烘烤湿球温度对皖南烟叶焦甜香风格的影响

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。     

Somatostatin and Astroglial Involvement in the Human Limbic System in Alzheimer’s Disease

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.     

Olfactory bulb habituation to odor stimuli.

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)     

Flexural behaviour of a half-decked bulb tee pre-stressed concrete girder: full-scale test and nonlinear finite element analysis

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.     

440 MPa级高强度球扁钢的热处理工艺

采用金相显微镜、透射电镜、相分析等实验分析方法,研究了不同热处理工艺对10CrNiMoV球扁钢组织和力学性能的影响。结果表明,热轧或正火连续冷却过程中,形成了大量的粒状贝氏体,显著降低了钢的韧性。正火加高温回火处理后,粒状贝氏体得到了一定程度的分解,虽其屈服强度有所下降,但显著提高了10CrNiMoV球扁钢的低温韧性,?40 ℃冲击功达到117 J。通过正火＋控冷＋高温回火处理后,形成了一定量的多边形铁素体,并且粒状贝氏体得到了充分的分解,获得了良好的综合性能。     

大型贯流式机组调速系统的研究

灯泡贯流式水轮发电机作为一种专门应用于大流量、低水头的水轮机,由于其自身转动惯量小,机组结构和安装方式都与常规的混流式、冲击式水轮发电机之间存在着显著的差异。其配套的调速系统在电气控制策及液压控制回路上的部件配置与常规的水轮机相比都有所不同。文中针对南瑞集团公司电气控制所（以下简称南瑞电控所）所研制的贯流式水轮发电机调速系统,对其控制原理、配置设定和实际运用情况进行了阐述和说明。     

振动测量值对灯泡贯流式机组运行的指导

通过居龙滩水电厂灯泡贯流式机组运行时某些部位（如水导轴承）振动幅值超标的现象,从导叶和桨叶协联关系、机组的结构特点、运行工况等方面分析了振动幅值超标的原因,并提出如何利用机组的振动测量值指导机组的运行,从而保证机组的安全运行。     

红外辐射多孔陶瓷的研制

为了研制1种新型轻质热工材料——红外辐射多孔陶瓷,研究了其配方组成及制备工艺,对材料的微观结构、气孔的尺寸和分布、气孔率、体积密度、导热系数、机械性能及热发射率分别进行了测定。结果表明:采用发泡和添加造孔剂相结合的制备工艺,可获得孔径小且分布均匀,具有优良绝热性能及较高常温耐压强度的红外辐射多孔陶瓷材料,且掺入由过渡族氧化物组成的高辐射率材料,可使该材料在整个红外辐射波段都具有很高的发射率。     

10CrNi3MoV对称球扁钢性能均一性分析

通过对连铸球扁钢横截面硬度测试、拉伸及冲击性能测试、金相组织与晶粒度的观察评定,研究了10CrNi3MoV对称球扁钢的性能均一性。结果表明,应进一步提高10CrNi3MoV性能均一性,缩小球头和腹板性能差异,改善沿轧制方向不同部位力学性能的明显差别。     

嗅球中神经元间的相互作用及同步运动分析

嗅球对嗅觉信息的处理是嗅觉系统信号编码的一个重要环节,其中兴奋性的僧帽细胞（Mitral Cell, MC）与抑制性的颗粒细胞（Granular Cell, GC）的相互作用尤为关键。本文首先介绍了嗅觉系统网络中关于同步振荡的研究现状,然后建立嗅球中僧帽细胞及颗粒细胞的动力学模型,仿真得到了单个僧帽细胞、颗粒细胞以及僧帽细胞与颗粒细胞在耦合条件下神经元的发放模式。结果表明,僧帽细胞对颗粒细胞有兴奋性作用,而颗粒细胞对僧帽细胞有抑制性作用,细胞放电序列随着突触连接强度的改变而改变。此外,建立简单的嗅觉网络模型,分析了当颗粒细胞分别构成环形和网格状两种拓扑结构时,不同网络对两个僧帽细胞同步性的影响,用同步性指标ISI-distance刻画同步程度。数值分析表明颗粒细胞网格状的拓扑结构对僧帽细胞的同步性作用更为明显一些。