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111.
112.
Jan Frercks 《Studies in history and philosophy of science》2009,40(2):143-156
Ultraviolet radiation is generally considered to have been discovered by Johann Wilhelm Ritter in 1801. In this article, we study the reception of Ritter’s experiment during the first decade after the event—Ritter’s remaining lifetime. Drawing on the attributional model of discovery, we are interested in whether the German physicists and chemists granted Ritter’s observation the status of a discovery and, if so, of what. Two things are remarkable concerning the early reception, and both have to do more with neglect than with (positive) reception. Firstly, Ritter’s observation was sometimes accepted as a fact but, with the exception of C. J. B. Karsten’s theory of invisible light, it played almost no role in the lively debate about the nature of heat and light. We argue that it was the prevalent discourse based on the metaphysics of Stoffe that prevented a broader reception of Ritter’s invisible rays, not the fact that Ritter himself made his findings a part of his Naturphilosophie. Secondly, with the exception of C. E. Wünsch’s experiments on the visual spectrum, there was no experimental examination of the experiment. We argue that theorizing about ontological systems was more common than experimenting, because, given its social and institutional situation, this was the appropriate way of contributing to physics. Consequently, it was less clear in 1810 than in 1801 what, if anything, had been discovered by Ritter. 相似文献
113.
研究了复相 Cr2 O3 / Si C(M,Y) - Al2 O3 系稳定的高固相含量的低粘度悬浮体的流变特性 ,找出了影响流变性的主要因素。在碱性条件下 ,用实验室合成的 PMAA- NH4和 CM作为复合分散剂以及引入有机单体制备出固相含量高达 6 3(vol) % ,粘度为 2 35 m Pa.s的 Cr2 O3 /Si C(M,Y) - Al2 O3 悬浮体。 相似文献
114.
We examine consistency properties of the exchange rate expectation formation process of short‐run and long‐run forecasts in the dollar/euro and yen/dollar market. Applying nonlinear consistency restrictions we show that in a simple expectation formation structure short‐run forecasts are indeed inconsistent with long‐run predictions. Moreover, we establish a ‘twist’ in the dollar/euro expectation formation process, i.e. market participants expect bandwagon effects in the short run, while they have stabilizing expectations in their long‐run forecasts. Applying a panel probit analysis we find that this twisting behavior is more likely to occur in periods of excess exchange rate volatility. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Wu Xiong-bin Xu Ji-sheng Ma Shu-ying Tian Mao Yu Shen-bing K C Yeh W H Tsai K H Lin 《武汉大学学报:自然科学英文版》1999,4(2):186-192
The design and operation features of the automatic data acquisition system for the low-latitude ionospheric tomography along
the 120°E meridian are presented. The system, automatically collects the differential Doppler phase data, and GPS satellite
beacon signal is simultaneously collected to achieve time synchronization of all recelvers in whole station-chain. An improved
reconstruction algorithm of computerized ionospheric tomography is also proposed, in which calculating of the integral phase
constant and choosing of the initial guess are integrated in the procedure of reconstruction and evaluated by the reconstructed
image. Both numerical simulation examples and reconstructed results from observed data show that the new algorithm works reasonably
and effectively with ionospheric CT problems.
Foundation item: Supported by the National Natural Science Foundation of China (49584006)
Biography: WU Xiong-bin (1968-), male, Ph. D candidate. Research direction: computerized ionospheric tomography. 相似文献
117.
巴赫金的对话理论在戴维·洛奇的文学批评和小说创作方面都产生了深刻的影响,本文尝试从二元对立结构分析戴维·洛奇作品《想……》,解剖对话小说艺术在作品各个层面的运用。 相似文献
118.
Zhijing Lin Tingting Wang Dan Norback Haidong Kan Jan Sundell Zhuohui Zhao 《科学通报(英文版)》2014,59(35):5153-5160
In order to evaluate the perceived home indoor air quality, as well as sick building syndrome (SBS) in areas with typical arid continental climate such as Urumqi, northwest of China, a cross-sectional study including 4,260 parents of children (1-8 years) was performed by a ques- tionnaire survey in winter season in 2011. The sensation of air dryness (weekly/sometimes) in the last 3 months had the highest proportion of reports by more than half of the parents (57.4 %), followed by perceived stuffy odor (40.6 %), unpleasant odor (27.0 %), tobacco smoke odor (25.5 %), sensation of humid air (17.9 %), pungent odor (11.7 %) and moldy odor (9.5 %), respectively. The prevalence of SBS symptoms in the same time period was 40.4 % for general symptom, 47.7 % for mucosal symptom and 9.5 % for skin symptom, respectively. There were significant associations between perceived odors/sensation of air dryness and SBS symptoms (ORs range 1.39-1.42). Additionally, the OR values increased with an increase of the OH score (P 〈 0.05). Dampness, the presence of cockroaches and mosquitoes/flies, prenatal exposure to decoration and close to traffic were all risk factors of SBS symptoms. However, frequently putting bedding to sun- shine was potentially a protective factor. In conclusion, adults' perceptions of odors and sensation of air dryness are related to SBS symptoms and home environmental factors in Urumqi, China. 相似文献
119.
This study evaluated the prevalence and risk factors for asthma, allergy and related symptoms; and breastfeeding patterns and durations for 5479 Beijing children aged 3–6. Parents of children in randomly selected kindergartens wrote responses to a questionnaire used previously. The study aimed to evaluate trends in the prevalence of asthma and related illnesses, and to determine whether “more” breastfeeding, defined as exclusive, > 6 months, was associated with reduced prevalence. Asthma has increased in this age group between 1990 and 2011, with the steepest increase in the last 2–3 years. Of the total, 14.2% (779) children were breastfed exclusively for > 6 months. The efficacy of “more” breastfeeding was tested in a subset with two strong risk factors, positive family history (for asthma and/or allergy) and male gender. “More” breastfeeding was found to be significantly protective (aOR 0.42, P < 0.05) for this subset against Doctor-diagnosed asthma (D-asthma). Protection that did not reach statistical significance was also found for this subset against Wheeze ever, Cough at night, Rhinitis ever, Doctor-diagnosed rhinitis (D-rhinitis) and Eczema. The greatest protective effects were found for girls with no family history of asthma or allergy, reaching statistical significance for Wheeze ever (aOR 0.48, P < 0.01), Cough at night (aOR 0.47, P < 0.01), D-asthma (aOR 0.14, P < 0.01) and Rhinitis ever (aOR 0.67, P < 0.05). “More” breastfeeding was not consistently associated with either a protective or risk effect for Eczema. 相似文献
120.