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1.
风能技术发展中的几个问题   总被引:6,自引:0,他引:6  
改善能源结构,利用可再生能源,减轻环境污染,提高人民生活质量,已成了全球能源工业关注的一个热点,风能是目前最有开发利用前景和技术最成熟的一种新能源和可再生能源之一。随着风能开发和利用的发展,风能技术也取得了显著的进步,并逐渐成为能源技术中的一个分支。本文简要介绍当前风能技术发展中的几个关注的问题。  相似文献   

2.
Summary The free energy of unfolding of several myoglobins from different animal species has been determined from their denatunation pattern by using the ligand binding model. The results indicate that no simple correlation exists between the free energy of unfolding of myoglobin and the basal metabolic rate of the animal species from which the myoglobin was isolated  相似文献   

3.
The free energy of unfolding of several myoglobins from different animal species has been determined from their denaturation pattern by using the ligand binding model. The results indicate that no simple correlation exists between the free energy of unfolding of myoglobin and the basal metabolic rate of the animal species from which the myoglobin was isolated.  相似文献   

4.
Summary Disturbance to energy production in the S180 sarcoma (CB) by optical isomers of isoproterenol was assessed from altered adenine nucleotide levels at 1 h. The L-isomer almost halved the ATP level and lowered the energy charge significantly; the D-isomer was inactive. Dependence of tumor injury on cytochrome P-450 activity appears unlikely.One of us (GRNJ) thanks the Department of Surgery, Medical School, Kings's College Hospital, London, England, for the provision of experimental facilities; the Institute of Biochemistry, German Cancer Research Centre, Heidelberg, FRG, for permitting the measurement of metabolites; the Cancer Research Campaign, London, UK, for a part-time grant; and Zyma GmbH, München, FRG, and the estate of the late Dr Lucie Polak for additional financial support.  相似文献   

5.
螺旋钻采煤机螺旋钻杆失稳条件研究   总被引:1,自引:0,他引:1  
通过考虑动能和势能对螺旋钻杆屈曲的影响,运用能量法研究了螺旋钻杆最大转速与螺旋屈曲时临界轴向力间的关系,建立了螺旋钻杆和轴向临界力间的数学模型。研究表明:螺旋钻杆的失稳条件符合实际,对螺旋钻采煤机设计具有十分重要的指导意义。  相似文献   

6.
能源问题是当今世界的热点问题之一。作为最重要的可再生清洁能源之一,氢能是解决当前能源危机的重要途径之一。本文综述了电解水制氢原理和目前电解水制氢的发展现状,并预测了电催化分解水制氢的发展与应用前景。  相似文献   

7.
利用FLAC模拟了不同围压下圆形巷道围岩岩爆过程中的声发射及能量释放过程。利用8个FISH函数开挖巷道,统计破坏单元数目及破坏单元在应变软化阶段的能量释放总量和能量释放率。模拟分为3步:首先,将静水压力施加在模型上,直到达到静力平衡状态;然后开挖巷道;最后,重新计算,直到达到静力平衡状态或者塑性流动状态。模拟结果表明,当围压较高时,开挖巷道后的围岩的声发射活动呈现间歇式上升特征;而当围压较低时,开挖巷道后的围岩中的声发射活动最终趋于平静;随着围压的增加,能量释放现象出现得早些,声发射累计数、释放的弹性应变能都增加。在开挖巷道后的围岩中,发生剪破坏的单元释放的弹性应变能总量大于发生拉破坏的,最高的剪应变能释放率大于最高的拉应变能释放率。  相似文献   

8.
Scientism applies the ideas and methods of the natural sciences to the humanities and social sciences. Herbert Spencer applied the law of the conservation of energy to social questions and arrived at formula answers to the issues of the day. The kind of certitude that Spencer aimed for was possible only by ignoring a system of values. Much as he may have believed that he was above personal beliefs, there are values implicit in Spencer's theories and they are the values of the nineteenth-century British middle class. Reasoning by analogy is as valid in social theory as it is in the natural sciences. Spencer's error was in universally applying the idea of the conservation of energy to social systems by means of identity rather than by analogy. Scientists in Britain, where there was a self-assured scientific community, dismissed Spencer's theories as being unscientific, but he enjoyed a vogue in the United States.  相似文献   

9.
Using a newly developed microcalorimetric approach to assess the rate of energy expenditure for intracellular [Ca2+] homeostasis in isolated muscles at rest, we found this was lower inmdx than in control mouse muscles, by 62% and 29% in soleus and extensor digitorum longus, respectively. Differences in total and Ca2+-dependent rates of specific heat production betweenmdx and control were enhanced during sustained, KCl-induced stimulation of energy dissipation. These results suggest that the low sacroplasmic energy status of dystrophic muscles is not due to any excessive energy expenditure for intracellular [Ca2+] homeostasis.  相似文献   

10.
Energy expenditure was investigated in 15 patients with liver cirrhosis and 20 healthy controls by three methods: indirect calorimetry, anthropometry using the Harris-Benedict equation and bioelectrical impedance analysis. The energy expenditure was expressed in kcal/day, kcal/kg BW/day (BW — body weight), kcal/kg LBM/day (LBM — lean body mass, derived by bioelectrical impedance analysis) or in kcal/m2/day. We did not find statistical differences between values of resting energy expenditure obtained in patients with cirrhosis of the liver and healthy controls whichever method we used. We also did not find statistical differences between values obtained by indirect calorimetry, anthropometry and bioelectrical impedance analysis. There was a significant correlation between indirect calorimetry and anthropometry in both groups. We found significant correlations between indirect calorimetry and anthropometry, and between indirect calorimetry and bioelectrical impedance analysis, in the control group only. We can conclude that (1) resting energy expenditure of patients with cirrhosis of the liver is not changed when compared with healthy controls, and (2) bioelectrical impedance is a useful method to calculate body composition from which energy expenditure is derived; however, it gives an appropriate result only in healthy people, and only approximate values in patients with cirrhosis.  相似文献   

11.
Tight junctions seal intercellular clefts via membrane-related strands, hence, maintaining important organ functions. We investigated the self-association of strand-forming transmembrane tight junction proteins. The regulatory tight junction protein occludin was differently tagged and cotransfected in eucaryotic cells. These occludins colocalized within the plasma membrane of the same cell, coprecipitated and exhibited fluorescence resonance energy transfer. Differently tagged strand-forming claudin-5 also colocalized in the plasma membrane of the same cell and showed fluorescence resonance energy transfer. This demonstrates self-association in intact cells both of occludin and claudin-5 in one plasma membrane. In search of dimerizing regions of occludin, dimerization of its cytosolic C-terminal coiledcoil domain was identified. In claudin-5, the second extracellular loop was detected as a dimer. Since the transmembrane junctional adhesion molecule also is known to dimerize, the assumption that homodimerization of transmembrane tight junction proteins may serve as a common structural feature in tight junction assembly is supported. Received 6 October 2005; received after revision 14 December 2005; accepted 27 December 2005 †These authors contributed equally to this work.  相似文献   

12.
Summary A microbiol culture able to grow in the absence of oxygen with nitrilotriacetate (NTA) as the sole source of carbon and energy was enriched from river sediment. Growth was strictly dependent on the presence of nitrate and the results indicate that nitrate was exclusively used as the electron acceptor and was reduced to dinitrogen (N2). The stoichiometry of anaerobic NTA degradation by the enrichment culture was determined.  相似文献   

13.
D R Passino  G W Brown 《Experientia》1976,32(11):1376-1377
Allantoinase, an enzyme in the purine-urea cycle, was found in Eudistylia vancouveri (Polychaeta). The enzyme had a pH optimum at 7.6. The Km was 0.012 M allantoin, and the Arrhenius energy of activation was 12.6 to 14.6 kcal/mol.  相似文献   

14.
Summary Goldfinches (Carduelis carduelis) consume the feces of their nestlings until the digestive efficiency of nestlings and adults is nearly equal. With increasing nestling age from the first day onwards, the energy content of the nestlings' feces decreases. The percentage of fecal pellets swallowed by the adults during the course of the nestling period is negatively correlated with their energy content. It may be concluded that adults use the feces of their young as an energy source.  相似文献   

15.
In this paper we examine the reaction of the Leiden low-temperature laboratory of Heike Kamerlingh Onnes to new ideas in quantum theory. Especially the contributions of Albert Einstein (1906) and Peter Debye (1912) to the theory of specific heat, and the concept of zero-point energy formulated by Max Planck in 1911, gave a boost to solid state research to test these theories. In the case of specific heat measurements, Kamerlingh Onnes's laboratory faced stiff competition from Walter Nernst's Institute of Physical Chemistry in Berlin. In fact, Berlin got the better of it because Leiden lacked focus. After the liquefaction of helium in 1908, Kamerlingh Onnes transformed his laboratory into an international facility for low temperature research, and for this reason it was impossible to make headway with the specific heat measurements. In the case of zero-point energy, Leiden developed a magnetic research programme to test the concept. Initially the balance of evidence seemed to be tipping in favour of zero-point energy. After 1914, however, Leiden would desert the theory in fovour, of a concept from calssical physics. A curious move that illustrates Kamerlingh Onnes's discomfort with the new quantum theory.  相似文献   

16.
通过实体模型试验研究了某排水系统入海口水工建筑物的水力性能,设计提出一种新型的墩栅涡流室消能工。该新型消能工的水力特点是:流出排水隧洞的高速水流大部分通过进口墩栅空隙流入涡流室,小部分在进口墩栅前发生水跃后扎入涡流室中产生强烈的顺时针漩涡,通过水跃、墩栅的阻力和涡流室漩涡的共同作用消能,并将来流的动能转换为势能,之后,涡流室中的大部分水流在重力作用下通过出口墩栅空隙流向下游,其余水流从墩栅项部溢流。这种新型的墩栅涡流室不仅消能效果良好而且出流均匀,并容许各种杂物如石块、泥沙等自由通过,避免涡流室中发生严重的淤积。  相似文献   

17.
Summary The photic energy penetrating into the brain was increased in adult rats sustaining craniotomies sealed with transparent plastic. After blinding, these animals failed to entrain their circadian food intake rhythm to light-dark cycles. Short pulses of light did not phase-shift the freerunning rhythm. We conclude that adult rats lack brain photoreceptors mediating entrainment of circadian rhythms.  相似文献   

18.
国内外从盐湖卤水中提锂工艺技术研究进展   总被引:3,自引:0,他引:3  
金属锂及其化合物在能源和新材料方面具有重大应用前景,盐湖卤水提锂将成为21世纪锂盐生产的主攻方向。本文综合分析了国内外盐湖卤水提锂的工艺技术,提出了盐湖卤水提锂的发展趋势。  相似文献   

19.
20.
The steady state oxygen consumption of two echidnas was measured during locomotion on a treadmill. The change in power input with change in velocity is similar to that found in other mammals, but the total energy requirement for locomotion is less. The significance of these findings in an animal with low basal metabolism and distally heavy limbs is discussed.  相似文献   

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