变迁中的岛屿——韧性城市形态

以城市设计作为工具,对2种琶东开发方案下该地区所需的蓄洪量进行检验。琶洲岛位于中国珠江三角洲,地处广州中心地带的南部。琶洲岛因毗邻广州金融区,成为城市战略性发展的黄金地段;琶洲岛西部地区也成为互联网创新集聚区的一部分。根据目前琶洲岛东部地区的城市设计方案推测,未来琶东将会成为地域性的商业中心。因此,对2种发展方案进行对比,并分析2种方案预计可为暴雨时节提供的蓄水量,以及面临洪水和汹涌潮汐时所需要的保护措施。方案1将开发所有可用的土地,而方案2则将目前地势较低的场地作为暴雨期间可被淹没的湿地。基于1981—2017年间出现过的最大蓄洪量需求进行计算,并得出结论:百年一遇的雨洪可被储存于80 hm~2的现有低洼地带中,深1.34 m。最后,向地区政府提议,要求对琶洲岛周边地区进行适应性设计,以便进行防洪,并在低洼未建成区域进行适应性蓄水设计,免除方案1中建造昂贵蓄水装置的需求。还为岛上的村庄描绘了另一种未来蓝图,其中包括一个位于岛屿东南岸极易遭受台风和海浪灾害的渔村。     

片状洗涤剂(英)

讨论了片状洗涤剂的制备、特点及市场情况。片状洗涤剂在西欧市场取得成功 ,占领洗涤剂市场6 % ,并逐步进入美国和日本市场。     

DEVELOPMENT AND PRODUCTION OF FeAl BASED INTERMETALLIC ALLOYS

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城市山地保护：美国俄亥俄州辛辛那提市案例研究

记录了辛辛那提市自成立以来的发展历史,包括那些成为城市及其居民的长期财政负担的资源开发型的土地利用模式和不理智的工程实践。强调了过去40年里该市为缓解坡地不稳定性而采取的步骤,并提出了其他一些该市可以采取的关于未来山地开发的更为积极的措施。还记录了山地信托基金会（Hillside Trust）的工作,该基金会是一个成立于1976年的非营利组织,旨在倡导慎重利用和保护辛辛那提地区的山地。     

SELF-PROPAGATION HIGH-TEMPERATURE SYNTHESIS OF TiB_2-χAl COMPOSITE SYSTEM

研究了TiB_2-xAl复合体系的自蔓延高温合成(SHS)过程分析了组成、稀释剂含量对SHS过程的燃烧温度、燃烧波速度和试样体和变化的影响点火过程研究表明,点火温度影响点火持续时间、但不影响SHS本身的燃烧温度和燃烧波速度     

烟碱向降烟碱转化对烟叶麦斯明和TSNA含量的影响

以白肋烟TN90为材料,研究了非转化株、低转化株及高转化株烟叶样品的烟碱转化程度及降烟碱含量与烟叶麦斯明和烟草特有亚硝胺(TSNA)含量的关系。结果表明,随着烟株烟碱转化能力的提高和烟叶降烟碱含量的增加,叶片和主脉的麦斯明含量呈线性增加。当烟碱转化率超过20％时,麦斯明含量超过了假木贼碱的含量。在4种主要的TSNA中,具有不同烟碱转化能力的样品间4-(甲基亚硝胺基)-1-(3-吡啶基)-1-丁酮(NNK)、N-亚硝基新烟草碱(NAT)和N-亚硝基假木贼碱(NAB)含量没有显著差异,N-亚硝基降烟碱(NNN)含量则随着烟碱转化能力的提高和降烟碱含量的增加而大幅度升高,尤其在主脉中表现更为明显。NNN占总TSNA的比例随烟碱转化程度的提高而增加,在高转化烟株中可高达90％,其它3种TSNA占总TSNA的比例相应降低。叶片中NAT含量和比例一般高于NNK,而在主脉中NNK含量高于NAT。     

Zircon SHRIMP U-Pb geochronology,geochemistry and petrogenesis of the upper Eocene Shuangmaidi peraluminous granite in Baoshan Block,Western Yunnan Terrain,southwestern China

The Baoshan Block is tectonically located in the middle segment of the Sibumasu plate.Granitic magmatism within the Baoshan Block has been considered weakly active due mainly to very limited exposures during the Himalaya orogenic episode.The geochronological study on the buried Shuangmaidi granite has confirmed the existence of the Cenozoic granitoids in the Baoshan Block.The present study indicates that:(1) It is medium-to coarse-grained two mica phyric granite,characterized by high SiO 2 (73.55%-77.16%) a...     

效率为98%的单相和三相单级交流一直流变换器拓扑结构

目前在电力电子技术研究领域,具有隔离和功率因数校正功能的单级AC-DC变换器,均是依赖于全桥整流的新型变换器。当前的单相AC-DC变换器是基于传统的脉宽调制(PWM)变换方法实现的,它至少包括3个不同的功率信号处理级:全桥整流器、BOOST PFC变换器和串联隔离式全桥DC-DC变换器,共用到14个开关器件和3个磁性元件,这些都对变换器的效率、尺寸和成本限制产生影响。本文所介绍的混合变换方法,实现了一种新型单级AC-DC变换器拓扑结构,是一种只包括3个开关器件和1个磁性元件的非桥型PFC变换器。这种变换器具有98%左右的效率、0.999的功率因数和总共仅1.7%的谐波畸变。三相整流器包含了3个这样的单相整流器,它利用了特斯拉三相转换系统的优点,可以进行三相系统的输入功率到直流输出功率的瞬态转换,具有高频光隔离,0.999的功率因数,低谐波畸变(1.7%),较小的尺寸和成本等特点,而且效率达到了98%。。     

Functional anatomy of musical processing in listeners with absolute pitch and relative pitch

We used both structural and functional brain imaging techniques to investigate the neural basis of absolute pitch (AP), a specialized skill present in some musicians. By using positron emission tomography, we measured cerebral blood flow during the presentation of musical tones to AP possessors and to control musicians without AP. Listening to musical tones resulted in similar patterns of increased cerebral blood flow in auditory cortical areas in both groups, as expected. The AP group also demonstrated activation of the left posterior dorsolateral frontal cortex, an area thought to be related to learning conditional associations. However, a similar pattern of left dorsolateral frontal activity was also observed in non-AP subjects when they made relative pitch judgments of intervals, such as minor or major. Conversely, activity within the right inferior frontal cortex was observed in control but not in AP subjects during the interval-judgment task, suggesting that AP possessors need not access working memory mechanisms in this task. MRI measures of cortical volume indicated a larger left planum temporale in the AP group, which correlated with performance on an pitch-naming task. Our findings suggest that AP may not be associated with a unique pattern of cerebral activity but rather may depend on the recruitment of a specialized network involved in the retrieval and manipulation of verbal-tonal associations.     

Combining Aluminum Heat Treat with Hot Isostatic Pressing: A Comparison of Structure, Properties, and Processing Routes for a Cast AI-Si-Mg Alloy

WHEN CAST ALUMINUM COMPONENTS are usedin applications which require high strength,a T6heattreatment is often employed to bring the castings to amaximum strength condition.This heat treatmentconsists of three steps:a solution heat treatment,duringwhich the large deleterious phases which have formedduring solidification are dissolved into a solid solution;quenching,to produce a supersaturated solid solution;and an aging treatment which yields a microstructureconsisting of a fine array …