三维有序大孔材料应用研究进展

三维有序大孔(3DOM)材料兼有有序大孔结构和固体材料本身两种特性,受到人们普遍关注.介绍了3DOM材料结构,并综述了近年来3DOM材料的应用研究,如作为催化材料、载体、电极材料、传感器、光子晶体和磁性材料等;对3DOM材料未来的发展做出了展望.     

山西省城镇化质量与城镇化规模的实证分析

城镇化质量与城镇化规模是城镇化内部机制的两个关键因素,两者的协调性决定了城镇化效果的优劣,对城镇化质量与规模的发展状况以及两者之间的协调关系进行分析研究具有重要意义。本文构建评价指标体系对山西省11个地级市的城镇化质量与规模进行测度,并分析两者的协调关系,结果表明:1.山西省各城市的城镇化质量不断提升,城镇化规模不断扩大,特别在2007年以后,质量与规模的增长均明显加快。2.山西省各地级市的城镇化水平由低水平向中等水平发展,城镇化质量与规模偏离情况的变化有所不同。3.山西省城镇化质量与规模协调关系存在明显的空间分异,两者偏离程度逐年扩大。     

国内城市规划关于不确定性研究综述

按时间顺序简述国内城市规划关于不确定性问题的研究状况,对部分内容作简单评价。从时间角度看,研究主题经历了从必要性、实际问题、规划方法体系到专题研究的变化过程。应对不确定性的方法可归纳为以下几种主要形式:动态规划、增加规划弹性、目标和共识框架形式、利用城市自组织、数理模型方法以及改善规划过程等。将这些方法的思想本质解读为"扩展智力作用空间"。     

Seasonal and diurnal variations of carbonyl compounds in the urban atmosphere of Guangzhou, China

Seasonal and diurnal variations of carbonyl compounds were investigated at two sampling sites (Liwan and Wushan) in the ambient air of Guangzhou, China. Air samples were collected during 2005 from January to November, and carbonyl compounds were analyzed with HPLC. The results show that carbonyls exhibit distinct seasonal variation. The total concentrations of 21 carbonyls detected ranged from 2.64 to 103.6 μg m⁻³ at Liwan and from 5.46 to 89.9 μg m⁻³ at Wushan, respectively. The average total concentrations of carbonyls at both Liwan and Wushan decreased in order of summer>spring>autumn>winter. Formaldehyde, acetaldehyde, and acetone were the most abundant carbonyl compounds, which accounted for more than 60% of the total concentrations of carbonyls. The mean concentration ratios of summer/winter were all > 1.0 for the total concentrations and the individual carbonyl compound. The diurnal variation of carbonyls was not distinct in this study. The average concentration ratios of formaldehyde/acetaldehyde (C₁/C₂) varied from 0.71 to 1.32 and 0.65 to 1.14 at Liwan and Wushan, respectively, and the average concentration ratios of acetaldehyde/propionaldehyde (C₂/C₃) varied from 5.42 to 7.70 and 5.02 to 13.9 in Liwan and Wushan, respectively. Regarding photochemical reactivity of carbonyls and the ozone production, acetaldehyde, butyraldehyde, formaldehyde, and valeraldehyde account for 75-90% to the total propene-equivalent concentrations, while formaldehyde, acetaldehyde, valeraldehyde, butyraldehyde, and propionaldehyde contribute 89-96% to the total ozone formation potentials (ranging from 105 to 274 μg m^-3). The ozone formation potentials in summer were higher by 1-2 times than those in the other seasons.     

PIN型非晶硅薄膜太阳电池仿真研究

运用AMPS软件,对TCO/p-a-SiC:H/i-a-Si:H/n-a-Si:H/metal型非晶硅薄膜太阳电池进行了仿真研究,重点模拟和分析了电池性能参数随i层和n层厚度变化的规律.结果表明,为了获得电池转换效率和短路电流密度的最大值,n 层非晶硅薄膜应尽可能地减小厚度,而i层非晶硅薄膜厚度最好控制在500～700 nm范围内.     

a-Si:H薄膜的磷-碳二元复合掺杂改性研究

以SiH4,PH3,CH4为源气体,采用射频等离子增强化学气相沉积(RF-PECVD)方法,通过改变CH4流量制备了磷、碳二元掺杂非晶硅薄膜,研究了磷、碳二元掺杂对薄膜微观结构和光学性能的影响.用X射线光电子能谱仪(XPS)观察到了C-Si峰的存在,同时发现随着CH4流量的增加,薄膜中C元素含量逐渐增大.傅里叶转换红外光谱(FTIR)测试表明,掺杂薄膜中的H含量随着CH4流量的增加逐渐增大,由11.5%增大到24.6%.光学性能测试表明,随着CH4流量的增加,掺杂薄膜的折射率逐渐降低,而光学带隙逐渐增加.     

基于ZigBee的无线温湿度采集系统研究

针对目前的温湿度采集系统存在的高功耗和自组网等问题,组建一种低功耗通用的无线数据采集系统;然后介绍了ZigBee无线传输协议和所选硬件的特点,着重分析了ZigBee无线传感网络的体系结构,给出了以CC2430片上系统芯片为核心的无线网络系统的硬件构成以及主节点的设计和工作流程;最后,制作的硬件结构调试结果表明,利用所选部件搭建的网络可实现良好的自组网性,提高了系统可扩展性,达到节能延寿的目的。     

经肱三头肌两侧入路双钢板内固定治疗肱骨髁间粉碎骨折21例体会

目的评价经肱三头肌两侧入路双钢板治疗肱骨髁间粉碎骨折的临床疗效。方法对21例AO分型为C型的肱骨髁间粉碎骨折患者采用经肱三头肌两侧入路实施手术治疗,应用双钢板内固定,术后早期行功能锻炼。结果随访时间:13～31个月,平均20个月。无血管神经损伤,切口感染,内固定松动断裂等并发症。骨折全部愈合,骨折愈合时间平均为4.5个月。按Cassebaum评分系统评分,优5例,良13例,差3例,优良率达85.7%。结论采用经肱三头肌两侧入路创伤小,双钢板内固定稳定可靠,肘关节功能恢复满意。     

隧洞开挖过程中渗透破坏细观机制研究

渗透破坏是隧洞施工过程中面临的一类重要的工程灾害问题,对隧洞渗透破坏机制的研究可应用于隧道施工安全预报.利用颗粒流法在模拟散体及破碎介质方面的优势,结合流体动力学数值模拟的有限体积法,建立由黏结颗粒材料组成岩块的二维数值模型,模拟储水断层中不同的水压力时,隧洞开挖引起的渗透破坏现象,模拟过程可以实时反映开挖过程中微裂隙的扩展及渗透张量的变化.模拟结果表明,颗粒流法模拟岩体渗透破坏过程是可行的,对于隧洞工程开挖具有一定的指导意义.     

Footholds optimization for legged robots walking on complex terrain

This paper proposes a novel continuous footholds optimization method for legged robots to expand their walking ability on complex terrains. The algorithm can efficiently run onboard and online by using terrain perception information to protect the robot against slipping or tripping on the edge of obstacles, and to improve its stability and safety when walking on complex terrain. By relying on the depth camera installed on the robot and obtaining the terrain heightmap, the algorithm converts the discrete grid heightmap into a continuous costmap. Then, it constructs an optimization function combined with the robot’s state information to select the next footholds and generate the motion trajectory to control the robot’s locomotion. Compared with most existing footholds selection algorithms that rely on discrete enumeration search, as far as we know, the proposed algorithm is the first to use a continuous optimization method. We successfully implemented the algorithm on a hexapod robot, and verified its feasibility in a walking experiment on a complex terrain.