Experimental demonstration of a novel heterogeneously integrated III-V on Si microlaser

In this work we present the first experimental demonstration of a novel class of heterogeneously integrated III-V-on-silicon microlasers. We first show that by coupling a silicon cavity to a III-V wire, the interaction between the propagating mode in the III-V wire and the cavity mode in the silicon resonator results in high, narrow band reflection back into the III-V waveguide, forming a so-called resonant mirror. By combining two such mirrors and providing optical gain in the III-V wire in between these 2 mirrors, laser operation can be realized. We simulate the reflectivity spectrum of such a resonant mirror using 3D FDTD and discuss the results. We also present experimental results of the very first optically pumped heterogeneously integrated resonant mirror laser. The fabricated device measures 55 mu m by 2 mu m and shows single mode laser emission with a side-mode suppression ratio of 37 dB

Valence electronic structure of Mn in undoped and doped lanthanum manganites from relative K x-ray intensity studies

Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $\gamma$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of pure $Mn$. Comparison of the experimental data with the multiconfiguration Dirac-Fock (MCDF) effective atomic model calculations indicates reasonable agreement with the predictions of ionic model for the doped {manganites except} that the electron doped $La_{0.7}Ce_{0.3}MnO_{3}$ and hole doped $La_{0.7}Ca_{0.3}MnO_{3}$ compounds show some small deviations. The results of $MnO_{2}$ and $LaMnO_{3}$ deviate considerably from the predictions of the ionic model. Our measured $K\beta/K\alpha$ ratio of $Mn$ in $La_{0.7}Ca_{0.3}MnO_{3}$ cannot be explained as a linear superposition of $K\beta/K\alpha$ ratios of $Mn$ for the end members which is in contrast to the recent proposal by Tyson et al. from their $Mn$ $K\beta$ spectra.Comment: 14 pages, 4 figures. to appear in NIM-B.Please send an e-mail for figure

Void Formation Study of Flip Chip in Package Using No-Flow Underfill

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.DOI: 10.1109/TEPM.2008.2002951The advanced flip chip in package (FCIP) process using no-flow underfill material for high I/O density and fine-pitch interconnect applications presents challenges for an assembly process that must achieve high electrical interconnect yield and high reliability performance. With respect to high reliability, the voids formed in the underfill between solder bumps or inside the solder bumps during the no-flow underfill assembly process of FCIP devices have been typically considered one of the critical concerns affecting assembly yield and reliability performance. In this paper, the plausible causes of underfill void formation in FCIP using no-flow underfill were investigated through systematic experimentation with different types of test vehicles. For instance, the effects of process conditions, material properties, and chemical reaction between the solder bumps and no-flow underfill materials on the void formation behaviors were investigated in advanced FCIP assemblies. In this investigation, the chemical reaction between solder and underfill during the solder wetting and underfill cure process has been found to be one of the most significant factors for void formation in high I/O and fine-pitch FCIP assembly using no-flow underfill materials

Semantic Web: An Integrated Approach for Web Service Discovery, Selection and Composition

Web services are remote methods can be invoked through open standards such as Simple Object Access Protocols. The increasing web services in the repositories makes the selection process very complex. The same can be extended in forming the composition of web services. This research focuses on the semantic web service selection and composition through design and implementation of a framework. The proposed framework is an ontology based service selection approach and the selected services are participating in the composition process. This approach deals with semantic search, which uses Quality of services for service selection and composition. The entire framework is implemented with semantic web technology and the performance of the system is observed with domain specific ontologies

Lymphadenectomy in Management of Invasive Bladder Cancer

Radical cystectomy with pelvic lymphadenectomy represents the gold standard for treatment of muscle-invasive bladder cancer. Extent of the lymph node dissection and lymph node involvement during radical cystectomy are the most powerful prognostic factors associated with poor oncological outcome. However, the optimal boundaries of the lymph node dissection during a radical cystectomy are controversial. The published literature based mostly on retrospective studies suggests that increasing the number of nodes excised may have therapeutic and diagnostic benefits without significantly increasing the surgical morbidity. These conclusions are, however, influenced by selection and surgeon biases, inconsistencies in the quality of the surgery, and node count variability. In this paper, we establish the current understanding about the utility of lymphadenectomy during a radical cystectomy for muscle-invasive bladder cancer

IN VITRO STUDY OF ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES OF OXALIC ACID-DERIVED BIOACTIVE CHELATING AGENT

Objective: The aim of this study is to evaluate the biological potentials of sodium cadmium oxalate dihydrate complex prepared by a single diffusion method in the silica gel medium. Methods: The present complex was derived by the oxalic acid using a single diffusion method in gel medium and tested for single-crystal X-ray diffraction, ultraviolet-visible (UV) spectrum (190–500 mm), and solubility (distilled water at 20–29°C) studies. Antioxidant activity was determined by 2, 2-diphenyl-1-picrylhydrazyl assay, and antimicrobial activity was measured by agar well diffusion method. Results: The present chelating complex was successfully synthesized by gel technique. The solubility of sodium cadmium oxalate dihydrate was moderately good for deionized warm water. The UV spectral studies confirmed the chelating O-H, Na-O, and C-O bonds of the newly synthesized complex for the optical and biological properties. Conclusions: The metal-oxygen and oxygen-hydrogen bonds of the present newly synthesized sample much improved its optical, antimicrobial, and antioxidant activities and find its applications in the field of pharmaceutical and biomedical applications