The impact of electric overhead radiant heating on the indoor environment of historic churches     

Lucyna Samek  Anna De Maeyer-Worobiec  Zoya Spolnik  Lszl Bencs  Velichka Kontozova  &#x;ukasz Bratasz  Roman Koz&#x;owski  Ren Van Grieken 《Journal of Cultural Heritage》2007,8(4):361-369

The impact of electric overhead radiant heaters on the microclimate, air flows, transport and deposition of suspended particulate matter (SPM) was monitored between March 2004 and March 2005 in the historic churches of Saint Michael Archangel in Szalowa and Saint Catherine in Cracow (Poland). The measurements show that although irradiation at the floor level increases temperature and reduces relative humidity in the interior of the church, the effect out of the heated zone and for the surfaces sheltered from irradiation is very limited, i.e. their extent is comparable with natural fluctuations inherent to the local climate of the church. The radiant heaters proved to generate little convectional flow of the air. Therefore, the heating system was not found to increase the concentration of SPM indoors; in particular, no re-suspension of particles already present in the church was observed. This work has demonstrated that the overhead radiant heaters are capable of providing localised heat to the areas where people congregate without adversely affecting painted walls and the works of arts displayed in churches. Care, however, should be taken that sensitive works of art are not exposed to the direct infrared radiation.  相似文献   

数风流人物还看今朝--第47届世乒赛综述     

汪伟信 《安徽体育科技》2003,24(4):21-22

中国队乒乓球在世界乒坛中的整体领先实力短期内难以逆转，但通过国际乒联对现行乒乓球比赛规则的不断修改，将会对中国乒乓球的霸主地位形或新一轮的冲击。通过对第47届世界乒乓球锦标赛的剖析，一个新老交替、打法多样、风格各异的发展格局已见端倪。  相似文献   

A construct‐modeling approach to develop a learning progression of how students understand the structure of matter     

《科学教学研究杂志》2017,54(8):1024-1048

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原子核的中子皮厚度与非对称核物质态方程     

刘敏  李祝霞 《中国科学院研究生院学报》2007,24(2):167-173

挑选47组常用的Skyrme参数，采用Skyrme能量密度泛函结合拓展的Thomas－Fermi展开，用约束的密度变分法，我们计算了208Pb、112~124Sn 、 48Ca 、 96Zr、18O 等丰中子核的中子皮厚度并与实验数据分析抽取的中子皮厚度比较，研究了中子皮厚度与非对称核物质态方程中同位旋相关的对称能项之间的关系。我们发现中子皮厚度随对称能系数 a s 以及对称能在饱和密度附近的斜率L、曲率Ksym的增大呈现近似的线性增大的趋势，对称能越硬的核势确定的中子皮越厚。以反质子湮灭法拟合的参考实验值作为标准，我们给出对称能系数，对称能在饱和密度附近的斜率和曲率的参考范围分别为：as = 30 ~ 35MeV ，L = 20 ~ 100MeV，Ksym = -256 ~ 70MeV。满足这个条件的Skyrme 参数有：SLy0-SLy10、SkM*、SkP、SLy230a、SkMP、SKT1-3、SkI3、MSk1-2、SII 。  相似文献   

小叶章湿地土壤可利用性碳对微生物呼吸的限制作用--三江平原为例   总被引：1，自引：0，他引：1  

徐小锋  宋长春  宋霞 《中国科学院研究生院学报》2004,21(4):538-542

研究了三江平原小叶章湿地土壤中碳的可利用性对土壤中微生物呼吸的限制作用 .结果表明 ,表土和根层土中的可利用性碳显著限制微生物呼吸作用 .在所有的培养土壤中 ,起始时微生物呼吸速率较高 ,随之急剧下降 ,这可能是由于土壤物理化学及生物性质的变化所致 .土壤中有机质低于 1 0 %时 ,可以明显影响碳的可利用指数 ;大于 1 0 %以后就几乎没有影响了 .微生物生物量碳与碳的可利用指数也存在较为显著的正相关关系 .  相似文献   

AEROTEL LTD v TELCO HOLDINGS LTD MACROSSAN'S PATENT APPLICATION     

Court of Appeal   《RPC》2007,124(4):117-161

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天文与天体物理研究现状及未来发展的战略思考          下载免费PDF全文

严俊 《中国科学院院刊》2011,26(5):487-495

文章阐述了天文学科发展背景和研究意义,综述了近10多年来国内外天文学研究的重大进展,以及未来国际天文学发展所面临主要学科问题。对比了中外天文设备发展的状态和差距,探讨了中国天文科技发展的战略举措,最后对中国天文科技整体发展提出了一些建议。  相似文献   

松嫩平原土壤有机质含量高光谱反演研究   总被引：7，自引：0，他引：7  

武彦清  张柏  宋开山  刘焕军  王宗明  刘殿伟 《中国科学院研究生院学报》2011,28(2)

采集松嫩平原典型类型土壤样本252个.室内条件下测定了风干后土样的光谱.对原始光谱数据作预处理后,分别运用多元线性逐步回归法和偏最小二乘法建立土壤有机质含量高光谱预测模型.结果表明,采用2种方法建立的模型均可满足有机质含量速测要求,但偏最小二乘法得到的模型更具稳健性.  相似文献   

腐殖酸对富勒烯C60的悬浮作用     

Lu-qing ZHANG  ;Yu-kun ZHANG  ;Xiu-chun LIN  ;Kun YANG  ;Dao-hui LIN 《浙江大学学报(A卷英文版)》2014,15(8):634-642

研究目的：腐殖酸（HA）对富勒烯（C60）粉末的悬浮作用以及pH、离子强度对HA-C60悬浮性能的影响。创新要点：研究水质条件对C60悬浮性能的影响。研究方法：测定C60粉末在HA溶液中的zeta电位,水力学粒径和悬浮浓度;HA存在下,C60悬浮体系的zeta电位与水力学粒径随pH的变化及C60悬浮体系团聚动力学随离子强度的变化。重要结论：HA对C60粉末起到一定的分散作用,但不能使其长时间稳定悬浮于水中。当pH〈4时,C60水悬液开始沉淀;而当HA存在时,C60水悬液在pH 3-11范围内都保持稳定,这是由于HA吸附于C60表面,通过静电排斥和空间位阻作用,促进C60分散悬浮。C60水悬液的稳定性随盐离子价位和浓度升高而降低。HA会抑制Na＋对C60水悬液的脱稳作用;但高价离子Ca2＋和La3＋存在时,HA与C60之间会发生桥联从而促进C60水悬液脱稳沉淀。  相似文献   

Combining fiber dissection,plastination, and tractography for neuroanatomical education: Revealing the cerebellar nuclei and their white matter connections          下载免费PDF全文

Hisse Arnts  Michiel Kleinnijenhuis  Jan G.M. Kooloos  Annelieke N. Schepens‐Franke  Anne‐Marie van Cappellen van Walsum 《Anatomical sciences education》2014,7(1):47-55

In recent years, there has been a growing interest in white matter anatomy of the human brain. With advances in brain imaging techniques, the significance of white matter integrity for brain function has been demonstrated in various neurological and psychiatric disorders. As the demand for interpretation of clinical and imaging data on white matter increases, the needs for white matter anatomy education are changing. Because cross‐sectional images and formalin‐fixed brain specimens are often insufficient in visualizing the complexity of three‐dimensional (3D) white matter anatomy, obtaining a comprehensible conception of fiber tract morphology can be difficult. Fiber dissection is a technique that allows isolation of whole fiber pathways, revealing 3D structural and functional relationships of white matter in the human brain. In this study, we describe the use of fiber dissection in combination with plastination to obtain durable and easy to use 3D white matter specimens that do not require special care or conditions. The specimens can be used as a tool in teaching white matter anatomy and structural connectivity. We included four human brains and show a series of white matter specimens of both cerebrum and cerebellum focusing on the cerebellar nuclei and associated white matter tracts, as these are especially difficult to visualize in two‐dimensional specimens and demonstrate preservation of detailed human anatomy. Finally, we describe how the integration of white matter specimens with radiological information of new brain imaging techniques such as diffusion tensor imaging tractography can be used in teaching modern neuroanatomy with emphasis on structural connectivity. Anat Sci Educ. 7: 47–55. © 2013 American Association of Anatomists.  相似文献