The optical properties and laser characteristics of Cr and Nd co-doped Y3Al5O12 ceramics

We have fabricated Cr³⁺ and Nd³⁺ co-doped YAG (Cr;Nd:YAG) ceramics, and investigated their optical properties and laser characteristics. The Cr;Nd:YAG has two broad absorption bands at around 440 nm (⁴A₂→⁴T₁) and 600 nm (⁴A₂→⁴T₂) respectively, caused by Cr³⁺ ions. In the case of pumping at 440 nm, the maximum effective lifetime of the Cr;Nd:YAG was 737 μs with a 0.1 at% Cr³⁺ and 1.0 at% Nd³⁺ co-doped YAG sample. Cr³⁺ ions take a role of an effective sensitizer to convert the UV light of flashlamp. For single-shot laser operation, a 10.4 J output energy at 1064 nm was obtained with 0.1 at% Cr³⁺ and 1.0 at% Nd³⁺ co-doped YAG ceramic rod with a laser efficiency of 4.9%. The laser efficiency was found to be more than twice that of a 1.0 at % Nd³⁺:YAG ceramic rod.     

Stress distribution in poly‐p‐phenylenebenzobisoxazole (PBO) fiber estimated from vibrational spectroscopic measurement under tension. II. Analysis of inhomogeneous stress distribution in PBO fiber

Fourier transform Raman spectra were measured for poly‐p‐phenylenebenzobisoxazole (PBO) fiber subjected to a tensile stress, and the Raman shift factor (the frequency shift caused by 1 GPa tensile stress) depended strongly on the sample‐preparation condition. To clarify the reasons of this dependency, a mechanical series parallel model was adopted that could successfully and quantitatively explain the observed Raman shift factors and gave a concreate heterogeneous stress distribution in the PBO fibers. As a result, a mechanical series model was reasonable for PBO fiber. Broadening of Raman bands, which was observed when the PBO fiber was tensioned, could also be interpreted on the basis of an idea of heterogeneous stress distribution. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1281–1287, 2002     

The pricing and optimal strategies of callable warrants

In this paper, we introduce a valuation model of callable warrants under a setting of the optimal stopping problem between the holder (investor) and the issuer (firm). A warrant is the right to purchase new shares at a predetermined price. When the new stocks are issued, the value of the stock is diluted. We consider the model taking the dilution into account. After identifying optimal policies for the issuer and the investor, we explore the analytical properties of the optimal exercise and call boundaries for the holder and the issuer, respectively. Furthermore, the value of such a callable warrant and the optimal critical prices are examined numerically using the binomial method.     

Photo‐capacitance spectroscopy investigation of deep‐level defects in AlGaN/GaN hetero‐structures with different current collapses

We have investigated electronic deep levels in two AlGaN/GaN hetero‐structures with different current collapses grown at 1150 and 1100 °C by a photo‐capacitance spectroscopy technique, using Schottky barrier diodes. Three specific deep levels located at ～2.07, ～2.80, and ～3.23 eV below the conduction band were found to be significantly enhanced for severe current collapse, being in reasonable agreement with photoluminescence and capacitance–voltage characteristics. These levels probably originate in Ga vacancies and residual C impurities and are probably responsible for the current collapse phenomena of the AlGaN/GaN hetero‐structures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

High-performance liquid chromatographic determination of boric acid and germanic acid with conductometric detection

Summary Boric and germanic acids were detected by a conductivity detector after ion-exclusion Chromatographic separation on a cation-exchange resin. Neither acid could be directly measured by a conductivity detector because they were very weak. However, use of eluents of polyol compounds permitted their determination by a conductivity detector. With 0.1 M of fructose as eluent, it was possible to detect 0.5 ppb of boric acid (as B) and 1.5 ppb of germanic acid (as Ge).

---

HPLC-Bestimmung von Borsäure und Germaniumsäure mit konduktometrischer Detection

Zusammenfassung Beide Säuren wurden mit Hilfe eines Leitfähigkeitsdetektors nach Trennung durch Ionenausschluß-Chromatographie an einem Kationenaustauscher analysiert. Eine direkte Messung war wegen der Schwäche der Säuren nicht möglich; daher wurde eine Elution mit Polyolen durchgeführt. Mit 0,1 M Fructoselösung als Eluens konnten noch 0,5 ppb Borsäure (als B) und 1,5 ppb Germaniumsäure (als Ge) nachgewiesen werden.

     

Influence of the Grain Boundaries on the Heat Transfer in Laser Ceramics

Grain boundaries play a key role in determining several key properties of polycrystalline laser ceramics. Heat transfer measurements at low temperature constitute a good tool to probe grain boundaries. We review the results of heat transfer measurements in polycrystalline Y₃Al₅O₁₂ garnets as well as Y₂O₃ and Lu₂O₃ sesquioxide materials obtained by self-energy-driven sintering of nano-particles. The average phonon mean free path in Y₃Al₅O₁₂ was found to be significantly larger than the average grain size and to scale with temperature as T ⁻² at low temperature. Existing models describing the interaction between phonons and grain boundaries are reviewed. Correct temperature dependence of the mean free path and order of magnitude of scattering rates were found by assuming the existence of a grain boundary layer having acoustic properties different from those of the bulk. A different temperature dependence of phonon mean free path was found for the sesquioxides and was ascribed to the stronger elastic anisotropy of these materials. The thermal resistance associated to the grain boundaries of laser ceramics was found to be lower than in other dense polycrystalline ceramic materials reported in the literature.     

Numerical analysis on blast furnace performance with novel feed material by multi-dimensional simulator based on multi-fluid theory

Multi-dimensional blast furnace operation simulator based on multi-fluid theory and reaction kinetics is applied to the novel operations of blast furnace. The effective use of carbon composite agglomerates (CCB) in blast furnace is expected to have several advantages to improve furnace efficiency. In this study, mathematical expression of reduction behavior of CCB was introduced into the blast furnace simulator and the effect of charging CCB to blast furnace and accompanying temperature lowering were numerically examined. The calculation results showed the increase in productivity and decrease in reducing agent rate with CCB charging while reduction of iron-bearing materials was retarded due to temperature decrease in stack region. Thermal analysis revealed that this improvement of heat efficiency is caused by the decrease in heat requirements for solution loss, sinter reduction and silicon transfer reactions, heat outflow by top gas and wall heat transfer.     

Application of partial-filling capillary electrophoresis using lectins and glycosidases for the characterization of oligosaccharides in a therapeutic antibody

Oligosaccharides in therapeutic recombinant antibodies play important roles in regulation of various biological functions. To monitor the glycosylation profiles of antibody pharmaceuticals in the manufacturing process, a highly sensitive and specific method is required. We extended partial-filling techniques using lectins and exoglycosidases in capillary electrophoresis for the characterization of 8-aminopylene-1,3,6-trisulfonic acid labeled N-linked oligosaccharides derived from the therapeutic antibody rituximab. In the lectin-filling method, Galb1–4GlcNAc-specific Erythrina cristagali agglutinin, a1, 6-linked Fuc-specific Aleuria aurantia lectin and Neu5Aca2–3Gal-specific Maackia amurensis lectin were used. The oligosaccharides migrated through the lectin plug during separation; the changes in separation profiles were observed according to the interaction with the lectins. The glycosidase-filling method allowed rapid digestion as suggested by the electropherograms. Partial-filling CE methods can avoid tedious hands-on procedures such as overnight incubation and optimization reaction condition with lectins and exoglycosidases. Combination of these partial-filling capillary electrophoresis methods makes the characterization of oligosaccharide profiles of therapeutic antibodies easier and faster.     

Phosphoproteome Profiling Using a Fluorescent Phosphosensor Dye in Two-Dimensional Polyacrylamide Gel Electrophoresis

We validated the novel PhosphoQUANTI SolidBlue Complex (PQSC) dye for the sensitive fluorescent detection of phosphorylated proteins in polyacrylamide- and two-dimensional gel electrophoresis (PAGE and 2DE, respectively). PQSC can detect as little as 15.6 ng of ß-casein, a pentaphosphorylated protein, and 61.3 ng of ovalbumin, a diphosphorylated protein. Fluorescence intensity correlates with the number of phosphorylated residues on the protein. To demonstrate the specificity of PQSC for phosphoproteins, enzymatically dephosphorylated lysates of Swiss 3T3 cells were separated in 2DE gels and stained by PQSC. The fluorescence signals in these gels were markedly reduced following dephosphorylation. When the phosphorylated proteins in Swiss 3T3 cell lysates were concentrated using a phosphoprotein enrichment column, the majority of phosphoproteins showed fluorescence signals in the pI 4–5 range. Finally, we performed phosphoproteome analysis to study differences in the protein phosphorylation profiles of proliferating and quiescent Swiss 3T3 cells. Over 135 discernible protein spots were detected, from which a selection of 15 spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS). The PQSC staining procedure for phosphoprotein detection is simple, reversible, and fully compatible with MALDI TOF-MS.