Splitting and storing excitons in strained coupled self-assembled quantum dots

We present a novel self-assembled quantum dot structure designed to spatially separate and store photo-generated electrons and holes in pairs of strain coupled quantum dots. The spatial separation of electron–hole pairs into quantum dots and strain-induced quantum dots has been investigated and verified by photoluminescence experiments. Results from time-resolved PL demonstrates that at low temperatures (3 K) the electron–hole pair can be stored for several seconds.     

Scanning electron microscopy and X-ray diffraction studies in the analysis of medical materials: Gore-Tex versus braided polyester tape for repair of the incompetent cervix

Cathodoluminescence in the scanning electron microscope and roentgenogram diffraction studies were applied to the analysis of two different medical materials used in cervical cerclage, the treatment of cervical incompetence. Braided polyester tape or Gore-Tex was used as suture material and was analyzed both before and after use in cerclage of the cervix. Results of SEM and X-ray diffraction studies showed distinct differences between the two materials, with the Gore-Tex demonstrating a superior morphological integrity and a decreased likelihood of phagocyte adhesion. These results correlated well with the clinical observations, which also showed Gore-Tex to be a superior medical material.     

数值序上鞅的若干有关问题

本文研究了连续时间的集值序上鞅．在一定的假设下我们证明了集值序上鞅有ｈ－Ｒｉｅｓｚ分解,然后证明了集值序上鞅的Ｄｏｏｂ－Ｍｅｙｅｒ分解定理．     

Real time magnetic field sensing and imaging using a single spin in diamond

The Zeeman splitting of a localized single spin can be used to construct a highly sensitive magnetometer offering almost atomic spatial resolution. While sub-μT sensitivity can be obtained in principle using pulsed techniques and long measurement times, a fast and easy method without laborious data postprocessing is desirable for a scanning-probe approach with high spatial resolution. In order to measure the resonance frequency in real time, we applied a field-frequency lock to the optically detected magnetic resonance signal of a single electron spin in a nanodiamond. We achieved a sampling rate of up to 100 readings per sec with a sensitivity of 6 μT/sqrt[Hz]. Images of the field distribution around a magnetic wire were acquired with ～30 μT resolution and 4096 submicron sized pixels in 10 min. The response of several spins was used to reconstruct the field orientation.     

High‐gain Zn1–xMgx O‐based ultraviolet photodetectors on Al2O3 and LiGaO2 substrates

We report the fabrication and characterization of highly responsive ZnMgO‐based ultraviolet (UV) photodetectors in the metal–semiconductor–metal (MSM) configuration for solar‐blind/visible‐blind optoelectronic application. MSM devices were fabricated from wurtzite Zn_1–xMg_x O/ZnO (x ～ 0.44) thin‐film heterostructures grown on sapphire (α‐Al₂O₃) substrates and w‐Zn_1–xMg_x O (x ～ 0.08), grown on nearly lattice‐matched lithium gallate (LiGaO₂) substrates, both by radio‐frequency plasma‐assisted molecular beam epitaxy (PAMBE). Thin film properties were studied by AFM, XRD, and optical transmission spectra, while MSM device performance was analyzed by spectral photoresponse and current–voltage techniques. Under biased conditions, α‐Al₂O₃ grown devices exhibit peak responsivity of ～7.6 A/W at 280 nm while LiGaO₂ grown samples demonstrate peak performance of ～119.3 A/W, albeit in the UV‐A regime (～324 nm). High photoconductive gains (76, 525) and spectral rejection ratios (～10³, ～10⁴) were obtained for devices grown on α‐Al₂O₃ and LiGaO₂, respectively. Exemplary device performance was ascribed to high material quality and in the case of lattice‐matched LiGaO₂ films, decreased photocarrier trapping probability, presumably due to low‐density of dislocation defects. To the best of our knowledge, these results represent the highest performing ZnO‐based photodetectors on LiGaO₂ yet fabricated, and demonstrate both the feasibility and substantial enhancement of photodetector device performance via growth on lattice‐matched substrates. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

A simple modification of the method of a single standard in spectrochemical analysis: Application to the determination of cadmium in high purity zinc

Summary A simple modification of the method of a single standard in spectrochemical analysis is proposed for routine use in analyses where synthetic standards or samples with additions cannot be conveniently prepared. The seven-step sector is used for measuring the spectral line intensities.The method was checked on known specimens and succesfully applied to the determination of cadmium in high purity zinc.

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Zusammenfassung Für Routineuntersuchungen in der spektrochemischen Analyse wird eine einfache Modifikation der Methode des Einzelstandards vorgeschlagen, wenn synthetische Standardproben oder Proben mit Zusätzen nicht leicht herstellbar sind. Für die Messung der Intensitäten der Spektrallinien wird ein siebenstufiger Sektor verwendet.Das Verfahren wurde an Proben bekannter Zusammensetzung geprüft und mit gutem Erfolg für die Bestimmung von Cadmium in hochreinem Zink angewendet.

     

Double bubbles in<Emphasis Type="Bold">S</Emphasis><Superscript>3</Superscript> and<Emphasis Type="Bold">H</Emphasis><Superscript>3</Superscript>

We prove the double bubble conjecture in the three-sphereS ³ and hyperbolic three-spaceH ³ in the cases where we can apply Hutchings theory: