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101.
应用磁异常信号监测填埋体位移的技术研究 总被引:1,自引:0,他引:1
在比较填埋场内部位移监测方法的基础上,提出利用增强填埋场内目标体所产生的磁异常信号(磁通量密度,以ΔT计)观测填埋体位移的方法. 建立正演模型,研究目标体磁异常信号的理论曲线变化特征及其在不同环境条件下的信号变化规律. 对ΔT实测值分析表明,填埋场环境背景值(-100~100 nT)并不会掩盖特征目标体磁异常信号的最大理论值(724.31~2 804.24 nT),确定了该方法的可行性. 模拟表明,在规定目标体大小、磁化强度的条件下,当目标体埋深为1~2 m时,其水平位置定位误差≤0.02 m,竖直位置定位误差≤0.09 m,证实了磁测定位方法具有良好的应用前景. 相似文献
102.
103.
Theory explains the structure of animal signals in the context of the receiver sensory systems, the environment through which
signals travel and their information content. The influence of signalling context on movement-based signalling strategies
is becoming clearer. Building upon recent findings that demonstrated changing environmental plant motion conditions resulted
in a change of signalling strategy by the Australian lizard Amphibolurus muricatus, we examined whether receiver distance also influences signalling strategies. We found that signalling lizards did not modify
their introductory tail flicking in response to distant viewers in the absence of competing, irrelevant plant image motion
despite significant reductions in signal structure at the eye of the viewer. The magnitude of resultant effect sizes strongly
suggests that receiver distance does not contribute to signalling strategies as much as the presence of motion noise in the
environment. 相似文献
104.
Pacific salmon are particularly susceptible to copper (Cu)-induced olfactory injuries that can ultimately inhibit neurobehaviors critical to survival. However, the molecular mechanisms underlying Cu-mediated olfactory impairment remain poorly understood. In the present study, we conducted a short-term Cu exposure at levels relevant to urban runoff (5, 25 and 50 ppb) , and investigated the roles of impaired olfactory signal transduction and induced apoptosis as underlying mechanisms of olfactory injury. Increased cell death in the olfactory epithelium was evident in coho receiving 4 h exposures to 25 and 50 ppb Cu. Expression of olfactory marker protein (omp), a marker of mature olfactory sensory neurons, also decreased at 50 ppb Cu. Immunohistochemical analysis of coho olfactory epithelium demonstrated a loss of type 3 adenylate cyclase (ACIII) in the apical olfactory epithelium cilia at all levels of Cu exposure, suggesting an inhibitory effect of Cu in olfactory signaling. Accompanying the loss of ACIII in Cu-exposed coho were reduced intracellular cyclic guanosine monophosphate (cGMP) levels in the olfactory rosettes. Collectively, these results support a linkage among the initial steps of olfactory signaling in Cu-induced salmon olfactory injury, and suggesting that monitoring olfactory cGMP levels may aid in the assessment of salmon olfactory injury. 相似文献
105.
In monogamous species, females often choose between males according to the quality of the territories they defend, but the
extent to which females themselves contribute to territory defence is frequently underestimated. Here we test for differences
in male and female roles during paired scent-marking bouts, a key component of territorial defence, in a monogamous antelope.
In two populations (Kenya, Zimbabwe) of klipspringer, Oreotragus oreotragus, both males and females usually scent-marked at the same site, but there were significant differences between sexes in terms
of investment within bouts. Females initiated most bouts, thus dictating the marking strategy of the pair. Males initiated
relatively few bouts, but deposited more scent marks per bout than females and were usually the last to scent-mark before
leaving the site; they marked on the same branches as the female and thus overmarked her scent. Both sexes deposited more
marks during paired than solo visits. Immediately preceding and following scent-marking bouts, males approached females and
females left males more often than expected. Female scent-marking rates were higher when they were receptive than at other
times, and this increase was matched by elevated marking rates of males. Females may increase marking rates when they are
receptive in order to test the quality of their mate or to incite male competition. However, these ideas are unlikely to explain
female scent-marking behaviour outside the mating season, which appears to be related primarily to territorial defence. We
suggest that these differences in investment in scent-marking bouts are consistent with predictions that females may be autonomously
territorial and that overmarking of female scent by males is a form of mate-guarding.
Received: 17 November 1999 / Received in revised form: 24 February 2000 / Accepted: 13 March 2000 相似文献
106.
The modulation of worker behavior by the vibration signal during house hunting in swarms of the honeybee, Apis mellifera 总被引:3,自引:3,他引:0
During house hunting, honeybee, Apis melli- fera, workers perform the vibration signal, which may function in a modulatory manner to influence several aspects of nestsite
selection and colony movement. We examined the role of the vibration signal in the house-hunting process of seven honeybee
swarms. The signal was performed by a small proportion of the older bees, and 20% of the vibrating bees also performed waggle
dances for nestsites. Compared to non-vibrating controls, vibrating bees exhibited increased rates of locomotion, were more
likely to move into the interiors of the swarms, and were more likely to fly from the clusters and perform waggle dances.
Recipients responded to the signal with increased locomotion and were more likely than non- vibrated controls to fly from
the swarms. Because vibration signals were intermixed with waggle dances by some vibrators, and because they stimulated flight
in recipients, the signals may have enhanced nestsite scouting and recruitment early in the house-hunting process. All swarms
exhibited increased vibration activity within 0.5–1 h of departure. During these final periods, numerous vibrating bees wove
repeatedly in and out of the clusters while signaling and motion on the swarms increased until it culminated in mass flight.
The peaks of vibration activity observed at the end of the house-hunting process may therefore have activated the entire swarm
for liftoff once a new nestsite had been selected. Thus, the vibration signal may help to integrate the behavior of numerous
groups of workers during nestsite selection and colony relocation.
Received: 17 January 2000 / Received in revised form: 5 April 2000 / Accepted: 3 May 2000 相似文献
107.
A. Kunwar 《International Journal of Green Energy》2016,13(4):335-343
High penetration level of wind power has significant impact on the dynamic performance of power system. Power system with existing high-voltage direct current (HVDC) link may influence the stability of power system at high penetration level of wind power. This article investigates the stability issues of power system with existing HVDC link for different penetration level of doubly fed induction generator (DFIG) and direct drive synchronous generator (DDSG) based wind farms. The small signal stability analysis shows that power system with HVDC link has improved the stability of the power system for increased penetration of DFIG- and DDSG-based wind farms. 相似文献
108.
109.
SO2是一种常见的大气污染物,急性和慢性暴露都会对植物造成伤害.因此,本文以景观绿化植物萱草叶片下表皮为材料,研究了SO2对气孔保卫细胞的致死效应及其可能的信号调节途径.结果表明,利用SO2体内衍生物-亚硫酸钠和亚硫酸氢钠混合液处理萱草表皮3 h后,随着处理浓度(1.0~5.0 mmol·L-1)的增加,萱草保卫细胞生理活性下降,甚至死亡;浓度超过2.0 mmol·L-1时,细胞死亡率显著增高(p0.05),死细胞出现核固缩、核拉长、核碎片等典型凋亡特征,保卫细胞内的活性氧种(ROS)、一氧化氮(NO)和Ca2+水平显著升高.采用不同浓度的抗氧化剂过氧化氢酶(CAT)、抗坏血酸(AsA),Ca2+螯合剂乙二醇双四乙酸(EGTA)和Ca2+通道抑制剂氯化镧(LaCl3)及NO清除剂羧基-2苯-4,4,5,5-四甲基咪唑-1-氧-3氧化物(C-PTIO)和合成抑制剂叠氮钠(NaN3)处理后,均可使SO2衍生物诱发的细胞死亡率降低,以200 U·mL-1CAT、0.05 mmol·L-1的AsA、EGTA、LaCl3及0.20 mmol·L-1的C-PTIO、NaN3的效果最佳,同时胞内ROS、NO和Ca2+水平下降.以上结果表明,一定浓度的SO2可诱导萱草保卫细胞死亡,可能通过诱导ROS和NO爆发,激活细胞质膜钙通道,进而引起胞内Ca2+增加,通过ROS-NO-Ca2+信号途径介导细胞死亡.SO2诱导的萱草细胞死亡可能存在细胞凋亡过程. 相似文献
110.
泥石流冲击荷载的时频分析方法及应用 总被引:1,自引:0,他引:1
泥石流的能量转化主要集中于运动过程中,泥石流冲击压力随时间变化的过程是其能量不断变化的综合表现.本文分析了泥石流能量转化过程及冲击荷载的紊流形态,并根据其脉动特性,将泥石流冲击荷载作为信号进行研究.以大型泥石流模型试验为基础,利用小波时频分析方法将试验测取的泥石流冲击荷载映射为时间与频率的联合信号,得到同一时间9个频段... 相似文献