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981.
A high-density wavelength division demultiplexer (DEMUX) capable of demultiplexing eight-channel 200-GHz optically spaced signals into a 62.5-microm multimode-fiber array is reported. The wavelength range of operation is from 1549.32 to 1560.61 nm within the International Telecommunication Union grid. The measured wavelength accuracy is within 0.04 nm. The mean insertion loss of this DEMUX is 1.95 dB. Thermal analysis and temperature testing results are reported. The temperature test cycling from 20 degrees C to 60 degrees C indicates that the wavelength thermal drift is less than 0.8 pm/degrees C. Adjacent cross talk is measured to be better than -45 dB. The measured data transmission bit rate of this device is higher than 3.5 Gb/s. 相似文献
982.
Helm PA Diamond ML Semkin R Strachan WM Teixeira C Gregor D 《Environmental science & technology》2002,36(5):996-1003
Data collected over a 3-year study of a high arctic watershed and lake are used to understand the fate of organochlorine compounds (OCs) and form the basis of a mass balance contaminant fate model. The model uses the fugacity/aquivalence approach to describe OC dynamics between air, stream inflows and outflow, the water column, and surficial sediments. The steady-state model results indicate that stream inflows contributed from 96 to >99% of total chemical loadings, but 57-98% of total loadings were lost from the lake via the outlet, the percentage of which is controlled by the hydrologic regime of the high arctic lake. Conversely, only 0.4-3.4% of loadings were retained within the sediments due to the high export rate, minimal scavenging from the water column and low organic carbon fraction of the sediments. Using the unsteady-state model, which includes year-round processes, degradation was estimated to account for losses of 7-32% for the more persistent OCs and 42-50% for the less persistent OCs (alpha-HCH, gamma-HCH, and endosulfan I). If loadings were eliminated, water column concentrations would decline with half-lives <1 year for less persistent OCs and 1-2 years for the more persistent OCs, whereas the half-lives for OCs in sediment are 8-25 years. 相似文献
983.
984.
Seyed Mohammad Sajadi Cristiano F. Woellner Prathyush Ramesh Shannon L. Eichmann Qiushi Sun Peter J. Boul Carl J. Thaemlitz Muhammad M. Rahman Ray H. Baughman Douglas S. Galvo Chandra Sekhar Tiwary Pulickel M. Ajayan 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(52)
Lightweight materials with high ballistic impact resistance and load‐bearing capabilities are regarded as a holy grail in materials design. Nature builds these complementary properties into materials using soft organic materials with optimized, complex geometries. Here, the compressive deformation and ballistic impact properties of three different 3D printed polymer structures, named tubulanes, are reported, which are the architectural analogues of cross‐linked carbon nanotubes. The results show that macroscopic tubulanes are remarkable high load‐bearing, hypervelocity impact‐resistant lightweight structures. They exhibit a lamellar deformation mechanism, arising from the tubulane ordered pore structure, manifested across multiple length scales from nano to macro dimensions. This approach of using complex geometries inspired by atomic and nanoscale models to generate macroscale printed structures allows innovative morphological engineering of materials with tunable mechanical responses. 相似文献
985.
Margi Jani Dhyey Raval Ranjan Kumar Pati Indrajit Mukhopadhyay Abhijit Ray 《Bulletin of Materials Science》2018,41(1):22
Spray-pyrolysed zinc oxy-sulphide Zn(O,S) has been doped with varying concentrations of indium (In) to improve its electrical and optical properties for possible application as buffer layer in thin film solar cells. The In-doping in Zn(O,S) is found to change the electron carrier concentration from \(10^{19}\) to \(10^{18}\,\hbox {cm}^{-3}\) and a subsequent annealing in argon atmosphere is found to improve its electrical conductivity. Moreover, annealing in air atmosphere reduces the carrier concentration to a range of \(10^{13}\)–\(10^{15}\,\hbox {cm}^{-3}\) making it useful as a buffer layer. The reduction in degeneracy of In-doped Zn(O,S) is desirable for its application as buffer material, whereas annealing in argon makes it suitable as electron membrane (window layer) in thin film solar cell. 相似文献
986.
Shaheen Sultana Sushma Talegaonkar Bhaskar Ray Harvinder Singh F. J. Ahmad Gaurav Mittal 《Drug development and industrial pharmacy》2018,44(7):1171-1184
Introduction: In this study, different nifedipine-loaded formulations were prepared to treat pylorospasm, a sphincter muscle disorder characterized by delayed gastric emptying process. The efficacy of formulation was evaluated in patients by subjective assessment, gamma scintigraphic approaches, and confocal microscopy.Methods: Nifedipine-loaded different formulations such as sucrose bead, pellets, and microparticles (slugging method, ionotropic gelation, and chemical denaturation) were designed. The studies were performed on 50 subjects, of which 30 subjects were treated with optimized nifedipine loaded microcapsules while 20 subjects were given capsule becosule-Z as a control. The efficacy of formulation was assessed by comparing symptoms like dyspepsia, abdominal pain, abdominal fullness, poor appetite, nausea, vomiting, and irregular motion. The effectiveness of formulation was also assessed by gamma scintigraphic studies by determining the rate of emptying of a radioactivity labeled standard meal from patients’ stomach into the duodenum. Confocal microscopy was used to assess targeting potential of developed formulation.Results: Drug-loaded alginate-chitosan microcapsules were found to be satisfactory, in terms of controlled drug release, surface morphology, and bioadhesive properties and thus selected for in vivo studies. Clinical studies revealed the efficacy of formulation in abolishing various GI symptoms at high altitude. Associated symptoms such as dyspepsia, abdominal pain, poor appetite, nausea, vomiting, and irregular motion were recovered by 75, 62, 76.5, 86.7, 85.7, and 37.5%, respectively in nifedipine-treated patients. In comparison, 73.7, 40, 33.3, 40, 20, and 0% recoveries were observed in patients given control treatment only. Gamma Scintigraphic studies in lab also revealed 2.425?±?0.245 (p?.05) times improvement in gastric emptying rate in patients with diabetic gastroparesis. Confocal analysis showed better targeting and penetration in pyloric region when formulation was administered in form of high-density microcapsules.Conclusions: Results strongly suggest that nifedipine loaded mucoadhesive formulation has a targeting potential which accelerates gastric emptying process in gastroparesis patients, and thus the formulation might prove useful as a potent prokinetic agent. 相似文献
987.
Atri Nath Sudhirkumar V. Barai Kalyan Kumar Ray 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(12):2808-2822
Investigation on asymmetric cyclic‐plastic or ratcheting behaviour of non‐ferrous materials has received relatively little attention compared with ferrous materials. Ratcheting behaviour of materials is generally simulated using isotropic‐kinematic hardening models; however, for materials showing cyclically stable response, isotropic hardening is often not accounted for the constitutive modelling. A methodology based on Chaboche's isotropic‐kinematic hardening (CIKH) model with the consideration of genetic algorithm for optimization of initial estimates of the CIKH parameters is used in this study. The investigated plastic responses incorporate both symmetric strain‐controlled hysteresis loops and ratcheting behaviour. The suggested approach satisfactorily predicts the reported plastic response of cyclically stable non‐ferrous alloys based on aluminum, zirconium, and titanium. 相似文献
988.
Geri Georg Indrakshi Ray Kyriakos Anastasakis Behzad Bordbar Manachai Toahchoodee Siv Hilde Houmb 《Information and Software Technology》2009,51(5):846-864
We propose a methodology, based on aspect-oriented modeling (AOM), for incorporating security mechanisms in an application. The functionality of the application is described using the primary model and the attacks are specified using aspects. The attack aspect is composed with the primary model to obtain the misuse model. The misuse model describes how much the application can be compromised. If the results are unacceptable, then some security mechanism must be incorporated into the application. The security mechanism, modeled as security aspect, is composed with the primary model to obtain the security-treated model. The security-treated model is analyzed to give assurance that it is resilient to the attack. 相似文献
989.
In Trusted Network Connect (TNC), a network access decision is based on the security state of an access requesting party. This mechanism is limited to closed environments such as LANs and VPNs. In this paper, we propose solutions based on authentication standards for enabling TNC in open, web-based scenarios. In particular, an architectural model for TNC is proposed that takes additional security and privacy requirements into account. Furthermore, a communication scheme is proposed that is based on standardised protocols and message formats. This approach provides assurance as to the security state of clients accessing security sensitive web-based services. 相似文献
990.
With a plethora of models, systems and standards to choose for a basis of software process improvement, decisions on which
to adopt may depend on a number of factors. This paper presents an evolutionary and extremely cost effective approach to implementing
a software quality system that requires minimum resource and little disruption to programme delivery. The method presented,
achieved a 40% improvement in the level of implementation of the AWE plc software quality management system over a 5-year
period. A critical success factor is the treatment of the users’ of the defined software quality system as customers, understanding
their concerns and problems, and being responsive to them. The importance of a well designed system is highlighted together
with the essential and extensive consultation process required to gain buy-in and lay the foundation for cultural change.
This was supported with a helpful programme of facilitated self-assessment and sustained by a closely aligned training scheme.
As a consequence some of the cultural elements were changed from one of thoughtless “tick-in-the-box” compliance to one of
true understanding of the system requirements, true quality implementation, and subsequent added value.
Michael Elliott is a Chartered Engineer and member of the British Computer Society. He is the Sodftware Quality Manager at the Atomic Weapons Establishment (AWE) in the UK and is accountable to ensure the certification to ISO 9001:2000 for all software related activities. Mike’s particular interest is the intricacies of dealing with different people in a culturally diverse establishment, such as AWE. He has recently completed post graduate research at Loughborough University with Ray Dawson and Janet Edwards. His thesis was entitled “Achieving business excellence in software quality management”. The research investigated the practical nuances of the internal auditing, the adoption of self-assessment as a methodology, the cost effectiveness of training and the cost-benefits associated with implementing best practice in software quality management. Ray Dawson obtained a Bachelor’s degree in mathematics with engineering and a masters degree in engineering from Nottingham University before entering industry with Plessey Telecommunications in 1977. While working at the company he developed an interest in the working methods for software development as practiced in industry. This became a research interest when he joined Loughborough University as a lecturer in 1987. Other research interests are information systems and knowledge management which he now combines with his interest in industrial working practices to work with companies to improve their information and knowledge management systems. Ray Dawson is now a Senior Lecturer in the Department of Computer Science and leader of the Knowledge Management Research Group at Loughborough University in the UK, and is a Chartered Engineer and fellow of the British Computer Society. Janet Edwards has recently retired as a lecturer in Computer Science at Loughborough University. She has a Btech (Hons) degree in Metallurgical Engineering and Management and an MSc degree by research in Robotic Control from Loughborough University. She spent a number of years working as a software engineer in various organisations before returning to Loughborough. Her current research interests include Electronic Communication and E-commerce. 相似文献
Janet EdwardsEmail: |
Michael Elliott is a Chartered Engineer and member of the British Computer Society. He is the Sodftware Quality Manager at the Atomic Weapons Establishment (AWE) in the UK and is accountable to ensure the certification to ISO 9001:2000 for all software related activities. Mike’s particular interest is the intricacies of dealing with different people in a culturally diverse establishment, such as AWE. He has recently completed post graduate research at Loughborough University with Ray Dawson and Janet Edwards. His thesis was entitled “Achieving business excellence in software quality management”. The research investigated the practical nuances of the internal auditing, the adoption of self-assessment as a methodology, the cost effectiveness of training and the cost-benefits associated with implementing best practice in software quality management. Ray Dawson obtained a Bachelor’s degree in mathematics with engineering and a masters degree in engineering from Nottingham University before entering industry with Plessey Telecommunications in 1977. While working at the company he developed an interest in the working methods for software development as practiced in industry. This became a research interest when he joined Loughborough University as a lecturer in 1987. Other research interests are information systems and knowledge management which he now combines with his interest in industrial working practices to work with companies to improve their information and knowledge management systems. Ray Dawson is now a Senior Lecturer in the Department of Computer Science and leader of the Knowledge Management Research Group at Loughborough University in the UK, and is a Chartered Engineer and fellow of the British Computer Society. Janet Edwards has recently retired as a lecturer in Computer Science at Loughborough University. She has a Btech (Hons) degree in Metallurgical Engineering and Management and an MSc degree by research in Robotic Control from Loughborough University. She spent a number of years working as a software engineer in various organisations before returning to Loughborough. Her current research interests include Electronic Communication and E-commerce. 相似文献