Deep Level in Heavily Zn-doped InP Layers Implanted with Ti and Ti/P

We have investigated deep level peaks observed in the photoluminescence spectrum of heavily Zn-doped InP layers grown by metalorganic chemical vapor deposition at energies centered at 0.89 and 0.94 eV. These peaks are enhanced when the samples are implanted with Ti. When P is co-implanted, however, the intensity of these peaks decrease, and at an increased dosage, the peaks disappear from the spectrum. The peaks are, therefore, dependent on the phosphorus vacancy produced by the excessive Zn doping or the implant damage. Hall measurement data show that the Ti/P-implanted p-type InP layer is converted to n type with its sheet resistance decreasing and the donor activation of Ti increasing for higher P co-implant dose. In addition, the photoluminescence intensity of the deep level peaks is highly correlated with the sheet resistance.This work was financially supported in part by KOSEF through OERC Grant No. 97K3-0809-02-06-1 and by the Ministry of Education of Korea through Grant No. ISRC-97- E-3205

Low Temperature Photoluminescence Characteristics of Zn-doped InP Grown by Metalorganic Chemical Vapor Deposition

Zn-doped InP layers were obtained by two different doping techniques: in situ doping by low pressure metalorganic chemical vapor deposition, and thermal diffusion from a Zn-containing film. Their low temperature photoluminescence ~PL! characteristics were studied, and compared. In Zn-diffused InP, the deep donor to acceptor transition was the most dominant transition and other transitions such as the band edge transition and the band to band or shallow donor to acceptor transition were not observed at the excitation power of 10 mW. On the other hand, well resolved band edge peaks and the band or shallow donor to acceptor transition peak were observed for in situ Zn doped InP, implying that less interstitial Zn atoms were generated during in situ doping. Saturation of the hole concentration at 1.531018 cm3 was observed in in situ Zn doped InP, and the changes in PL characteristics at the saturation level were extensively studied. Two new deep bands at 0.88–1.0 eV and 1.21–1.27 eV were observed, and the intensity of the lower energy band increased with diethylzinc flow rate. The lower energy band was observed even at room temperature, and it is presumed to be related with the saturation of hole concentration.This work was supported by the Ministry of Education through the Interuniversity Semiconductor Research Center ~ISRC 94-E-3142! and Korea Science and Engineering Foundation ~KOSEF 93-01-00-17!. One of the authors ~S.J.K.! would like to acknowledge the support by the Ministry of Education through the Interuniversity Semiconductor Research Center ~ISRC 97-E-3205!

Differential Relationship between Metabolic Syndrome Score and Severity of Coronary Atherosclerosis as Assessed by Angiography in a Non-Diabetic and Diabetic Korean Population

Whether the metabolic syndrome (MetS) has prognostic value for coronary artery disease (CAD) beyond its individual components is controversial. We compared the relationship between the number of MetS components and CAD severity as assessed by angiography in non-diabetic and diabetic subjects. We consecutively enrolled 527 patients who underwent their first coronary angiography. Patients were divided into four groups according to the number of MetS components: 0/1, 2, 3, and 4/5. A coronary atherosclerosis score was used to quantify the extent of atherosclerotic involvement. The relationship between the MetS score and angiographic CAD severity or clinical presentation was compared between non-diabetic and diabetic subjects. Individuals with the MetS (n = 327) had a higher prevalence of CAD (60% vs 32%, P < 0.001), multi-vessel disease (34% vs 16%, P < 0.001), and acute coronary syndromes (49% vs 26%, P < 0.001) than those without the MetS. In the non-diabetic group, atherosclerosis score increased with the MetS score (1.0 ± 2.1, 2.0 ± 2.9, 2.8 ± 2.9, and 3.6 ± 3.9, P < 0.001) whereas there was no significant difference in the diabetic group (0.5 ± 1.0, 5.2 ± 4.7, 4.2 ± 2.9, and 4.4 ± 3.5, P = 0.102). The MetS score is related to CAD severity in non-diabetic patients but the association between the MetS score and angiographic CAD severity may be obscured in the presence of diabetes

Crosstalk between Nuclear Factor I-C and Transforming Growth Factor-β1 Signaling Regulates Odontoblast Differentiation and Homeostasis

Transforming growth factor-β1 (TGF-β1) signaling plays a key role in vertebrate development, homeostasis, and disease. Nuclear factor I-C (NFI-C) has been implicated in TGF-β1 signaling, extracellular matrix gene transcription, and tooth root development. However, the functional relationship between NFI-C and TGF-β1 signaling remains uncharacterized. The purpose of this study was to identify the molecular interactions between NFI-C and TGF-β1 signaling in mouse odontoblasts. Real-time polymerase chain reaction and western analysis demonstrated that NFI-C expression levels were inversely proportional to levels of TGF-β1 signaling molecules during in vitro odontoblast differentiation. Western blot and immunofluorescence results showed that NFI-C was significantly degraded after TGF-β1 addition in odontoblasts, and the formation of the Smad3 complex was essential for NFI-C degradation. Additionally, ubiquitination assay results showed that Smurf1 and Smurf2 induced NFI-C degradation and polyubiquitination in a TGF-β1-dependent manner. Both kinase and in vitro binding assays revealed that the interaction between NFI-C and Smurf1/Smurf2 requires the activation of the mitogen-activated protein kinase pathway by TGF-β1. Moreover, degradation of NFI-C induced by TGF-β1 occurred generally in cell types other than odontoblasts in normal human breast epithelial cells. In contrast, NFI-C induced dephosphorylation of p-Smad2/3. These results show that crosstalk between NFI-C and TGF-β1 signaling regulates cell differentiation and homeostatic processes in odontoblasts, which might constitute a common cellular mechanism

VDR-AM: View-Dependent Representation of Articulated Models

We present a novel, View-Dependent Representation of Articulated Models (VDR-AM), and show its main benefits in the context of view-dependent rendering integrated with occlusion culling for large-scale crowd scenes. In order to provide varying resolutions on each animated, articulated model, we propose to use a cluster hierarchy in the VDR-AM for an articulated model. The cluster hierarchy serves as a dual representation for both view-dependent rendering and occlusion culling. For a high-performance view-dependent rendering and occlusion culling, we construct each cluster of the cluster hierarchy to contain a spatially coherent portion of the mesh that also has similar simplification errors. To achieve our goal, we present an error-aware clustering method for articulated models. We also identify a subset of animation poses that well represents the original pose data and perform the well-known quadrics-based simplification to efficiently compute our representation, while achieving a high quality simplification. At runtime, we choose a LOD cut from the cluster hierarchy given a user specified error bound in the screen space and render all the visible clusters in the LOD cut. We implement our method in GPU and achieve interactive performance (e.g., 40 frames per second) for large-scale crowd scenes that consist up to thousands of articulated models and 242 M triangles, without noticeable visual artifacts

Replication of surfaces of natural leaves for enhanced micro-scale tribological property

In this paper, we report on the replication of surfaces of Lotus and Colocasia leaves onto thin polymeric films using a capillarity-directed soft lithographic technique. The replication was carried out on poly(methyl methacrylate) (PMMA) film spin coated on silicon wafer using poly (dimethyl siloxane) (PDMS) molds. The function properties of the replicated surfaces were investigated at micro-scale in comparison with those of PMMA thin film and uncoated silicon wafer. The coefficients of friction of the replicated surfaces were almost five times lower than those of the PMMA thin film and four times lower than those of the uncoated silicon wafer. The superior micro-tribological properties of the replicated surfaces could be attributed to the reduced real area of contact projected by the surfaces. (C) 2006 Elsevier B.V. All rights reservedclose435

Analysis of failure of C-V characteristics of MIS structure with SiO2 passivation layer deposited on InSb substrate via Raman spectroscopy

The effect of interfacial phases on the electrical properties of Au/Ti/SiO2/InSb metal-insulator (oxide)-semiconductor (MIS or MOS) structures was investigated by capacitance-voltage (C-V) measurements. With increasing the deposition temperature of silicon oxide from 100 to 350°C using PECVD, the change in the interfacial phases between SiO2 and InSb were analyzed by resonant Raman spectroscopy to verify the relation between the breakdown of C-V characteristics and the change of interfacial phases. The shape of C-V characteristics was dramatically changed when the deposition temperature was above 300°C. The C-V measurements and Raman spectra represented that elemental Sb accumulation resulted from the chemical reaction of Sb oxide with InSb substrate was responsible for the failure in the C-V characteristics of MIS structure. Copyright © 2014 Materials Research Society.N