低温无固相钻井液配方优选及经济性评价

为解决高原冻土和天然气水合物勘探过程中钻进和取心问题,选择了NaCl作为抗冻剂,抗盐共聚物GTQ和水解聚丙烯酰胺PHP作为主要聚合物试剂,采用正交试验法,在常温下优选出了9组配方,经过低温测试,确定了在 -15 ℃可用的钻井液配方Z1（20%NaCl+0.1%PHP+1.2%GTQ+1%KHm）和Z2（25%NaCl+0.15%PHP+1.0%GTQ+1%KHm）,其主要性能指标分别为：AV值46.5、47.5 mPa·s,PV值34、35 mPa·s,YP值12.8、12.8 Pa,FLAPI值6.8、7.6 mL/30 min。经成本核算,2种配方具有比较好的经济性,可以满足高原冻土层钻进要求。     

基于改进RANSAC算法的复杂建筑物屋顶点云分割

屋顶模型重建影响到建筑物完整模型重建质量,屋顶面点云分割质量对屋顶模型重建具有重要意义。针对传统RANSAC算法在屋顶点云面片分割时易产生错分割、过分割等问题,本文顾及点云位置信息,提出一种对点云重新分配的改进RANSAC点云分割算法。算法暂时剔除非平面内点,选取平面内点集中3个点作为初始样本,平面拟合判定邻域是否有效,从有效邻域中选取标准差值最小的3个点为初始模型。利用RANSAC算法对屋顶点云进行分割。利用K近邻算法统计误分类点与面片的距离降低误分类,优化过分割面片并进行连通性分析,利用距离及法向量一致性检验的方法重分配非平面内点。为验证本文算法有效性,选取芬兰Helsinki地区的3栋相互独立的复杂建筑物屋顶以及上海某小区的6栋建筑物群屋顶作为实验数据。在2组数据中,本文提出的改进RANSAC算法分割屋顶面片的平均准确率分别为92.17%、87.82%,78%的建筑物屋顶不存在过分割。在第2组数据中,所有分割面片上的点与其对应的最佳拟合平面的距离的标准差的平均值为0.030 m。实验结果表明,本文算法分割建筑物屋顶面片的准确率较高,较好的抑制了过分割现象,且抗噪能力强。     

基于模糊数学评价法优化凡纳滨对虾真空微波干燥工艺

【目的】探求真空微波干燥凡纳滨对虾的最佳工艺条件,以期为开发凡纳滨对虾即食食品提供技术参考。【方法】以新鲜凡纳滨对虾为原料,模糊数学感官评分为主要考察指标,在单因素试验基础上,选择载装量A、功率B、真空度C为自变量,利用响应面法和模糊数学评价法对真空微波干燥工艺进行优化。【结果】以感官评定为基础对真空微波干燥凡纳滨对虾的品质进行权重分析,得到权重集K=(色泽0.335,滋味0.305,香气0.215,组织质地0.145)。建立二次多项回归方程:Y=84.588+1.084A+1.409B+1.700C-7.353A²-8.793B²-13.860C²,显示载装量A、功率B、真空度C对感官评分有极显著影响(P<0.01)。通过响应面分析,得到真空微波干燥凡纳滨对虾的最佳工艺条件:载装量75 g,加热功率400 W,真空度0.08 MPa。在此条件下,真空微波干燥凡纳滨对虾品质良好,感官评分为(85.6±0.07)分,与预测值85.92分误差较小。【结论】响应面法优化凡纳滨对虾真空微波干燥工艺具有操作简单、优化条件精确、结果显示直观等优点;建立的回归方程能反映装载量等三个因素对指标的影响规律,并可进行实际预测。     

中国产业结构优化路径与碳排放趋势预测

中国已进入产业结构深度调整时期,同时产业升级也是减排的主要途径之一.为此,本文通过构建分部门跨期优化模型,以需求驱动和产业部门供给为基础,假设中国的消费偏好模式不断向发达国家(如美国、欧盟和日本)趋近,对消费偏好导向下的产业结构优化方向及碳排放趋势进行了模拟研究.结果显示,中国的农业和衣食制造部门比重将呈下降趋势,其他服务业部门比重会不断提高.在中国当前消费偏好模式下,重工业、交通运输、化工和金属等高耗能部门的比重仍将增加,而转向美国消费偏好模式后,这些部门的比重都将下降.交通运输和化工部门比重在转向欧盟消费偏好模式后略有提高,转向日本偏好模式后交通运输部门比重将提高,而金属部门比重将下降.受产业结构调整和能源效率提高的影响,中国未来能源消费总量呈倒U型趋势:在中国、欧盟、日本和美国消费偏好模式驱动下,能源消费总量依次下降,对应的能源高峰在2810～2166 Mtoe之间,累积排放量在94～72.6GtC之间.美国的消费偏好模式由于倾向于低碳的服务业部门,因此更有利于节能减排.     

A neighbor decay cellular automata approach for simulating urban expansion based on particle swarm intelligence

Simulation and quantitative analysis of urban land use change are effective ways to investigate urban form evolution. Cellular Automata (CA) has been used as a convenient and useful tool for simulating urban land use change. However, the key issue for CA models is the definition of the transition rules, and a number of statistical or artificial intelligence methods may be used to obtain the optimal rules. Neighborhood configuration is a basic component of transition rules, and is characterized by a distance decay effect. However, many CA models do not consider the neighbor decay effect in cellular space. This paper presents a neighbor decay cellular automata model based on particle swarm optimization (PSO-NDCA). We used particle swarm optimization (PSO) to find transition rules and considered the decay effect of the cellular neighborhood. A negative power exponential function was used to compute the decay coefficient of the cellular neighborhood in the model. By calculating the cumulative differences between simulation results and the sample data, the PSO automatically searched for the optimal combination of parameters of the transition rules. Using Xiamen City as a case study, we simulated urban land use changes for the periods 1992–1997 and 2002–2007. Results showed that the PSO-NDCA model had a higher prediction accuracy for built-up land, and a higher overall accuracy and Kappa coefficient than the urban CA model based on particle swarm optimization. The study demonstrates that there exist optimal neighborhood decay coefficients in accordance with the regional characteristics of an area. Urban CA modelling should take into account the role of neighborhood decay.     

巢湖流域土地优化利用技术集成框架初探

为实现湖泊资源合理、有效、可持续开发利用,优化岸线土地利用结构和空间配置,从土地管理实际需求出发,从方法论的视角构建了土地优化利用技术研发框架,提出了以多学科模型为基础的具有标准和向导两种交互模式的插件式集成框架,阐述了巢湖流域土地优化利用决策支持系统的总体架构、插件结构和工作原理。     

珠海市旅游用地生态优化研究

旅游用地生态优化是实现旅游用地持续利用与管理的重要途径。为弥补目前该领域关于时空布局和土地类型结构优化研究的不足,构建了基于生态适宜性和生态绿当量的ES-EGE(Ecological Suitability and Ecological Green Equivalent)旅游用地生态优化模型,包括时空优化配置模型和类型结构优化模型。借助3S技术,运用基于生态适宜性的旅游用地时空优化配置模型进行时空分析,得到珠海市旅游用地布局的生态适宜性分区图,未来依次布局西部生态适宜区内的康体休闲度假旅游用地项目、中部生态适宜区和生态较适宜区内的游乐、会展、游艇、高尔夫等特色旅游项目、东部生态较适宜区内特色岛屿的海洋休闲度假、运动游乐和生态休闲项目。现有旅游用地中,对已布局在生态非适宜区内的用地进行生态修复,将其中至少5.74%的建设用地调整为林地;运用基于生态绿当量的旅游用地类型结构优化模型分析计算,得出在土地利用类型结构方面,除将全部草地调整为林地外,还需将至少13.04hm2的建设用地调整为林地;综合时空优化配置模型和类型结构优化模型得出珠海市旅游用地生态优化结果空间分布图。建议生态非适宜区、生态较适宜区和生态适宜区建设用地所占比例分别不超过总用地面积的10.92%、15.13%%和52.48%。模型计算结果可为珠海市旅游用地生态优化与管理决策提供参考。     

水下滑翔器整体外形设计及水动力性能分析

对水下滑翔器的整体外形设计与水动力性能进行研究。在Slocum等几种典型水下滑翔器样机的基础上,对滑翔器的主体和附体进行一体化设计,得到阻力最小的新型水下滑翔器构型设计。利用CFD方法对水下滑翔器进行模拟仿真,通过分析对比五种主体构型,得到了比较合理的主体线型,然后用正交设计方法和曲线拟合法对附体进行了优选工作,最后得到了性能更优的整体载体外形。模拟仿真实验表明,滑翔器在8°左右攻角航行时,具有最大的升阻比;和Slocum等经典样机相比,新的载体具有更好的水动力性能。通过上述研究工作,也可以缩短水下滑翔器研制周期,降低设计成本,并为水下滑翔器的更优设计提供了有力的技术指导和参考。     

Fundamental behavior of Vortex Self Induced Vibration (VSIV)

An experimental facility has been designed to study the transverse response of the vortex-induced vibration of a fully submerged horizontal cylinder under the influence of vertical harmonic oscillating motion. The study aims to analyze the vortex self-induced vibration (VSIV) phenomenon which occurs on steel catenary risers (SCR) connected to floating platforms in the deep offshore. These vibrations occur in the absence of a current due to the self-motion of the body caused by a source afar. The experiments were conducted in a tank at the LOC/COPPE/UFRJ (Laboratory of Waves and Current of COPPE, Federal University of Rio de Janeiro). The amplitude and frequency of transverse motion are calculated for various Keulegan-Carpenter numbers and reduced velocities. Thanks to both the use of recent instrumentation and very low damping pneumatic bearing, the paper complements the pioneering work by Sumer and Fredsoe (1988) by exhibiting for the first time the trajectories of the VSIV motion. These are classified based on their different configurations such as oval-shape, eight-shape, etc. The Particle Image Velocimetry (PIV) tests are used to study the behavior of the flow around the cylinder during different trajectories of VSIV motion.     

Optimal Design of Equivalent Water Depth Truncated Mooring System Based on Baton Pattern Simulated Annealing Algorithm简

The highest similarity degree of static characteristics including both horizontal and vertical restoring force-displacement characteristics of total mooring system, as well as the tension-displacement characteristics of the representative single mooring line between the truncated and full depth system are obtained by annealing simulation algorithm for hybrid discrete variables （ASFHDV, in short）. A“baton” optimization approach is proposed by utilizing ASFHDV. After each baton of optimization, if a few dimensional variables reach the upper or lower limit, the boundary of certain dimensional variables shall be expanded. In consideration of the experimental requirements, the length of the upper mooring line should not be smaller than 8 m, and the diameter of the anchor chain on the bottom should be larger than 0.03 m. A 100000 t turret mooring FPSO in the water depth of 304 m, with the truncated water depth being 76 m, is taken as an example of equivalent water depth truncated mooring system optimal design and calculation, and is performed to obtain the conformation parameters of the truncated mooring system. The numerical results indicate that the present truncated mooring system design is successful and effective.