Contactless electroreflectance spectroscopy of Ga(In)NAs/GaAs quantum well structures containing Sb atoms

Contactless electroreflectance (CER) spectroscopy has been applied to investigate the optical transitions in Ga(In)NAs/GaAs quantum well (QW) structures containing Sb atoms. The identification of the optical transitions has been carried out in accordance with theoretical calculations which have been performed within the framework of the effective mass approximation. Using this method, the bandgap discontinuity for GaN_0.027As_0.863Sb_0.11/GaAs, Ga_0.62In_0.38As_0.954N_0.026Sb_0.02/GaAs, and Ga_0.61In_0.39As_0.963N_0.017Sb_0.02/GaN_0.027As_0.973/GaAs QW structures has been determined. It has been found that the conduction-band offset is ∼50 and ∼80% for GaN_0.027As_0.863Sb_0.11/GaAs and Ga_0.62In_0.38As_0.954N_0.026Sb_0.02/GaAs QWs, respectively. It corresponds to 264 and 296 meV depth QW for electrons and heavy-holes in GaN_0.027As_0.863Sb_0.11/GaAs QW; and 520 and 146 meV depth QW for electrons and heavy-holes in Ga_0.62In_0.38As_0.954N_0.026Sb_0.02/GaAs QW. In the case of the Ga_0.61In_0.39As_0.963N_0.017Sb_0.02/GaN_0.027As_0.973/GaAs step-like QW structure it has been shown that the depth of electron and heavy-hole Ga_0.61In_0.39As_0.963N_0.017Sb_0.02/GaN_0.027As_0.973 QW is ∼144 and ∼127 meV, respectively.     

Enhancement of enzymatic digestibility of recycled newspaper by addition of surfactant in ammonia-hydrogen peroxide pretreatment

The effect of surfactant on enzymatic digestibility was investigated during the pretreatment stage. Newspaper was pretreated with an ammonia-hydrogen peroxide mixture on a shaking bath at 40°C and 130 strokes/min for 3 h. Two kinds of nonionic surfactants, NP series and Tween series, were utilized. The effect of hydrophile-lipophile balance (HLB) value of both series surfactants on digestibility was found to be negligible, even though de-inking efficiency was improved as HLB value was increased. The effect of surfactant loading on digestibility was small, below 0.5 wt%, and negligible above 0.5 wt% at 60 international filter paper units (IFPU). The percentage improvement in digestibility increased as enzyme loading decreased. Digestibility of NP-5-added sample relative to control sample, increased significantly at an enzyme loading <60 IFPU, i.e., 19 and 13% at 15 and 30 IFPU, respectively. Such an increase in digestibility was not explained clearly from the experimental results. It was also found that ink removal before enzymatic hydrolysis is very important to enhance digestibility.     

1.55 μm InGaAsP/InP tapered stripe superluminescent diodes with potential optical sensor system applications

We proposed a structure of a 1.55 μm InGaAsP/InP superluminescent diode (SLD) to suppress the lasing action and fabricated laterally tilted multi-quantum well planar buried heterostructure separate confinement heterostructure SLD by using MOCVD and LPE equipments. The fabricated SLD is laterally tilted by 15°. The output power of SLD was 11 mW for 200 mA under pulse driving. The full-width at half-maximum was 42 nm at 200 mA.     

Ultra LI-ideals in lattice implication algebras

We define an ultra LI-ideal of a lattice implication algebra and give equivalent conditions for an LI-ideal to be ultra. We show that every subset of a lattice implication algebra which has the finite additive property can be extended to an ultra LI-ideal.     

TEM investigation of the interaction between dislocation and nitride precipitates in deformed high manganese-chromium austenitic steels

The interaction between dislocations and nitride precipitates during high-temperature creep deformation of high manganese austenitic steels has been investigated by transmission electron microscopy. Most of the dislocations activated by applied stress were dissociated into Shockley partials. The fine TiN precipitates are pinning and/or incorporating the bow-type moving dislocations and they turned out to be more effective than the coarser TaN in disturbing the dislocation movement.     

Synthesis of Nonsymmetric Dibenzoyldihydromonobenzotetraazacyclo[14]annulenes as Transition Metal Hosts: X-ray Structure of 13,14-Benzo-3,10-di(p-chlorobenzoyl)-5, 8-dihydro-2,4,9,11-tetramethyl-1,5,8,12-tetraazacyclotetradeca-1,3,9,11-tetraene

In this paper, we evaluated the behavior of fibrous cerium (IV) acid phosphate (CeP) in insertion procedures involving a strong Lewis base (ethylamine) and a weak one (ɛ-caprolactam). In the former case, the procedure was performed by exposing a sample of CeP to a saturated amine atmosphere. Insertion was shown to be independent of the crystallinity of CeP, and the products showed strong host–guest interactions of the Coulombic type. Conversely, ɛ-caprolactam insertion was achieved by immersing CeP samples into its fused form. This process was dependent on the crystallinity of the inorganic solid, and host–guest interactions were characterized as involving hydrogen bonds.     

Case influence diagnostics in the kaplan-meier estimator and the log-rank test

One or few observations can be highly influential on the Kaplan-Meier estimator, and consequently on the log-rank test statistic in comparing two survival functions. In this paper we derive case influence diagnostics for the Kaplan-Meier estimator and the log-rank test. We note that diagnostics in this context is quite different from the regression context where observations are usually assumed to be independent. Simulation studies are done to present some guidelines to determine influential observations deserving special attention. Illustrative examples are also given.     

Enhancement of the enzymatic digestibility of waste newspaper using tween

Methods of increasing the enzymatic digestibility of waste newspaper by adding Tween (TW)-20 and 80 surfactants were investigated. Tween-series surfactants were selected because these surfactants increase cellulase activity during enzymatic hydrolysis and do not inhibit cell growth in downstream fermentation processes. When surfactant was used in a pretreatment, a benefic effect was expected in the enzymatic hydrolysis stage owing to surfactant carry-over from the pretreatment stage immediately upstream of the hydrolysis. However, because it was necessary to wash the pretreated substrate with water to remove inhibitors produced during pretreatment, no added benefit was obtained. When surfactant was used in the pretreatment only, it was found that it had a marked effect on digestibility and that this effect was higher at lower enzyme loadings. Also, TW-80 was found to be more effective than TW-20, and the addition of enzyme and TW-80 to substrate at the beginning of enzyme reaction was found to most effectively increase digestibility. When TW-80 was added into either the pretreatment stage or the hydrolysis stage the digestibilities of untreated sample increased by approx 40%, whereas an increase of only 45% was observed when TW-80 was added to both stages. These results show that the addition of surfactant to either the pretreatment or the enzymatic hydrolysis stage is sufficient to increase digestibility.     

Electrochemical preparation and spectroelectrochemical study of neptunium chloride complexes in LiCl–KCl eutectic melts

Lyoluminescence (LL) is a good technique for radiation dosimetry of high-energy radiations. Dosimetry of γ rays from ⁶⁰Co radioactive source has been done using MgB₄O₇:Mn²⁺ phosphor material. It was synthesized by simple solid state diffusion method. The material shows good linear LL response with the γ rays for the dose rage of 10 Gy–10 kGy. The studies have also been done for different particle sizes (250–45 µm) and particles having average size ~85 µm were found to be the most suitable for this dosimetry. Effect of solvent pH on LL and fading on storage has also been studied.