无线电频谱监测与分析系统设计及实现

针对目前频谱监测系统的不足之处,给出了能够满足各地无线电管理部门需要的便携式、职能化、监测频谱范围宽的频谱监测系统的设计与实现方法.系统利用了动态库、VC操作Word以及并行处理的技术,重点针对低噪声放大器、驱动电机、天线控制器和干扰电平的计算进行了设计,系统能够完成频谱数据的采集、天线转动角度的采集、监测点地理信息的采集以及对采集的数据进行分析处理,最后自动生成监测报告.     

基于数字建构的AR现实交互听障辅助系统设计研究

目的 以提升听障患者生活质量为目标,尝试在增强现实交互技术的帮助下以视觉上的扩展来弥补听障缺陷,并将数字建构产品作为最终物态进行呈现。方法 以数字建构的设计方法与增强现实的技术路径为指导,针对听障患者的具体需求展开探讨,研究了数字建构下增强现实交互听障系统深度开发的可能性,为后续设计提供了思路并最终得出方案。结论 随着计算机硬件计算速度的提升,计算机处理多任务的能力更为出色,增强现实交互技术得以通过连接设备,将虚拟世界投射到现实世界中。利用此特性,以数字建构的方式集成智能设备,有助于弥补人体的多种生理缺陷,为残障人士建立与外界正常沟通的介质,具有重要的理论与实践意义。     

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在总结国内外水下穿越管道事故原因的基础上，从地质勘察、工程设计、施工质量、后期维护管理和河流环境等五个方面详细讨论了影响水下穿越管道埋深的主要因素。据此提出一种确定水下穿越管道设计埋深的新方法，即在常规设计的基础上，对影响水下穿越管道埋深的各种模糊因素进行综合评价；采用多级模糊综合评判法确定设计埋深的加深系数，将加深后的管道埋深作为穿越管道的设计埋深，并通过实例验算表明该方法符合工程实际。     

Nucleophilic substitution onto poly(methylmethacrylate): 4. Dilute solution properties of substituted polymethacrylates

The morphological and hydrodynamic properties of a series of homogeneous fractions of substituted poly(methylmethacrylate) (A units) bearing keto-β-functional groups (B units) of the general structureCOCH₂R, with R = SO_xCH₃ (x = 1,2) or SO₂N(CH₃)₂, were investigated by intrinsic viscosity, light scattering and partial specific volume measurements in dimethylformamide (DMF) solution at 25°C. For molar substitution degrees $\text{DS}{}_{\mathrm{m}}\text{< 0.5}$, the copolymers behave as flexible random coils. The Stockmayer-Fixman-Yamakawa analysis of the $\text{[η]-}\text{M}\text{?}{}_{\mathrm{w}}$ data leads to slightly higher unperturbed dimensions K_o and steric factor σ than those for PMMA, and to stronger chain expansion as a result of the weak hydrogen bonding between DMF and COCH₂R units and a positive X_AB interaction parameter. For $\text{DS}{}_{\mathrm{m}}\text{> 0.5}$ however, copolymers bearing COCH₂SO₂N(CH₃)₂ groups behave as worm-like chains, as derived from the Fujii-Yamakawa analysis of the $\text{[η]-}\text{M}\text{?}{}_{\mathrm{w}}\text{-}\text{v}\text{?}$ data: the persistence length increases from 380 to 570 Å within the $\text{DS}$_m range 0.57–0.75. This transition from a random coil to a worm-like chain for $\text{DS}{}_{\mathrm{m}}\text{> 0.5}$ was tentatively correlated with the accumulation of B units in sterically hindered and self-associated short blocks of average length l_B ? 1.6 which provide drastically increased rigidity to the copolymer chain.     

Characterization of edible oils and lard by fourier transform infrared spectroscopy. Relationships between composition and frequency of concrete bands in the fingerprint region

Fourteen samples of edible oils and lard have been studied by means of Fourier transform infrared spectroscopy. The spectra were recorded from a film of pure oil or lard between two discs of KBr. The bands of the spectra were assigned to different functional group vibrations. The frequencies of some bands have constant values, independent of the nature of the sample. However, frequencies of other bands, some of them in the fingerprint region, depend greatly on the sample composition. Equations obtained from frequency of these bands and composition data are valuable to predict the proportions of saturated, monounsaturated and polyunsaturated acyl groups in oils and lard.     

Control of hydroxyl group content in silica particle synthesized by the sol-precipitation process

This study investigated the control of hydroxyl groups, one of key factors determining the surface properties of silica particles synthesized by the sol-precipitation of tetraethyl orthosilicate (TEOS). Thus, a thermal gravity analysis (TGA) was used to facilitate quantitative measurements of the hydroxyl groups on the silica particles, while BET and FT-IR were used to analyze the specific surface area and functional silane groups on the silica particles, respectively. In the sol-precipitation process, silanes that include various hydroxyl groups are formed as intermediates based on the hydrolysis and condensation of TEOS. Thus, NH₃, as a basic catalyst initiating the nucleophilic substitution of TEOS, was found to accelerate the hydrolysis and increase the hydroxyl group content on the silica particles. Plus, the hydroxyl group content was also increased when increasing the concentrations of TEOS and water as the hydrolysis reactants. However, the hydroxyl group content was reduced when increasing the temperature, due to the promotion of condensation. Based on the weight loss of the particles according to the thermal analysis, the hydroxyl group content on the silica particles varied from 5.6–42.7 OH/nm² under the above reaction conditions.     

Surface chemistry of phosphorus-containing carbons of lignocellulosic origin

Activated carbon adsorbents were prepared by phosphoric acid activation of fruit stones in an argon atmosphere at various temperatures in the 400-1000 °C range and at different acid/precursor impregnation ratios (0.63-1.02). The surface chemistry of the carbons was investigated by elemental analysis, cation exchange capacity (CEC, measured by neutralization of NaOH with acidic surface groups), infrared spectroscopy and potentiometric titration. Porous structure was derived from adsorption isotherms (N₂ at −196 °C and CO₂ at 0 °C). It was demonstrated that all carbons show considerable cation exchange capacity, the maximum (CEC = 2.2 mmol g⁻¹) being attained at 800 °C, which coincides with the maximum contents of phosphorus and oxygen. The cation exchange properties of phosphoric acid activated carbons from fruit stones are chemically stable in very acidic and basic solutions. Proton affinity distributions of all carbons show the presence of three types of surface groups with pK at 2.0-3.3, 4.6-5.9 and 7.6-9.1. These pK ranges were ascribed primarily to: (a) phosphorus-containing and carboxylic groups; (b) lactonic groups, and (c) phenolic groups, respectively. Phosphoric acid activated carbons are microporous with a relatively small contribution of mesopores. A maximum BET surface area of 1740 m² g⁻¹ was attained at 400 °C.     

创新要素集聚与区域创新绩效研究——基于浙江中小企业的实证分析

本文在对浙江中小企业发展模式探讨的基础上,以人才要素、资金要素、技术要素和研发要素四个维度构建了浙江中小企业创新要素集聚的评价指标体系,并且对中小企业创新要素集聚与创新绩效之间的关系进行了理论论述和实证分析。研究结果发现,人才要素、技术要素是推动浙江中小企业创新绩效提升的关键因素,而中小企业集群所衍生出的内部“技术锁定”是影响中小企业资金要素、研发要素对创新绩效产生作用的原因所在。     

咖啡纤维结构与性能研究

介绍了咖啡纤维的生产过程和物理性能,通过红外光谱仪、X射线粉末衍射仪和扫描电子显微镜研究了咖啡纤维的亲水基团、吸湿性、结晶度和形态结构等,并与棉纤维和麻纤维进行了对比,证明了咖啡纤维的可纺性,有利于咖啡纤维的进一步开发和利用.     

基于GIS的焦作市城区大气SO2污染源解析

为实现焦作市城区大气污染预测,作者通过分析城区大气SO2污染的年际变化特征和地域分布特征,利用GIS技术对城区的大气SO2污染进行了空间分析;研究了焦作市城区大气SO2污染与污染源分布的内在关系,并建立了SO2污染解析模型．研究结果表明,焦作市城区大气SO2污染与工业污染源的布局是一致的,说明工业燃煤是焦作市大气SO2污染的主要原因．