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1.
用立位加下身负压作为负荷,被试者心血管反应可分成四种不同特征,即血管型、混合型、心脏型和欠调型。它们主要特征分别表现为:血管型以增加外周阻力为主;混合型心率和外周阻力都明显增加;心脏型心率增加非常明显;欠调型心率和外周阻力都调节不上去。负荷耐力以血管型最佳,混合型第二,心脏璎第三,欠调型较差。在卧床期间,被试者主观感觉和客观检查也表现为血管型和混合型较其它两种反应类型为好。卧床前后负荷试验的反应特征基本相似。用模糊数学的概念处理这些数据,可以定量地比较出心血管反应特征的差异。   相似文献   

2.
4小时头低位卧床期间脑阻抗图的变化   总被引:5,自引:0,他引:5  
为了检查被试者对失重的适应能力,本实验采用了4h 头低位15°卧床方法模拟失重,观察了38名被试者在卧床中的耐受时间和脑阻抗图(REG)的变化,结果是短时间的头低位卧床期间REG 发生了规律性的变化,此变化反映了被试者脑循环系统状态,并与被试者卧床耐力一致。结果提示,短期头低位卧床可作为检查被试者失重适应能力的一种方法,而REG 是一个有用的评定指标。  相似文献   

3.
立位加下身负压时的心血管反应   总被引:1,自引:1,他引:1  
本实验采用了立位加下身负压方法(负-立方法)模拟航天员返回地面后受到的重力刺激,检查了20名健康受试者在单纯立位和负-立时的心血管反应。按照受试者在负-立时的心率、外周阻力和耐受时间,将受试者分为四种不同的反应类型,其耐力和潜力是血管型>混合型>心脏型>欠调型。结果表明负-立方法是一种很好的心血管功能检查方法,可应用于航天员心血管功能选拔。  相似文献   

4.
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   

5.
通过对大鼠尾吊模型进行改进,研制出一种新型可调节体位的大鼠后肢去负荷悬吊装置,研究模拟微重力效应下体液分布变化对大鼠骨代谢的影响.将36只SD大鼠均分为对照组(CON)、头低位后肢去负荷组(HDT)、水平位后肢去负荷组(HH)和头高位后肢去负荷组(HUT)4组,实验21天后,利用DXA检测大鼠的骨密度(BMD).模拟微重力效应下的三组大鼠后肢均发生严重骨丢失,其中HH和HUT组后肢BMD显著大于HDT组.实验结果表明,体液分布变化可能在模拟微重力效应导致的骨丢失中起到重要作用,新型大鼠后肢去负荷悬吊装置能够调节大鼠体位(体液)进行模拟微重力效应研究.   相似文献   

6.
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   

7.
为研究心率变异性(HRV)指标在管制员(ATC)疲劳检测中的适用性,搭建模拟管制实验平台,利用生理记录仪实时记录20名被试正常和疲劳状态下的心电(ECG)信号,并采集其主观疲劳度(卡罗林斯卡嗜睡量表)和操作绩效。利用偏相关分析选取与被试疲劳等级相关性高的心率变异性指标,并用于管制员疲劳检测的多元线性回归建模。分析结果表明:SDNN与被试的疲劳状态无相关性;LFnorm和HFnorm与疲劳程度呈弱相关;RR间期均值、LF/HF均与被试的疲劳度存在较强的相关性,二者结合建立的多元线性回归模型,拟合优度大于0.5,RR间期均值和LF/HF可作为检测管制员疲劳的有效指标。本文研究成果可为未来的管制员疲劳实时检测提供科学依据和实验支撑。   相似文献   

8.
本文研究了-6°卧床模拟失重对T淋巴细胞受到有丝分裂原刺激后增殖能力和外周血总T淋巴细胞亚群(CD3+T细胞)、辅助/炎性T细胞亚群(CD4+T细胞)、杀伤T细胞亚群(CD8+T细胞)、及表达CD25分子细胞数的影响,同时观察生长激素、促肾上腺皮质激素、皮质激素的改变,来探讨免疫功能的变化与内分泌系统改变的关系.结果表明,模拟失重造成的免疫功能下降与内分泌系统紊乱有关.   相似文献   

9.
飞机座舱显示界面脑力负荷测量与评价   总被引:3,自引:2,他引:1  
脑力负荷是影响飞行安全的重要因素之一,对飞行员脑力负荷进行客观测量,对于飞机座舱显示界面脑力任务的工效评价与优化设计具有重要意义.基于ERP(Eveat Related Potential)技术,选取失匹配负波(MMN,Mismatch Negativity)和P3a成分为指标,采用三刺激“oddball”模式,在飞行模拟任务条件下开展了三级脑力负荷的测量与评价研究.实验结果表明,MMN峰值和P3a峰值对脑力负荷变化敏感,随着脑力负荷的增加,MMN峰值显著增加,而P3a峰值显著降低,反应了被试者对异常信息的自动加工能力的提高以及朝向注意能力的减弱.与新异刺激相比,由偏差刺激所诱发的MMN与P3a成分对于与飞行任务相关的脑力负荷具有更好的敏感性,将可用于进一步的脑力负荷分级评价.   相似文献   

10.
太空行走的训练设备(下) 88.约翰逊航天中心的失重环境训练设备有何特点?有哪些辅助设施?失重环境训练设备(WETF)是建在约翰逊航天中心的第29号大楼内。这个大楼原来是放置载人离心机的地方,因为航天飞机在发射时的加速度最高只有3g,航天员完全可以耐受,这样就不需要载人离心机的训练,因此在上世纪70年代中期航宇局将载人离心机拆除,改建成一个大型中性浮力水池。  相似文献   

11.
The Houston Museum of Natural Science, in collaboration with Rice University has an outreach program taking portable digital theaters to schools and community sites for over five years and has conducted research on student learning in this immersive environment. By using an external independent evaluator, the effectiveness of NASA-funded Education and Public Outreach (EPO) projects can be assessed. This paper documents interactive techniques and learning strategies in full-dome digital theaters. The presentation is divided into Evaluation Strategies and Results and Interactivity Strategies and Results. All learners from grades 3–12 showed statistically significant short-term increase in knowledge of basic Earth science concepts after a single 22-min show. Improvements were more significant on items that were taught using more than one modality of instruction: hearing, seeing, discussion, and immersion. Thus immersive theater can be an effective as well as engaging teaching method for Earth and Space science concepts, particularly those that are intrinsically three-dimensional and thus most effectively taught in an immersive environment. The portable system allows taking the educational experience to rural and tribal sites where the underserved students could not afford the time or expense to travel to museums.  相似文献   

12.
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   

13.
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 ∝ γs 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   

14.
In the frame of the 2009 Mars Science Laboratory (MSL) mission a new sample preparation system (SPS) compatible with gas chromatography–mass spectrometry (GC–MS) has been developed for the in situ analysis of complex organic molecules in the Martian soil. The goal is to detect, if they exist, some of the key compounds that play an important role in life on Earth including carboxylic acids, amino acids and nucleobases.  相似文献   

15.
基于LuGre模型的电液加载系统摩擦补偿   总被引:4,自引:2,他引:2  
为了提高电液加载系统控制精度,针对摩擦问题提出了基于LuGre摩擦模型的前馈补偿方法.建立了用于摩擦仿真分析和补偿器设计的电液加载系统数学模型;通过实验获取并分析了相关的摩擦数据;基于实验数据进行LuGre模型参数辨识,把LuGre模型和辨识结果引入电液加载系统数学模型,并进行仿真结果与实际摩擦数据的对照,证明了LuGre摩擦模型的准确性.设计前馈补偿器,进行了实验对比,实验结果表明前馈补偿器可将摩擦产生的控制误差有效地降至未补偿时的30%左右.   相似文献   

16.
Various aerial platforms intended for long endurance survey of the Titan surface are presented. A few novel concepts are introduced, including a heated methane balloon and a balloon with a tethered wind turbine. All the concept options are predicted to have lower scientific payload fractions than the Huygens probe. It is concluded that the selection of the best aerial platform option depends on more accurate mass estimates and a clear decision on whether, or not, in situ surface composition measurements are required in conjunction with aerial remote sensing.  相似文献   

17.
To understand the evolution of organic molecules involved in extraterrestrial environments and with exobiological implications, many experimental programs in the laboratory are devoted to photochemical studies in the gaseous phase as well as in the solid state. The validity of such studies and their applications to extraterrestrial environments can be questioned as long as experiments conducted in space conditions, with the full solar spectrum, especially in the short wavelength domain, have not been implemented. The experiments that are described here will be carried out on a FOTON capsule, using the BIOPAN facility, and on the International Space Station, using the EXPOSE facility. Vented and sealed exposition cells will be used, which will allow us to study the chemical evolution in the gaseous phase as well as heterogeneous processes, such as the degradation of solid compounds and the release of gaseous fragments.  相似文献   

18.
The space-borne observatories CoRoT (Convection Rotation and planetary Transits) and Kepler have provided photometric time series data of unprecedented precision for large numbers of stars. These data have revolutionized the fields of transiting exoplanets and asteroseismology. In this review some important asteroseismic results obtained using data from the CoRoT and Kepler space missions concerning stars that show solar-like oscillations are discussed. These results comprise, among others, measurements of the location of the base of the convection zone and helium second-ionization zone in main-sequence stars, the presence (or not) of core-helium burning in red-giant stars, as well as differential rotation in these stars.  相似文献   

19.
Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter’s icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.  相似文献   

20.
Heliophysics is a new research field that explores the Sun–Solar System Connection; it requires the joint exploitation of solar, heliospheric, magnetospheric and ionospheric observations.  相似文献   

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