Multiple quasi-phase-matched device using continuous phase modulation of /spl chi//sup (2)/ grating and its application to variable wavelength conversion

We propose a new multiple quasi-phase-matched wavelength converter based on the continuous phase modulation of a /spl chi//sup (2)/ grating for use in variable wavelength conversion. A numerical study shows that the proposed device exhibits a high conversion efficiency, flexible design, and robust fabrication tolerance. A waveguide device fabricated by annealed proton exchange agrees well with the numerical design. Fine-tuning the device enabled us to demonstrate variable wavelength conversion between signals on the standard optical frequency grid. Using the device, we also demonstrated fast (<100 ps) wavelength switching of 4-channel 40-Gb/s signals. The obtained results clearly show that the proposed multiple quasi-phase-matched devices will be useful when constructing future flexible photonic networks.     

Dual Gabor frames: theory and computational aspects

We consider a general method for constructing dual Gabor elements different from the canonical dual. Our approach is based on combining two Gabor frames such that the generated frame-type operator S/sub g,/spl gamma// is nonsingular. We provide necessary and sufficient conditions on the Gabor window functions g and /spl gamma/ such that S/sub g,/spl gamma// is nonsingular for rational oversampling, considering both the continuous-time and the discrete-time settings. In contrast to the frame operator, the operator S/sub g,/spl gamma// is, in general, not positive. Therefore, all results in Gabor analysis that are based on the positivity of the frame operator cannot be applied directly. The advantage of the proposed characterization is that the algebraic system for computing the Gabor dual elements preserves the high structure of usual Gabor frames, leading to computationally efficient algorithms. In particular, we consider examples in which both the condition number and the computational complexity in computing the proposed dual Gabor elements decrease in comparison to the canonical dual Gabor elements.     

Acidogenic fermentation of blended food‐waste in combination with primary sludge for the production of volatile fatty acids

The performance of a laboratory‐scale anaerobic acidogenic fermenter fed with a mixture of blended kitchen food‐waste and primary sludge from a sewage treatment plant was investigated for the production of volatile fatty acids (VFA). The operating variables for acidogenic fermentation were kitchen food‐waste content (10 and 25 wt %), hydraulic retention time (HRT: 1, 3 and 5 days), temperature (ambient: 18 ± 2 °C, and mesophilic: 35 ± 2 °C) and pH (varied from 5.2 to 6.7). The experimental results indicated that effluent VFA concentrations and VFA production rates were higher at ambient temperature than at mesophilic conditions. The net amount of VFA with 10 wt % food‐waste increased up to 920 mg dm^?3 with an increase of HRT, but contrasting results (a decrease of 2610 mg dm^?3) were found due to the conversion of VFA into biogas in the case of 25 wt % food‐waste, which increased significantly at HRT of 3–5 days. In terms of biogas composition (CO₂ and CH₄), the organic matter was converted into CO₂ through the oxidative pathway by facultative species at low temperature while mesophilic temperature and optimum pH (6.3–7.8) played a pivotal role in increasing rate of conversion of VFA into biogas by methanogenesis. Rates of VFA production and their conversion are dependent on the food‐waste content in the mixture. Yet, the higher concentration of food‐waste (25% compared with 10%) did not produce VFA proportionally due to the increased rate of conversion of VFA into gaseous products. The maximum VFA production rate (0.318 g VFA_produced g^?1 VS_fed day^?1) was achieved in the 10 wt % food‐waste at ambient temperature and at a 5‐day HRT. Copyright © 2005 Society of Chemical Industry     

Intraoperative neurological monitoring

Intraoperative neurological monitoring (INM) is the evaluation of the nervous system within the operating room (OR) environment. In this paper, the INM system is tested in a clinical setting in comparison with conventional somatosensory evoked potential (SEP) monitoring. The study results demonstrate the capability of the INM system in extracting clearer and more stable SEP signals. The high SNR of SEP signals collected in various clinical environments, including the OR, makes the INM system a robust platform for continuous monitoring. While the current use of EP monitoring is limited to intermittent analysis by a highly trained clinical neurophysiologist, the authors believe in changing this paradigm by developing continuous monitoring systems, such as the INM system, capable of automated quantitative EP analysis. This noninvasive monitoring modality will allow for a wider range of use in clinical practice. Based on volunteer and clinical patient studies, the INM monitoring system demonstrates much greater reliability and accuracy via the artifact rejection and denoising strategies. It provides more strategic filtering options for different situations under which the clinical SEP response signal could be greatly contaminated and distorted. Furthermore, the INM system offers a promising approach to signal extraction in real-time monitoring during SEP research.     

来宾电厂改扩建工程电气主接线方案研究

根据来宾电厂改扩建工程的实际情况，从技术、经济上介绍工程电气主接线及高压出线的各个不同方案的优缺点，通过分析比选，得出最优推荐方案。     

知识驱动的UG中的产品开发

重点论述了UG中的KBE即KF模块的知识驱动产品开发设计过程及其关键技术，介绍了知识驱动自动化过程，实例剖析了UG中的KF在产品开发设计过程中的应用。     

连续式超临界流体萃取进卸料装置

概括了超临界流体萃取技术和包括连续式操作在内的超临界流体萃取装置的研究现状 ,提出了一种通过球形进、卸料器完成固相物料超临界流体萃取连续化进卸料的装置 ,介绍了该装置的结构和工作原理 ,给出装置中各主要部件的计算方法。     

重庆双龙湖富营养化限制性因素确定试验研究

双龙湖是浅水型城市湖泊,一度为重富营养化湖泊。综合治理后水体仍处于中-富营养化。探求富营养化限制性因素对于防治双龙湖富营养化、维护双龙湖水质至关重要。本文通过双龙湖藻类增长潜力试验研究,确定双龙湖富营养化限制性因素是磷,这对于采取适宜管理措施修复水体、保持水质具有重要意义,为湖泊治理、水环境保持提供科学依据。     

“业主想要的，又是业主没想到的”

大约1年前，接到陈怡姝在深圳某会的讲稿，题目是“互动设计”其内容简言之：在设计全过程中，业主的要求和建筑师的专业技能不断磨合，使建筑设计不断升华，达到一定水准。互动设计可能就是他们不断赢得业主，占有一定市场的原因。而今又读了她的“适度技术、本质设计”的文章。我的体会是，“适度技术，本质设计”是互动设计理念在飞亚达高科技大厦工程中的具体化，正如文中所说，适度设计与本质设计与投资方达成共识，在造价经济、功能合理的基础上表达理性，务实的理念。     

应用型机械本科专业教学体系改革研究与实践

根据当前高等教育改革与发展的指导思想，紧紧围绕国家实施制造业信息化建设工程为背景，积极配合打造浙江先进制造业基地建设，结合现代机械专业结构调整，本着交叉、复合、应用型人才的培养目标，塑造具有宽口径、厚基础和强创新意识的人才培养理念，以数字化设计制造为核心，以机械技术、电子技术、信息技术和管理学科结合为主线，突出知识综合与创新能力，强调专业实践与专业知识的有效结合，有的放矢实施机械专业教学改革与实践。