lattice features of nonstoichiometric W(V)–W(VI) oxides. One crystalline phase observed in the films under study and attributed to the layered nonstoichiometric oxohydroxide was never reported for oxotungstate films fabricated by other techniques. This phase is believed to be special to electrocrystallized films and to keep some structural features of dissolved isopolytungstate molecular precursors.Dedicated to Prof. G.Horanyi with the highest respect to his experimental talents, remarkable papers and important contributions in various fields of modern electrochemistry.     

Solid state characterization of oligopyridine dicarboxamide helicates

A heptameric amide of 2,6-diaminopyridine and 2,6-pyridinedicarboxylic acid coordinates to Cu(II) to assemble into a double helical complex with a string of six shortly spaced Cu ions.     

含氮杂环化合物的固相光化学

本文研究了含氮杂环化合物同尿嘧啶醛、芳香醛酮、稠环化合物的固相光化学反应, 得到与液相光化学反应不同的结果。合成了十九种新化合物, 它们的结构由IR, ^1H NMR, MS和元素分析确定。用光谱方法表征了混晶的性质。X射线粉未衍射和差热分析表明, 吲哚同萘, 咔唑同蒽的混晶, 形成了分子化合物。对反应机理进行了初步探讨。     

微环境影响下的乙酰基香豆素与吲哚的固相光反应

本文研究了乙酰基香豆素及其衍生物与吲哚的混晶在微环境影响下的固相光反应，并用固体紫外光谱、固体荧光光谱和X-射线粉末衍射技术考察了混晶的特征。实验结果表明，3-乙酰基香豆素及其7-乙酰氧基、7-苯甲酰氧基、5,6-苯并和6-溴衍生物与吲哚的固相光反应分别得到1:2缩合产物1～5，而6-硝基衍生物与吲哚的固相光反应却得到开环脱羰加成产物6。通过IR、MS、^1H NMR和元素分析结果确定了这六个新产物的结构。固体光谱的测试结果表明，取代乙酰基香豆素与吲哚间混晶的形成，分子间存在相互作用，使分子所处的微环境条件发生了变化。     

Solid state structure and absolute configuration of filifolinol acetate

Careful reevaluation of the 1H and 13C NMR spectroscopic data of filifolinol acetate (4) led to the reassignment of the C-10 and C-11 signals, as well as the gem-dimethyl signals. Single crystal X-ray analysis provided an independent structural confirmation of 4, and comparison of the experimental vibrational circular dichroism spectrum with calculations performed using density functional theory provided the absolute configuration of this 3H-spiro-1-benzofuran-2,1'-cyclohexane and related molecules.     

Solid state interchain transesterification reactions in macromolecules

Interchain transesterification reactions (ITR) play an important role in high temperature synthesis of most linear polyesters. For example, polyethylene terephthalate (PET) is prepared commercially by heating and distillation of ethylene glycol from a glycol capped oligomer of PET. In this paper, the potential importance of ITR to effect a much wider range of reactions and process is examined. For example, the ability to control the sequence distribution in linear copolyesters is described. In particular, it is shown that one can induce a random sequence distribution in copolyesters by ITR or, conversely, develop an ordered sequence from a random copolyester again by ITR. In one family of liquid crystalline copolyesters an unusual competition between ordering and a thermal Fries rearrangement is described. A whole new family of crosslinked copolyesters has been developed based on this knowledge of ITR. Solid state processing of cured copolyesters into finished articles by ITR has also been demonstrated. These crosslinked copolyesters can be depolymerized back to the starting oligomers by a reverse ITR, providing for the first time a recyclable thermosetting resin.     

Solid state reaction between p-benzoquinone and dihydroxybenzene

Reaction kinetics of p-benzoquinone-p-dihydroxybenzene; p-benzoquinone-m-dihydroxybenzene and p-benzoquinone-o-dihydroxybenzene systems have been studied in the solid state using capillary, gravimetric, and dilatometric techniques. It is found that p-benzoquinone is the diffusing species. The diffusion occurs through surface migration and depends very much on the symmetry of the dihydroxybenzene molecules. Gravimetric studies indicate that cracks are formed in the product during reaction and that the reaction reaches completion. Dilatometric studies indicate that the reaction products are more compact and contraction in volume takes place during the course of reaction.