Measurements of coupling and reflection characteristics of butt-joints in passive waveguide integrated laser diodes

Amplified spontaneous emission (ASE) spectra of passive waveguide integrated lasers have been studied to estimate the coupling efficiency and the reflectivity at the butt-joints between active and passive waveguides. A new method has been proposed for the analysis of ASE to extract the coupling efficiency and reflectivity at the butt-joints. This method was applied experimentally to estimate the coupling and reflection of the passive waveguide integrated lasers with different amounts of vertical misalignments of active and passive waveguides.     

Development of a momentum microscope for time resolved band structure imaging

We demonstrate the use of a novel design of a photoelectron microscope in combination to an imaging energy filter for momentum resolved photoelectron detection. Together with a time resolved imaging detector, it is possible to combine spatial, momentum, energy, and time resolution of photoelectrons within the same instrument. The time resolution of this type of energy analyzer can be reduced to below 100 ps. The complete ARUPS pattern of a Cu(111) sample excited with He I, is imaged in parallel and energy resolved up to the photoelectron emission horizon. Excited with a mercury light source (h nu=4.9 eV), the Shockley surface state at the energy threshold is clearly imaged in k-space. Electron-electron interactions are observed in momentum space as a correlation hole in two-electron photoemission. With the high transmission and the time resolution of this instrument, possible new measurements are discussed: Time and polarization resolved ARUPS measurements, probing change of bandstructure due to chemical reaction, growth of films, or phase transitions, e.g., melting or martensitic transformations.     

Mucoadhesive Phenolic Pectin Hydrogels for Saliva Substitute and Oral Patch

Oral disease is one of the most common conditions worldwide, negatively affecting general health, reducing the quality of life, and often developing into systemic illness. However, the design of therapeutic agents for oral diseases is challenging due to various unique features of the oral cavity, including its wet and dynamic environment and curved shape. Herein, the development of highly biocompatible mucoadhesive functional hydrogels for oral applications is reported, generated by introducing bio-inspired phenolic moieties into a pectin polymer. Pyrogallol-functionalized pectin (Pec-PG) can be crosslinked in situ via autoxidation without chemical agents and readily fabricated as various formulations. Sprayable Pec-PG hydrogel exhibits strong mucoadhesion and outstanding hydration ability ex vivo and in vivo, thus displaying significant potential as a novel saliva substitute for dry mouth. The authors further show that topical application of mucoadhesive Pec-PG patches pre-loaded with corticosteroid significantly promotes the repair of diabetic oral ulcer tissue via prolonged drug release, free radical scavenging, and physical barrier effects. Moreover, similar applications for oral ulcer treatment using a pectin hydrogel modified with catechol (Pec-CA), another phenolic moiety are demonstrated. Together, these findings suggest that mucoadhesive phenolic pectin derivatives can provide highly biocompatible, convenient, and effective hydrogel platforms for treating oral diseases.     

Template-directed synthesis of nitrogen- and sulfur-codoped carbon nanowire aerogels with enhanced electrocatalytic performance for oxygen reduction

Heteroatom doping,precise composition control,and rational morphology design are efficient strategies for producing novel nanocatalysts for the oxygen reduction reaction (ORR) in fuel cells.Herein,a cost-effective approach to synthesize nitrogen-and sulfur-codoped carbon nanowire aerogels using a hard templating method is proposed.The aerogels prepared using a combination of hydrothermal treatment and carbonization exhibit good catalytic activity for the ORR in alkaline solution.At the optimal annealing temperature and mass ratio between the nitrogen and sulfur precursors,the resultant aerogels show comparable electrocatalytic activity to that of a commercial Pt/C catalyst for the ORR.Importantly,the optimized catalyst shows much better long-term stability and satisfactory tolerance for the methanol crossover effect.These codoped aerogels are expected to have potential applications in fuel cells.     

A software-based sensor for combined sewer overflows

A new methodology for online estimation of excess flow from combined sewer overflow (CSO) structures based on simulation models is presented. If sufficient flow and water level data from the sewer system is available, no rainfall data are needed to run the model. An inverse rainfall-runoff model was developed to simulate net rainfall based on flow and water level data. Excess flow at all CSO structures in a catchment can then be simulated with a rainfall-runoff model. The method is applied to a case study and results show that the inverse rainfall-runoff model can be used instead of missing rain gauges. Online operation is ensured by software providing an interface to the SCADA-system of the operator and controlling the model. A water quality model could be included to simulate also pollutant concentrations in the excess flow.     

Comparisons of mathematics achievement of grade 8 students in the United States and the Russian Federation

Using the Mantel-Haenszel (MH) Procedure, we analyzed data for 7,087 American and 4,022 Russian Grade 8 students from the Third International Mathematics and Science Study (TIMSS) to compare mathematics achievement in the two countries on each of the 124 multiple-choice items. The results of the analyses indicate that the performance of the students on individual multiple-choice mathematics items vary by country. The results also suggest that the relationship between country and item performance differ as a function of content area. A total score of a country's achievement does not provide the whole picture of achievement dynamics; it averages out potentially important information on student achievement and the causes of their performance relative to other countries. The dynamics of achievement across countries will not be revealed unless the analyses are done at the item level.     

Quantifying ethanol content of beer using interpretive near-infrared spectroscopy

On the basis of absorption measurements in the near-infrared (NIR) spectral range, a new method for the quantification of the ethanol content of beer is presented. Instead of the multivariate calibration models most commonly employed in NIR spectroscopic works, we use interpretive difference spectroscopy: Two wavelengths are selected according to the assignment of the absorption bands of the main substances of content of beer in the NIR region, and the difference between the absorbances at these wavelengths is used for ethanol quantification. Absorption spectra of the dominating beer ingredients are discussed and the calibration procedure with ethanol/water mixtures is shown. Robustness against the carbohydrate content of beer samples was demonstrated by analyzing solutions of ethanol and maltose in water. Validation of the method was performed with various beer samples with an ethanol concentration range between 0.5 and 7.7 vol %. The pertinent advantage of the procedure developed in this work is the indication that the results are independent from seasonal variations of the ingredients, which is of high interest for products with natural ingredients such as beer.     

Historical view of the influences of measurement and reading theories on the assessment of reading

The purpose of this study is to briefly explore the interactions among measurement theories, reading theories, and measurement practices from an historical perspective. The assessment of reading provides a useful framework for examining how theories influence, and in some cases fail to influence, the practice of reading assessment as operationalized in reading tests. The first section describes a conceptual framework for examining the assessment of reading. Next I describe the major research traditions in measurement theory that have dominated measurement practice during the 20th century. In the next section I briefly introduce major reading theories. Next, I bring together the previous two sections in order to examine the adequacy of the proposed conceptual framework for examining the assessment of reading. This section includes criticism of measurement theory by selected reading theorists. It also provides a brief history of the use of Rasch measurement theory to calibrate reading tests. Finally, the main points of the study are summarized and discussed. It should be recognized that this study represents a preliminary analysis of these issues.     

Synthesis of SiC nanorods from bleached wood pulp

Unbleached and bleached soft wood pulps have been used as templates and carbon precursors to produce SiC nanorods. Hydrolyzed tetraethylorthosilicate (TEOS), silicic acid was infiltrated into the pulps followed by a carbothermal reduction to form SiC nanorods at 1400 °C in Ar. Residual carbon formed along with SiC was removed by gasification at 700 °C in air. The SiC materials prepared from unbleached pulp were non-uniform SiC with a thick SiO₂ coating, while the SiC nanorods prepared from the bleached pulp were uniform and straight with dimensions of 250 nm in diameter and 5.0 mm long. The formation of uniform camelback structure of SiC in the reaction between silica and bleached pulp is attributed to more silica deposited in the amorphous region of cellulose.     

Home environment and the competitiveness of highly accomplished individuals in four talent fields.

This study explores the relationship between home environment and the competitiveness of highly accomplished individuals in 4 different talent fields (world-class tennis players, Olympic swimmers, award-winning concert pianists, and eminent research mathematicians). A secondary analysis was made of interview protocols collected as a part of the Development of Talent Project (B. S. Bloom, 1985). Results indicate that individuals from home environments in which competitiveness is valued, modeled, and rewarded tend to be more competitive, r(30)?=?.68, p?