共查询到16条相似文献,搜索用时 46 毫秒
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为了探讨航天飞行初期人体生理功能的变化及“空间适应性综合症”的机理,实验观察了12名受试者在头低位6°卧床期间心率、呼吸、体温和脑电的变化。实验中所有指标均同时记录在卧床实验室配套的生理测试处理系统上,并用此系统对各生理指标的变化进行计算机分析。分析结果表明头低位卧床中人体内的一些重要生理功能如心率、呼吸、脑电的昼夜节律仍存在,但出现一定的紊乱,表现在:①心率昼夜变化双峰波消失或模糊,时相推迟。②体温昼夜节律变化不明显;额部皮肤温度无明显的昼夜节律变化,腿部皮肤温度在卧床初期明显增加,之后波动较大。③卧床中脑电α波段功率谱值下降,而δ、θ波功率谱值上升。卧床中R-R 间期频谱分析和脑电功率谱分析的结果表明卧床中心脑的调节和皮层的兴奋性也发生一定变化。 相似文献
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空间失重引起的骨代谢调节失衡是航天员遭受的最严重的危害之一.骨代谢失衡还有可能影响机体的糖脂代谢平衡.本研究利用恒河猴头低位卧床模拟失重效应实验方法,分析头低位卧床过程中恒河猴血清中骨代谢、糖脂代谢指标变化情况及其相关性.卧床组恒河猴血清中BAP在头低位卧床实验开始7天便出现了显著下降(P<0.05),血清胰岛素、高密度脂肪酸含量在7天显著下降并一直维持在较低水平,血糖含量在7天时显著下降,但在21天时明显回升.分析发现,骨钙素与血糖、皮质醇、高密度脂肪酸含量间均存在相关性,这表明头低位卧床模拟失重效应实验中骨与糖脂代谢之间存在相互调控. 相似文献
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载人航天或模拟失重后,航天员会出现运动能力与立位耐力降低,其发生机理与多种因素的改变有关.为进一步验证这种变化与中枢神经系统调节功能障碍的可能相关,本文研究模拟失重过程中心脏与外周血管自主神经调节功能的动态变化及与卧床后立位耐力降低的关系.结果表明,6名被试者的HRV谱的总功率(TP)及低频(LF)、高频(HF)成份均减少,而LF:HF比值在卧床后期有增大趋势.卧床后HUT初始6min所有被试者心率明显快于卧床前的相应值.说明模拟失重后心脏迷走神经反应与外周血管交感神经活动水平降低,心脏交感神经活动水平逐渐升高.但卧床后HUT时心血管自主神经调节反应基本正常. 相似文献
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模拟失重兔脑波超慢涨落图的研究 总被引:4,自引:0,他引:4
兔在头低位悬吊的15天中,脑电的超慢涨落发生明显的改变,表现为16谱段、S_1~S_8谱结构、S 谱谐振及功率比的变化,这些变化反映了悬吊对脑功能的影响。结果表明脑电超慢涨落技术可应用到航天脑功能的研究中去。 相似文献
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航天员在轨道飞行时,由于失重因素,产生了一系列生理、病理变化,出现了空间运动病、心血管和水盐代谢紊乱、骨质脱钙、肌肉萎缩等机能紊乱和失调。这些变化或多或少地影响了航天员的健康和工作,及返回地球的再适应能力,并可能成为长时间航天飞行的主要障碍。因此,了解失重对人体的影响、生理机能失调的机制及采取有效的防护措施是十分必要的。但是在航天飞行中航天员的人数有限,且任务繁忙不能进行大量的生理实验和测试。加之,飞行中的实验 相似文献
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因失重时血循环系统的改变十分类似于中医“血淤症”时的变化,故采用活血化淤中药来改善失重时的血循环状态可能是一种较好的防护措施。实验比较了4种中药(丹-黄合剂、川芎、冠心Ⅱ号、樟柳碱)对模拟失重兔耳微循环和血液流变性的影响。结果表明4种中药均有改善模拟失重兔血循环的作用,其效果是丹-黄合剂>川芎>冠心Ⅱ号>樟柳碱。两种药量实验结果表明丹黄合剂用15g/kg,川芎用10g/kg 效果较好。 相似文献
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航天“血淤症”及其防护措施 总被引:3,自引:0,他引:3
沈羡云 《中国空间科学技术》1991,11(6):57-61,56
根据实验结果及国外有关资料证明,失重或模拟失重时人和动物血循环系统的紊乱和中医“血淤症”时的变化十分相似,提出我国“活血化淤”中药有可能成为防止失重血循环紊乱的一种有效药物的看法。 相似文献
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失重因素对航天员体温调节影响的分析 总被引:1,自引:0,他引:1
系统地总结了实际载人航天及地面模拟中失重因素引起的航天员生理性体温调节功能变化的种种现象和内在联系。指出在失重环境下 ,自然对流消失 ,血液重新分布 ,排尿性失水增加 ,血浆容积变小 ,心血管系统功能下降 ,最大氧摄入量降低 ,这些都可导致体温调节能力受损 ,最终使航天员的高温耐力明显下降。文章同时指出 ,在体温调节系统中 ,行为性调节是生理性调节的补充和延伸 ,前者只有通过后者才能发挥作用 ,因此 ,在航天器座舱温控系统及航天服通风 -液冷系统的设计中 ,应充分考虑失重因素的影响。 相似文献
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以空间装置中气体自然对流传热问题为目标,导出显含温度和压强两个独立热力学参数的Rayleigh 数和Knudsen 数的表达式,分析了各个特征压强段气体传热的不同状态,比较了在连续介质流动中低真空(压强大于10Pa)和微重力对空间装置中气体自然对流传热的相似影响,导出了气体压强与重力对低真空气体自然对流的影响的相似性关系式,由此可以推断低真空或微重力状态下气体自然对流的强弱的相互关系。 相似文献
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Sonja Brungs Jens Hauslage Reinhard Hilbig Ruth Hemmersbach Ralf Anken 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Stimulus dependence is a general feature of developing sensory systems. It has been shown earlier that the growth of inner ear heavy stones (otoliths) of late-stage Cichlid fish (Oreochromis mossambicus) and Zebrafish (Danio rerio) is slowed down by hypergravity, whereas microgravity during space flight yields an opposite effect, i.e. larger than 1 g otoliths, in Swordtail (Xiphophorus helleri) and in Cichlid fish late-stage embryos. These and related studies proposed that otolith growth is actively adjusted via a feedback mechanism to produce a test mass of the appropriate physical capacity. Using ground-based techniques to apply simulated weightlessness, long-term clinorotation (CR; exposure on a fast-rotating Clinostat with one axis of rotation) led to larger than 1 g otoliths in late-stage Cichlid fish. Larger than normal otoliths were also found in early-staged Zebrafish embryos after short-term Wall Vessel Rotation (WVR; also regarded as a method to simulate weightlessness). These results are basically in line with the results obtained on Swordtails from space flight. 相似文献
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C.H. Jaroschek M. Hoshino H. Lesch R.A. Treumann 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(3):481-490
We address the problem of interacting relativistic current sheets in self-consistent kinetic plasma simulations within the framework of the Particle-In-Cell model. The interaction is enforced in head-on collisions of up to 10 current sheets at relativistic bulk speeds. The simulations are motivated by the general problem of Poynting flux dissipation in ‘striped wind’ configurations presumably governing the relativistic outflows pervasive in pulsar winds and gamma-ray bursts. We identify the generation of non-thermal particles and formation of a stable power-law shape in the particle energy distributions f(γ) dγ ∝ γ−s dγ. In 1D, a spectral index s ∼ 2 is observed and attributed to a stochastic Fermi-type acceleration mechanism. In 2D, the generic index of s ∼ 3–4 is retained as in previous simulations of individual current sheets. Whereas in 2D the high energy cut-off is constrained by the limited dissipation of magnetic energy, in 1D the process converts the bulk motion of current sheets towards directed particle momentum of an exclusive class of non-thermal particles. 相似文献
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Samujjwal Ray Rajdeep Ray Mofazzal Hossain Khondekar Koushik Ghosh 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(8):2214-2226
A monthly average solar green coronal index time series for the period from January 1939 to December 2008 collected from NOAA (The National Oceanic and Atmospheric Administration) has been analysed in this paper in perspective of scaling analysis and modelling. Smoothed and de-noising have been done using suitable mother wavelet as a pre-requisite. The Finite Variance Scaling Method (FVSM), Higuchi method, rescaled range (R/S) and a generalized method have been applied to calculate the scaling exponents and fractal dimensions of the time series. Autocorrelation function (ACF) is used to find autoregressive (AR) process and Partial autocorrelation function (PACF) has been used to get the order of AR model. Finally a best fit model has been proposed using Yule-Walker Method with supporting results of goodness of fit and wavelet spectrum. The results reveal an anti-persistent, Short Range Dependent (SRD), self-similar property with signatures of non-causality, non-stationarity and nonlinearity in the data series. The model shows the best fit to the data under observation. 相似文献