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111.
以泰国NARESUANA电站灯泡贯流式水轮发电机组及其调速器为例证,着重说明了灯泡贯流机组的特点,阐述了调速器的步进电机系统研制和应用:1采用适应式、变结构、变参数、并联PID调节模式,使机组在不同状态下均能稳定运行;2采用变参数导叶分段关闭装置,根据水头、负荷、频率等机组工况自动改变导叶分段关闭投入点,减少了快速关闭时造成水击压力的升高,并防止涌浪、低频及水锤的发生;3桨叶根据机组频率自动改变关闭速度,防止涌浪、低频及水锤的发生。 相似文献
112.
113.
高速重载双圆弧齿轮传动优化设计 总被引:2,自引:0,他引:2
这里使用数学规划理论与计算机程序设计方法相结合,通过例证对目前广泛应用于现代机器的高速重载双圆弧齿轮传动计算机辅助优化设计进行了初步探讨。试图用尽可能快的速度、简单、易懂、可行的方法设计出技术经济效果最佳的双圆弧齿轮传动。 相似文献
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115.
马铃薯饼加工工艺及配方 总被引:3,自引:0,他引:3
介绍了以马铃薯为主要原料加工而成的几种不同口味的食品,并且详细地介绍了全部工艺过程及有关技术与设备。 相似文献
116.
New types of ecologically friendly polymer flame-retardant systems were proposed for Nylon 6,6 and polypropylene [high temperature polymer–organic char former, poly(vinyl alcohol), and silicon–inorganic system]. These systems can act in condensed and gaseous phases. The cone calorimeter and LOI tests indicated the improvement of fire-retardant properties for compositions of flame retardants with Nylon 6,6 and polypropylene in comparison with pure polymers. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:715–725, 1998 相似文献
117.
烘烤湿球温度对皖南烟叶焦甜香风格的影响 总被引:1,自引:0,他引:1
为了探明不同烘烤阶段湿球温度对皖南焦甜香烟叶香气成分及焦甜香风格的影响,以云烟97为参试材料,研究了烤烟烘烤变黄后期、定色前期、定色后期和干筋期的湿球温度和优化组合与皖南焦甜香烟叶香气成分及焦甜香风格的关系。结果表明,在变黄后期、定色期和干筋期,随着湿球温度的提高,烤后烟叶内、外观质量均有先改善后变差的趋势,主要香味成分含量和焦甜香关联香味成分含量呈现出先增加后降低的趋势,且变黄后期和定色前期的影响明显大于定色后期和干筋期。烘烤过程中,以中湿烘烤,即变黄后期和定色前期湿球温度37℃,定色后期湿球温度38℃,干筋期湿球温度40℃,有利于彰显烟叶焦甜香风格。 相似文献
118.
Melania Gonzalez-Rodriguez Veronica Astillero-Lopez Patricia Villanueva-Anguita M. Eugenia Paya-Rodriguez Alicia Flores-Cuadrado Sandra Villar-Conde Isabel Ubeda-Banon Alino Martinez-Marcos Daniel Saiz-Sanchez 《International journal of molecular sciences》2021,22(16)
Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease in the elderly. Progressive accumulation of insoluble isoforms of amyloid-β peptide (Aβ) and tau protein are the major neuropathologic hallmarks, and the loss of cholinergic pathways underlies cognitive deficits in patients. Recently, glial involvement has gained interest regarding its effect on preservation and impairment of brain integrity. The limbic system, including temporal lobe regions and the olfactory bulb, is particularly affected in the early stages. In the early 1980s, the reduced expression of the somatostatin neuropeptide was described in AD. However, over the last three decades, research on somatostatin in Alzheimer’s disease has been scarce in humans. Therefore, the aim of this study was to stereologically quantify the expression of somatostatin in the human hippocampus and olfactory bulb and analyze its spatial distribution with respect to that of Aβ and au neuropathologic proteins and astroglia. The results indicate that somatostatin-expressing cells are reduced by 50% in the hippocampus but are preserved in the olfactory bulb. Interestingly, the coexpression of somatostatin with the Aβ peptide is very common but not with the tau protein. Finally, the coexpression of somatostatin with astrocytes is rare, although their spatial distribution is very similar. Altogether, we can conclude that somatostatin expression is highly reduced in the human hippocampus, but not the olfactory bulb, and may play a role in Alzheimer’s disease pathogenesis. 相似文献
119.
Chaudhury Dipesh; Manella Laura; Arellanos Adolfo; Escanilla Olga; Cleland Thomas A.; Linster Christiane 《Canadian Metallurgical Quarterly》2010,124(4):490
Habituation is a simple form of memory, yet its neurobiological mechanisms are only beginning to be understood in mammals. In the olfactory system, the neural correlates of habituation at a fast experimental timescale involving very short intertrial intervals (tens of seconds) have been shown to depend on synaptic adaptation in olfactory cortex. In contrast, behavioral habituation to odorants on a longer timescale with intertrial intervals of several minutes depends on processes in the olfactory bulb, as demonstrated by pharmacological studies. We here show that behavioral habituation to odorants on this longer timescale has a neuronal activity correlate in the olfactory bulb. Spiking responses of mitral cells in the rat olfactory bulb adapt to, and recover from, repeated odorant stimulation with 5-min intertrial intervals with a time course similar to that of behavioral habituation. Moreover, both the behavioral and neuronal effects of odor habituation require functioning N-methyl-d-aspartic acid receptors in the olfactory bulb. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
120.
A half-deck bulb tee (HBT) girder, which is an unusual concept for pre-stressed concrete girders, was developed and tested for a long span application. The purpose of the test was to simplify the construction process and increase structural performance by optimising the cross sections and improving the efficiency of the tendon profile. In this study, a full-scale HBT girder, with a length of 60 m and depth of 2.3 m, which includes the .1 m depth of the half-deck, was fabricated and tested to analyse its structural performance. The data observed from the flexural loading tests were evaluated by comparing with the results of finite element analysis (FEA). The tested HBT girder specimen was expected to be sufficiently safe for actual bridge design because it satisfied construction code requirements. The initial cracking load observed during the experiment (1400 kN) was accurately predicted by FEA (1420 kN) and theory (1301 kN). Therefore, the developed HBT girder has sufficient and predictable flexural strength. 相似文献