On-line determination of supersaturation of a kcl-nacl aqueous solution based on density measurement

A method is developed for the calculation of the saturation temperature of a KCI-NaCI aqueous solution, based on the measurement of the density and temperature of a sample solution, and prior knowledge of the NaCl concentration. Experimental density and solubility data for solutions saturated with KCI in the temperature range of 299 to 321 K with concentrations of NaCl greater than 0.200 kg/kg H₂O were used to develop the empirical correlation allowing the calculation of the solution saturation level. The method is applicable in the on-line determination of the level of supersaturation in a KCI crystallizer in which the NaCl concentration is known. Knowledge of the prevailing supersaturation is necessary for the control of crystal purity and crystal size distribution in industrial potash crystallizers.     

A new maritime lifesaving multiple-effect solar still design

This paper presents a new maritime lifesaving multiple-effect solar still design where several extended wicks feed seawater to their evaporating areas by capillary force, and the resulting water vapor diffuses and condenses on facing wicks with the condensate flowing through the wicks into storage bags. A theoretical analysis showed that a temperature drop through diffusion layers between evaporating and condensing wicks slowly increases in the main evaporating areas and rapidly near salt depositions whereas the evaporation rate decreases slowly in the main area and rapidly near salt depositions. These changes are caused by increases in salt concentrations and resulting boiling point elevation. With steady-state transfer analysis, the proposed still is predicted to produce about 15 kg m ⁻²d⁻¹ fresh water on a sunny day of 22 MJm⁻²d⁻¹ solar radiation, showing a potential to be a maritime lifesaving desalinator.     

网站数据相关内容提取功能的设计与研究

本文根据内容提取的相关知识,以及它们在用户浏览信息时的应用,提出了内容匹配的高效算法,重点研究提取信息时如何提高匹配精度。通过这种算法,系统预测用户可能感兴趣的文章,并按感兴趣的程度向用户提供内容导航,得到一个个性化的相关信息显示页面。     

The use of a mixing-sensitive chemical reaction for the study of pulp fibre suspension mixing

The competitive, consecutive chemical reactions between 1-naphthol and diazotized sulfanilic acid were utilized to study the mixing of a pulp fibre suspension in a 22 L stirred tank reactor. Mixing quality was determined from the distribution between the mono and bis substituted reaction products once a correlation was made for the adsorption of the product dyes onto the suspended fibres. The technique was found to be adequate for assessing micromixing and turbulence intensity within a fibre suspension provided the measured product distribution, Xs, was between 0.4 and 0.01. Thus the mixing conditions that could be assessed depended on both the energy dissipation within the mixer and the amount of the fibre present. For the experimental conditions chosen for this study energy dissipation rates would typically have to be less than 80 W/kg and the suspension mass concentration less than 2.5%. When compared with water, a reduction in turbulence levels at both the impeller zone and a remote zone in the stirred vessel was observed for fibre mass concentrations as low as 0.5%. The turbulence decreased as the suspension mass concentration was increased. This decrease is attributed to energy dissipation by friction at fibre-fibre contact points as the fibres move relative to one another in the flow. This sink removes energy from the turbulence cascade which never shows up as small-scale fluid deformations leading to better mixing.     

湖北省健康中心村可持续发展研究

摘 要 中心村在发挥最初的人口、耕地、资金集聚效应后,出现农业产业化、规模化亟需升级与环境污 染严重、辐射能力受限、就业吸纳效应下降、经济发展后劲不足诸多问题,通过健康村发展循环经济的实 践,划分健康村功能布局、分区探索中心村可持续的发展方向和增长方式。     

政府参与循环农业发展的行为与作用机理分析  ———基于湖北省的实证调研

摘 要 该文从经济学角度对政府参与循环农业发展的作用机理进行了探讨,并结合对湖北省两个国家级 和4个省级生态农业试点县（市）的实地调研,对政府参与循环农业发展的实践行为进行了分析。研究结 论表明:“市场失灵”和循环农业的经济特性是政府参与循环农业的根源所在。当前中央和地方各级政府 围绕循环农业的发展,分别从规划、立法和政策引导、项目推进、环境监管等方面着力推进循环农业的发 展,并取得了较好的实效。与此同时,政府在循环农业发展中仍然存在一些缺陷和不足之处,如政策和法 制体系仍然有待完善、公共基础设施投入不足,技术支撑体系尚未建立等。鉴于此,提出政府应进一步完 善法律法规和政策体系,加强循环农业公共物品的供给、建立地方党政领导主抓循环农业发展责任制等几 个方面。     

河南省花卉产业发展现状及对策分析

摘 要 河南省是我国重要的粮食主产省,也是我国重要的花卉传统生产区域之一。在保障粮食生产目标 顺利实现的同时,利用特色资源发展特色农业,是促进农民增收的有效途径。该文在分析河南省花卉产业 发展的基础、存在的问题、面临的发展机遇后,提出了河南省花卉产业发展的若干对策:升级花卉产业结 构,发展特色花卉细分品种系列;优化花卉产业布局,发挥产业集聚效应;延伸花卉产业链;发挥南北过 渡带的地缘优势;创新花卉产业组织模式等。     

我国土地资源配置的“双失”问题及对策研究

摘 要 研究目的:从西方经济学的原理出发,通过对我国土地资源配置中市场失灵和政府失灵问题的分 析,寻求在市场和政府的双重作用机制下土地资源高效配置的实现途径。研究方法:文献资料分析法、比 较分析法。研究结果:在市场经济条件下,单纯地依靠市场或政府,不可能实现我国土地资源的优化配置, 必须将二者结合起来,以规划的宏观调控来弥补和矫正市场失灵的缺陷,但是当前的土地利用规划存在失 效的负面影响。研究结论:应该从加强土地利用规划的政府宏观调控与完善土地市场机制两个途径入手, 实现土地资源的高效配置。     

我国4省农民思想教育现状分析及对策研究

摘 要 加强农民教育,提高农民素质,培养新型农民是建设社会主义新农村的现实需要,是当前农业与 农村工作中一项十分紧迫的任务。该文从社会学视角,结合陕西、河南、山东、江西4省样本,对当前农 民思想素质教育问题进行较为深入的探讨,在此基础上,提出了今后农民思想教育发展的思路。     

基于淘宝直通车的竞价决策系统的研究与设计

电子商务蓬勃发展的大环境下,广告主具有强烈的电商广告投放意愿,显然他们并未达到电商广告的核心业务SEM （搜索引擎营销优化）的专业要求。所以广告主希望借助第三方工具来进行搜索引擎广告投放的一站式服务来满足其业务需求。基于此,本文将提供一整套的竞价词托管式服务的解决方案。以淘宝直通车这一全新的搜索竞价模式作为研究对象,从语义抽取、关键词扩展、竞价词生成、模型化出价、广告效果正向反馈监控模型几方面进行分析和统计,为直通车广告主提供最优投放策略整体解决方案。第一阶段针对商品信息进行数据挖掘,实现关键词推荐引擎。第二阶段实现投放优化模块,实施定价策略,建立的点击量与PPC（“平均点击花费”）模型,实现在预算资金的约束下对不同竞价组合进行ROI（投入产出比）最大化的投资决策。以实际效果改善直通车竞价搜索用户体验。