中外CBD研究分析与比较

从文献统计和综述的角度入手,通过样本数据特征和关注度图谱分析相结合的方法,对CBD的研究阶段进行了划分,对国内外关于CBD研究的特征、内涵、演变规律进行了研究.认为国外CBD研究的演变过程和动力机制与国内存在着较大差异,研究内容出现了同构性和异质性并存的特征,故须理性对待我国CBD的研究与实践探索.     

竖向集约与CBD规划反思

国内CBD存在片面追求形态美而导致CBD空间集聚效益下降的问题。在商务集聚、集中发展原因剖析的基础上,指出市场经济下"CBD择址的高通勤可达性区位指向"和"CBD的高强度发展特性"。结合CBD适宜的公共交通模式,阐述了CBD的竖向集约发展需求。高密度、高强度的建筑布局模式是CBD健康发展的内在需求,也是将公共交通出行的一端牢牢的确定在CBD较小且适宜的步行范围内,是促进城市集约发展的关键。     

Ionic liquid based periodic mesoporous organosilica: An efficient support for removal of sunset yellow from aqueous solutions under ultrasonic conditions

The efficiency of an ionic liquid based periodic mesoporous organosilica (PMO-IL) in the removal of sunset yellow from aqueous solutions using ultrasonic assisted adsorption method was investigated. The PMO-IL was first characterized by nitrogen sorption and TEM techniques. The optimized conditions (0.013 g of adsorbent, 32 mg L⁻¹ of sunset yellow at 2 min of sonication time and pH 7) were obtained by central composite design (CCD). Fitting the equilibrium data show the suitability of the Langmuir model with second-order equation to control the kinetic of the adsorption process and good reusability (5 cycles) of PMO-IL for adsorption of dye.     

分散锅炉房集中监测系统的开发与应用

为提高供热质量和设备运行管理水平,研制了分散锅炉房集中监测系统,研制成功被天津确认为天津市科研成果。     

Ecological consequences of hydropower development in Central America: impacts of small dams and water diversion on neotropical stream fish assemblages

Small dams for hydropower have caused widespread alteration of Central American rivers, yet much of recent development has gone undocumented by scientists and conservationists. We examined the ecological effects of a small hydropower plant (Doña Julia Hydroelectric Center) on two low‐order streams (the Puerto Viejo River and Quebradon stream) draining a mountainous area of Costa Rica. Operation of the Doña Julia plant has dewatered these streams, reducing discharge to ～10% of average annual flow. This study compared fish assemblage composition and aquatic habitat upstream and downstream of diversion dams on two streams and along a ～4 km dewatered reach of the Puerto Viejo River in an attempt to evaluate current instream flow recommendations for regulated Costa Rican streams. Our results indicated that fish assemblages directly upstream and downstream of the dam on the third order Puerto Viejo River were dissimilar, suggesting that the small dam (< 15 m high) hindered movement of fishes. Along the ～4 km dewatered reach of the Puerto Viejo River, species count increased with downstream distance from the dam. However, estimated species richness and overall fish abundance were not significantly correlated with downstream distance from the dam. Our results suggested that effects of stream dewatering may be most pronounced for a subset of species with more complex reproductive requirements, classified as equilibrium‐type species based on their life‐history. In the absence of changes to current operations, we expect that fish assemblages in the Puerto Viejo River will be increasingly dominated by opportunistic‐type, colonizing fish species. Operations of many other small hydropower plants in Costa Rica and other parts of Central America mirror those of Doña Julia; the methods and results of this study may be applicable to some of those projects. Copyright © 2006 John Wiley & Sons, Ltd.     

松辽盆地晚中生代裂谷作用与伸展构造样式

松辽盆地中西部的裂谷作用自下白垩统沙河子组沉积期持续到营城组沉积期,东部从下白垩统沙河子组沉积期持续到登娄库组沉积期.在不同构造层次形成了变形特征有别的构造,中浅层伸展构造的基本要素是断陷盆地边界主断裂,基本结构单元是半地堑和半地垒,横向上呈多米诺型垒-堑构造.主断裂中东倾者倾角缓但向东有增大的趋势;西倾者数量有限但倾角较陡.断陷包括水平拉张量大而裂谷期沉降量小的半地堑和水平拉张量小但裂谷期最大沉降的半地堑.这些断陷盆地在北北东方向呈串珠状,自西而东成带.在中-下地壳发生韧性变形,形成一向东倾拆离带,深度范围15～30km. 裂谷的扩展有3种方式,即边界断裂的斜向后退扩展,断陷带的走向式扩展,断陷群的横向扩展.     

实心橡胶自行车胎动力学特性及影响因素分析

轮胎是自行车的重要组成部分和承载部件.本研究基于某品牌单车实心橡胶轮胎,通过橡胶超弹-黏弹本构模型的建立,对实心橡胶轮胎进行瞬态动力学仿真,分析其应力、应变,中心轴垂直位移等特性,得出材料与轮胎应力、应变、中心轴在垂直方向跳动之间的关系.结果表明:橡胶材料硬度对应力、应变以及轮胎中心轴垂直方向跳动均有较大影响;利用正交...     

HRV系列降粘剂在冀中南部稠油开采中的应用

为解决冀中南部１０多个稠油油藏原油粘度高,开采难度大的问题,开发了应用ＨＲＶ系列乳化降粘剂开采此类油藏的新方法,解决了稠油在地层,井筒难以流动的问题,而且使稠油的地面输送简单化现场应用表明,ＨＲＶ系列稠油乳化降粘剂使用浓度小,乳化效率高,降粘效果好,同时不影响原油破乳,具有较大的推广使用价值。     

四川盆地中部中二叠统热液白云岩储渗空间类型及成因

近年来,四川盆地川西北地区有多口井在中二叠统栖霞组、茅口组钻获高产气流,展现出该层系巨大的天然气勘探潜力,但有关该盆地中二叠统白云岩储层的成因机理则众说纷纭,一直未达成共识。为此,基于川中地区栖霞组、茅口组岩心及薄片等岩相学特征,以及碳、氧、锶同位素和包裹体均一化温度等地球化学特征,开展了中二叠统热液白云岩储渗空间类型及储渗相特征研究,分析了白云岩储层的成因及其控制因素。结果认为:(1)茅口组、栖霞组石灰岩地层经历了构造控制热液活动,发育萤石、鞍状白云石、天青石的热液矿物组合和膨胀角砾结构;(2)较之于宿主石灰岩,细—中晶云岩和鞍状白云石均呈现出δ18O负偏移、87Sr/86Sr正偏移;(3)中二叠统形成由热液溶孔、热液白云岩晶间孔、热液溶洞、热液扩溶缝等4种储渗空间构成的热液白云岩储渗体。结论认为:(1)热液白云岩储集相发育和分布受深大断裂的控制,呈"透镜状"分布在具"下凹"地震反射特征的区域;(2)中二叠统热液白云岩储集相与下伏烃源岩和上覆封堵层的有机组合可构成有利的天然气勘探目标。     

海—塔盆地中部断陷带南二段油藏主控因素及模式

通过油藏解剖和油藏与成藏条件之间空间匹配关系研究,认为:海—塔盆地中部断陷带南二段油藏主要为分布在断阶带、断鼻和洼中隆上的断层油藏;南二段油藏分布受南一段源岩分布范围、断陷中断阶带和洼中隆的位置、扇三角洲前缘亚相砂体分布、早期伸展断裂沟通生油岩与储层程度等4个主要因素控制;油气成藏模式为洼槽中南一段源岩生成的油气在浮力作用下,通过早期伸展断裂错断与南二段储层侧接,向断阶带或洼中隆上的断块和断层—岩性圈闭中运移聚集成藏的模式.