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101.
The behavioral and electrophysiological activity of a mimic [(Z,E)7,9,11-dodecatrienyl formate] of the major sex pheromone component [(Z,E) 9,11,13-tetradecatrienal] of carob moth was assessed. Wind-tunnel bioassays demonstrated that the formate was as effective as natural gland extracts, and significantly more effective than the trienal alone or than the trienal blended with two minor pheromone components, in evoking source contact. Dispensers containing the formate were as effective as trienal-containing blend lures in attracting males when placed at the same dosage in traps in date gardens. Single-cell recordings showed that at least two olfactory neurons, differentiated by spike amplitude, are located in the long trichoid hairs on male carob moth antennae. Dose-response relationships indicated that puffs from cartridges loaded with at least 0.1 g of the formate or of the trienal were necessary to elicit spiking by either the small or the large-spiking cell within a sensillum. Cross-adaptation studies demonstrated that both compounds stimulated the same large-spiking cell. The frequencies of spikes evoked from the large cell when stimulated by emissions from 0.1-g, 1-g, or 10-g cartridges of either the formate or the trienal were not significantly different, suggesting that the formate is an effective mimic of the trienal at the antennal receptor cell level.  相似文献   
102.
Surface roughness is one of the most important requirements in machining process. The surface roughness value is a result of the tool wear. When tool wear increase, the surface roughness also increases. The determination of the sufficient cutting parameters is a very important process obtained by means of both minimum surface roughness values and long tool life. The statistical models were developed to predict the surface roughness.This paper presents the development of a statistical model for surface roughness estimation in a high-speed flat end milling process under wet cutting conditions, using machining variables such as spindle speed, feed rate, depth of cut, and step over. First- and second-order models were developed using experimental results of a rotatable central composite design, and assessed by means of various statistical tests. The highest coefficient of correlation (Radj2) (88%) was obtained with a 10-parameter second-order model. Meanwhile, a time trend was observed in residual values between model predictions and experimental data, reflecting the probable effect of the tool wear on surface roughness. Thus, in order to enhance the estimation capability of the model, another independent variable was included into the model to account for the effect of the tool wear, and the total operating time of the tool was selected as the most suitable variable for this purpose. By inserting this new variable as a linear term into the model, Radj2 was increased to 94% and a good fit was observed between the model predictions and supplementary experimental data.In this study, it was observed that, the order of significance of the main variables is as X5>X3>X4>X1>X2 (total machining time, depth of cut, step over, spindle speed and feed rate, respectively).  相似文献   
103.
Simulation of smoke flow and longitudinal ventilation in tunnel fire   总被引:5,自引:0,他引:5  
1 Introduction The tunnel is one of the important facilities of railroad and highway transportation, and also a throat of railroad and highway. With the development of transportation, there are more and more tunnels. Although the tunnel fire occurs seldo…  相似文献   
104.
105.
依托吉林引松工程开展隧道掘进机(TBM)施工参数预测研究,提出TBM施工数据分段提取算法,提取上升段前30 s的总推进力、刀盘转速、推进速度、刀盘扭矩、刀盘转速电位器设定值、推进速度电位器设定值、贯入度、贯入度指数(FPI)、扭矩切深指数(TPI)9个参数作为输入;通过局部线性嵌入(LLE)完成对上升段数据特征的降维;基于支持向量机回归(SVR)建立TBM施工控制参数(推进速度、刀盘转速)和负载参数(总推进力、刀盘扭矩)预测模型. 分析是否结合前一掘进循环的FPI、TPI指数进行预测对预测效果的影响. 结果表明,上述方法在推进速度、刀盘转速、总推进力、刀盘扭矩的预测中均取得了较好的预测效果,平均预测绝对百分比误差均小于15%,验证了该预测方法的有效性,该方法可以为TBM现场施工提供指导.  相似文献   
106.
为了构建公路隧道衬砌碳化耐久性的定量设计方法,对比各碳化深度计算模型与实测数据,选定衬砌碳化的最优模型;根据实测数据分析隧道环境温湿度与洞外大气关系,基于全国气象监测站的温湿度数据,建立公路隧道运营环境温湿度区划;考虑公路隧道CO2的释放源项并参照实测数据,构建隧道运营环境CO2体积分数的计算方法;以碳化劣化速率梯度相等为原则,对我国隧道碳化环境进行分区,结合分区推荐我国公路隧道衬砌碳化耐久性定量设计的具体方法. 研究发现:隧道环境湿度与大气湿度相当,隧道环境温度变化趋势与大气环境一致,两者均值接近. 公路隧道内部CO2体积分数与CO体积分数呈线性关系. 云南、贵州区修建的隧道工程衬砌受环境影响较大,西藏、青海、内蒙古、黑龙江、吉林等地区的待建隧道在进行衬砌耐久性设计时可以忽略碳化影响,其余全国大面积区域隧道衬砌的碳化耐久性设计可以对应《混凝土结构耐久性设计标准》中环境作用等级中的“轻度”进行设计.  相似文献   
107.
依托作为河北省交通厅重点研究项目"高速公路复杂地层双连拱隧道施工控制工艺研究与应用"项目,以张石高速公路某连拱隧道为研究对象,通过对中导洞双侧洞法施工过程中现场测量的数据进行分析整理,得出了有关浅埋软弱岩体隧道一般施工监测的分析结果.  相似文献   
108.
高水头泄水建筑物侧墙掺气减蚀特性研究   总被引:9,自引:1,他引:8  
工程中通常采用强迫掺气减蚀措施,防止泄水建筑物在高速水流作用下发生空蚀破坏,但在保护过流面底板的同时,忽视了对其侧墙的保护。为了减免位于高流速区域和低压区域侧墙发生空化空蚀,消除侧墙清水区,采用理论分析和物理模型试验研究方法,对龙抬头明流泄洪洞下游边墙掺气减蚀进行了研究,提出了在反弧末端加折流器(突扩)和突跌掺气方式。结果表明,采用突扩和突跌的掺气方式后,侧墙水流的出射角增大,侧空腔畅通,并直接和底空腔相连,有助于掺气坎后水舌的全断面的掺气,对侧墙和底板皆起到了很好的保护作用。  相似文献   
109.
Entrapment neuropathy (EN) is a prevalent and debilitative condition caused by a complex pathogenesis that involves a chronic compression–edema–ischemia cascade and perineural adhesion that results in excessive shear stress during motion. Despite decades of research, an easily accessible and surgery-free animal model mimicking the mixed etiology is currently lacking, thus limiting our understanding of the disease and the development of effective therapies. In this proof-of-concept study, we used ultrasound-guided perineural injection of a methoxy poly(ethylene glycol)-b-Poly(lactide-co-glycoilide) carboxylic acid (mPEG-PLGA-BOX) hydrogel near the rat’s sciatic nerve to induce EN, as confirmed sonographically, electrophysiologically, and histologically. The nerve that was injected with hydrogel appeared unevenly contoured and swollen proximally with slowed nerve conduction velocities across the injected segments, thus showing the compressive features of EN. Histology showed perineural cellular infiltration, deposition of irregular collagen fibers, and a possible early demyelination process, thus indicating the existence of adhesions. The novel method provides a surgery-free and cost-effective way to establish a small-animal model of EN that has mixed compression and adhesion features, thus facilitating the additional elucidation of the pathophysiology of EN and the search for promising treatments.  相似文献   
110.
The γ-aminobutyric acid type A receptor (GABAAR) plays a major role in fast inhibitory synaptic transmission and is highly regulated by the neuromodulator dopamine. In this aspect, most of the attention has been focused on the classical intracellular signaling cascades following dopamine G-protein-coupled receptor activation. Interestingly, the GABAAR and dopamine D5 receptor (D5R) have been shown to physically interact in the hippocampus, but whether a functional cross-talk occurs is still debated. In the present study, we use a combination of imaging and single nanoparticle tracking in live hippocampal neurons to provide evidence that GABAARs and D5Rs form dynamic surface clusters. Disrupting the GABAAR–D5R interaction with a competing peptide leads to an increase in the diffusion coefficient and the explored area of both receptors, and a drop in immobile synaptic GABAARs. By means of patch-clamp recordings, we show that this fast lateral redistribution of surface GABAARs correlates with a robust depression in the evoked GABAergic currents. Strikingly, it also shifts in time the expression of long-term potentiation at glutamatergic synapses. Together, our data both set the plasma membrane as the primary stage of a functional interplay between GABAAR and D5R, and uncover a non-canonical role in regulating synaptic transmission.  相似文献   
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