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71.
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CHARLES H. SMITH 《国际通用系统杂志》2013,42(4):385-400
The emphasis in this work is on the practical application of ideas set forth in Part I. Two studies involving spatial distribution are discussed: the distribution of human population in the Indianapolis, Indiana Region, and the world distribution of mammals. In the first, populations over the period 1890–1980 of Ihe 393 townships making up the study area are used to produce classifications involving various numbers of classes of township types. A test of the theoretical structure posed in Part I is then detailed. On the theory that the underlying relations involved cannot sustain a real world structure involving more than five functional classes, it is hypothesized that classifications involving more than five classes will be associated with township distribution patterns that conflict with Central Place Theory. This is shown to be clearly so. In the second study, the derivation of a five region partitioning of world mammalian distribution patterns is described. Discussion includes the introduction of a wholly new rationale for taxonomic revision based on biogeographic criteria (and ultimately the principles described in Part I). The study closes with a short argument regarding why the model described in Part I should not be labelled as either social physics or anti-humanistic. 相似文献
74.
余东古镇空间结构研究 总被引:1,自引:0,他引:1
余东,古称“凤城”是南通海门境内为数不多有城池的千年古镇。四面环绕的护城河、类似凤凰展翅的总体布局形成的古镇自然空间显示着古镇选址的意涵和营造的独具匠心;延伸至南门外的南北大街和众多的东西向小巷形成鱼骨状的街道布局,特殊的环境造就典型的江北水空间特征,具有商业、居住、宗教的功能建筑以及类型丰富的街道界面和古镇肌理变化形成的物质空间彰显着千年古镇昔日的地位和繁华。 相似文献
75.
TARIQ MASUD SHABANA MAQSOOD SHEHLA SAMMI 《International Journal of Dairy Technology》2011,64(3):433-436
Bacteriophages of Lactococcus lactis ssp. diacetylactis isolated in Pakistan and Germany were compared in respect of protein profile and restriction analysis. SDS‐PAGE profile analysis shows similarities amongst the local isolates that have different protein profile when compared with phages from other regions. No marked difference was observed in their DNA homology. The data suggested that the bacteriophages isolated from Pakistan are different from the bacteriophages that have already been characterised from the other parts of the world. 相似文献
76.
《Ergonomics》2012,55(2):178-191
The study investigated the natural work–pause pattern of computer users and the possible effects of imposing pause regimes on this pattern. Hereto, the precise timing of computer events was recorded across a large number of days. It was found that the distribution of the pause durations was extremely skewed and that pauses with twice the duration are twice less likely to occur. The effects of imposing pause regimes were studied by performing a simulation of commercially available pause software. It was found that depending on the duration of the introduced pause, the software added 25–57% of the pauses taken naturally. Analysis of the timing of the introduced pauses revealed that a large number of spontaneous pauses were taken close to the inserted pause. Considering the disappointing results of studies investigating the effects of introducing (active) pauses during computer work, this study has cast doubt on the usefulness of introducing short duration pauses. 相似文献
77.
介绍一种新型镶嵌式组合结构催化剂挤条成型装置。新型镶嵌式催化剂挤条成型装置的模架为不锈钢材料,镶嵌模块采用工程塑料,模块更换方便,催化剂挤出顺畅,能满足石化行业催化剂挤条生产中耐温、耐压、耐腐蚀以及规模化生产的要求。与不锈钢整体结构挤条模板相比,新型镶嵌式催化剂成型装置不仅成本降低较大,而且制作周期缩短。 相似文献
78.
新型电励磁磁通切换电机励磁绕组结构分析 总被引:1,自引:0,他引:1
励磁绕组连接方式对电励磁磁通切换电机电磁特性影响很大。对所提出的2种新型电励磁磁通切换电机,分析了其工作模式和“磁通切换原理”,利用有限元分析方法比较了2种电机的电磁特性:定子磁链、反电势、气隙磁密、定位力矩、电磁转矩、转矩密度。重点比较了励磁绕组连接方式对电机漏磁和功率密度的影响。结果表明,电励磁磁通切换电机具有较高正弦度的双极性磁链和全周期工作模式,适合运行在无刷交流场合。拓扑2具有更小的漏磁和更高的励磁电流利用率,其转矩密度为拓扑1的2倍。分析结果为所提出电励磁磁通切换电机在航空起动/发电机系统、风力发电系统等领域的应用提供了理论背景。 相似文献
79.
80.
B. Degroote T. Vandeweyer N. Collaert W. Boullart E. Kunnen D. Shamiryan J. Wouters J. Van Puymbroeck A. Dixit M. Jurczak 《Microelectronic Engineering》2007,84(4):609-618
We present a method to obtain Si-fins with a critical dimension (CD) below 20 nm, separated by a minimum distance of 25 nm and connected by a common source/drain (S/D) pad. The method comprises of recursive spacer defined patterning to quadruple the line density of a 350 nm pitch resist pattern defined by 193 nm lithography. Spacer defined patterning is combined with resist based patterning to simultaneously define fins and S/D pads in a Silicon on Insulator (SOI) film. CD and Line Width Roughness (LWR) analysis was done on top down SEM images taken in a center die and in an edge die of a 200 mm wafer. The average CD is 17 nm in the center of the wafer and 18 nm at the edge. The LWR is 3 nm for both center and edge. Additional process steps to remove etch damage and round the top corner of the fin (i.e. oxidation followed by H2 anneal) further reduce the CD to 13 nm. 相似文献