High-sensitivity and wide-directivity ultrasound detection using high Q polymer microring resonators

Small size ultrahigh Q polymer microrings working at near visible wavelength have been experimentally demonstrated as ultralow noise ultrasound detectors with wide directivity at high frequencies (>20 MHz). By combining a resist reflow and a low bias continuous etching and passivation process in mold fabrication, imprinted polymer microrings with drastically improved sidewall smoothness were obtained. An ultralow noise-equivalent pressure of 21.4 Pa over 1-75 MHz range has been achieved using a fabricated detector of 60 μm diameter. The device's wide acceptance angle with high sensitivity considerably benefits ultrasound-related imaging.     

How China tackles climate change through standards

Climate change is a challenge faced by the whole humanity.As the world's largest developing country, China attaches great importance to climate change and has taken effective measures to address climate change issues despite its tremendous task to develop economy, eliminate poverty and improve people's livelihood.     

On numerical experiments for Cauchy problems of elliptic operators

Over the last decade, there has been a considerable amount of new numerical methods being developed for solving the Cauchy problems of elliptic operators. In this paper, with some new classes of numerical experiments, we re-verify the conclusions in the review article [Wei T, Hon YC, Ling L. Method of fundamental solutions with regularization techniques for Cauchy problems of elliptic operators. Eng Anal Bound Elem 2007;31(4):373–85.] concerning the effectiveness of solving Cauchy problems with the method of fundamental solutions.     

无线传感器网络中d-Hop 2-连通容错支配集的分布式构造算法

无线传感器网络随节点移动组成自我维持的自组织系统,采用连通支配集的虚拟骨干技术可使平面网络系统层次化而简化节点路由、管理和维护。但大规模无线传感器网络的连通支配集节点数目依然庞大,d-hop连通支配集可以大大减小支配集节点数目。另外,由于存在节点失效、链路断裂等无线特性,虚拟骨干网需要具备一定的容错性。在单位圆盘图网络模型中为构建精简且具有容错能力的虚拟骨干网,提出d-hop 2-连通支配集的分布式构造算法,先构造d-hop独立支配集后再连通形成d-hop 2-连通支配集。并从理论和仿真上对算法的复杂度、近似比和算法性能作了进一步探讨和验证。     

煤制乙二醇技术进展

综述了目前乙二醇生产工艺技术的现状和发展动向,指出了石油乙烯路线是目前乙二醇工业生产的主要工艺。同时,着重介绍了中国科学院福建物质结构研究所与企业合作,率先在国内外实现工业化的煤制乙二醇的成套技术。该技术符合我国缺油、少气、煤炭资源相对丰富的资源特点,可利用煤炭资源生产乙二醇,代替目前的石油乙烯路线,将有效缓解我国乙二醇产品供需矛盾,逐步实现我国以煤代油生产乙二醇的战略目标,节省大量石油资源,对国家的能源和化工产业产生重要积极影响,代表了当今煤化工领域的前沿发展方向之一。     

磁极线圈铜排钨极氩弧焊焊接工艺改进

通过对T2纯铜进行焊接性分析,对厚截面磁极线圈T2铜排的TIG焊接工艺进行合理的改进。通过改进,实现了厚截面T2铜排不需高温预热就可进行TIG焊接,并经外观检查、渗透探伤及力学性能检验,各项指标均合格,达到标准要求。     

道面水泥混凝土粗集料分形特征

为了分析道面水泥混凝土粗集料的分形特征,基于分形几何的基本理论,推导出了集料的质量分布分形几何模型;针对军用机场水泥混凝土道面粗集料的特点,分析了集料分维数D的计算方法,并按筛孔19.0 mm的通过量确定最小计算粒径;分维数越大,级配中的细颗粒就越多;随着分维数D的增大,水泥混凝土的抗弯拉强度也相应地增大。     

关于人工岛设计中的研究方法探讨

该文以海口市新埠岛概念性详细规划投标方案为例,浅谈在城市设计过程中人工岛设计所应关注的研究方面和设计程序;探讨在今后的海岛设计中越来越多牵扯到填海或海岸线整治方面的情况时,如何有效地进行定位研究,以推导出更合理的设计方案。     

牵引用铅酸蓄电池负极板活性物质过早脱落的原因分析

就目前市场上牵引用铅酸蓄电池负极板活性物质过早脱落而使寿命不足一年的问题,经实车运行和试验台两方面试验及正极板添加剂对比实验得出,在正极板中加入一定量的红丹有助于正极板化成,可使蓄电池初期容量较好,延长使用寿命;正极板中的添加剂活性碳是影响负极板膨胀的主要原因。