航天中的人体热舒适研究
发布时间：2018-09-14 06:42
【摘要】：航天器密闭乘员舱内热环境是人类进军空间不可回避的环境要素。它不仅影响着航天员的健康和舒适，更与航天员的工作效率、物质能量流的循环密切相关。舱内热环境对人的热舒适性影响和其评价是航天器工程设计和航天飞行任务物质能量循环设计的关键环节之一。 航天飞行中失重对人体热调节的影响主要表现为机体皮肤血管舒张反应能力下降和核心体温的升高；而且自然对流的消失和低风速等飞行因素造成的机体与周围环境热交换能力下降，会进一步扰乱航天员的热平衡和热舒适。这些都可能对航天员的身心健康、工作生活以及包括舱外活动（Extravehicular activity, EVA）和应急逃逸等的航天活动产生不利影响，因而维持航天员在太空环境下，特别是长期飞行任务中的体温恒定与热舒适尤为重要。目前国内外载人航天器热环境的工程设计均基于稳态热舒适理论，舱内空气的流动依靠恒速通风（Artificial constant air flow, CAF）的风扇提供。一份“和平号”空间站研究总结报告指出，“失重消除了气体自然对流，也对机体温度的产生和维持产生了影响”，通过对和平号空间站上28个批次长期考察组驻站期间热环境状态进行评价，证明乘员舱普遍存在着热环境控制不良的状态，甚至在第23次考察任务期间由于座舱温度过高，乘组全体人员出现了不同程度的体温升高（最高体温达37.5℃）。最近的研究发现，与CAF相比，自然风或仿自然风（Simulated natural air flow, SNAF）产生的动态热舒适环境可有效增强人体的散热和冷感觉，并改善可接受性。那么，前瞻性探索SNAF对失重状态人体散热和核心体温维持的作用很有必要。 航天环境下人体热舒适维持与调整的重要前提是客观真实地评价热环境的舒适性。热舒适是人体暴露于热环境中基于自主性体温调节出现的心理感知结果，人体主观热反应会受生理体温调节活动的影响。但迄今为止，主观热反应与生理指标之间的有效对应关系，仍未完全建立。我国现有的航天热舒适评价体系主要通过主观问卷的方式，调查航天员在轨期间的热感觉和舒适程度，其评价结果在很大程度上会受到个体掩饰、航天心理因素、天地通讯等的限制和影响，其时效性和准确性受到一定的影响。因此，充分利用在轨的生理信息监测资源，对人体整体热舒适性状态进行主客观结合地评价，对于实时、准确地掌握航天员个体的热舒适性及健康状态，进而提出热环境调节建议具有十分重要的意义。特别是对于出舱活动状态下人体代谢负荷、健康状态的评估，具有直接的指导价值。为此，必须开展航天器密闭舱内人体的主观热反应与热效应敏感生理指标的有效对应关系研究，建立生理与主观指标相结合的评价模型。 在环境相同的情况下，由于性别、生活地域、工作生活方式、基础能量代谢率等个体因素的差异，人体热舒适性感受并不一致。人体能量代谢率（Energy metabolismrate, EMR）即单位时间人体的产热量，不仅是热舒适评价模型和热平衡方程中的重要个体参数，而且还是载人航天器热环境控制工程设计的参考依据。对于飞行乘组这个有限的群体，有必要准确了解其个体的能量代谢状态，为航天器热环境评价和热舒适性研究提供支持。 因此，本课题的研究目的如下：1）探索相同平均风速的SNAF是否较CAF更能有效维持模拟失重状态人体的体温恒定和热舒适；2）探讨密闭气候室内人体主观热反应与生理反应的关系，筛选航天活动时可以反映热舒适的敏感生理指标；3）探索建立模拟失重状态下的双标记水（Doubly labeled water, DLW）和改善心率（Heartrate, HR）估测EMR评价方法，分别提高航天飞行和EVA条件下EMR估测准确性。 为实现上述研究目的，本课题采取以下实验方法： 首先，以30天-6°头低位卧床模拟微重力的生理效应，以各国航天器普遍采用的热舒适温度23℃为背景环境温度，7名男性受试者分别在卧床前3天和卧床第29天，暴露于对照无风环境（CON，平均风速0.05m/s，暴露时间为50min）及采用动态送风装置产生的SNAF（=0.2m/s,30min）和CAF（=0.2m/s,30min）环境中。分析仿自然通风和恒速机械通风下，卧床状态人体的直肠温度（Rectal temperature,Tre）、皮肤温度（skin temperature, Tsk）、皮肤血流传导率（Cutaneous vascularconductance, CVC）、热感觉投票（Thermal sensation vote, TSV）等热反应指标的变化。 其次，在密闭气候室设置34℃、31℃、28℃、26℃、23℃和20℃6种温度环境。实验以15名男性青年为受试对象，测量受试者在密闭室60min静坐状态下的Tsk、Tre、心率变异性（Heart rate variability, HRV）和EMR等生理指标，同时受试者填写TSV和热舒适投票（Thermal comfort vote, TCV）等主观问卷，分析不同环境下的生理指标与主观热反应变化及两者的相关程度； 最后，课题关注了热舒适评价重要参数EMR的估测方法。1）以30天头低位卧床模拟失重效应，依据DLW服用方法将21名男性受试者分为3组：15天测量周期的常规剂量法（A组）、20天测量周期的补充剂量法（B组）和1.5倍常规剂量法（C组），分析不同服用方法所测EMR的质量控制准确性，建立模拟失重状态人体的DLW估测方法；之后按照在轨飞行任务安排，3名受试者（2名男性，1名女性）在组合体实验舱生活工作13天。分别采用常规剂量DLW法和氧气消耗法估测密闭舱内受试者的平均EMR，并进行结果的比较，进一步确定DLW法的有效性和准确性；2）通过测量10名男性受试者在跑台、上肢和下肢自行车功量计三种运动方式下的EMR和HR等生理指标，，分别建立个体在不同运动方式和整体运动方式下EMR和HR的线性回归方程，并采用验证性实验评价两种方法估测EMR的准确性和估测误差率。 本研究的主要结果和发现如下： 1.仿自然风对模拟失重人体热调节的影响 1）随着卧床时间延长，受试者静息状态腋温（Axillary temperature, Taxil）逐渐升高，并在第15天后具有显著性差异（P 0.05），其中在第20天升高了0.37℃。HR、舒张压、收缩压及静息状态氧耗量无显著变化（P0.05）；卧床后，受试者体重减轻约1.7kg（P 0.01）；排尿量在卧床期间并未发生明显改变，但受试者的饮水量在卧床第1天出现显著下降（P 0.01）； 2）对照环境下，经过29天卧床，Tre升高了约0.18℃（P 0.05）。与卧床前对照相比，卧床后CAF通风环境下Tre仍然显著升高，但卧床后SNAF通风环境下Tre无显著差异（P0.05），这提示在SNAF通风暴露下，核心体温接近卧床前对照水平； 3）与CAF相比，SNAF的湍流度（Turbulence intensity, Tu)更高，这可能提高了机体与周围环境的对流散热，抑制了卧床导致的Tre升高，维持了体温的相对恒定； 4）经过29天卧床，平均皮肤温度（Mean skin temperature,）呈下降趋势，但无统计学差异。卧床后，与CAF或CON环境相比，SNAF环境下的和CVC显著降低（P 0.05），表明SNAF对人体的散热效果更强； 5）与卧床前相比，卧床后对照环境下的TSV未见显著差别；卧床前，CON、SNAF和CAF气流模式的TSV间均无显著差异。卧床后，与CON和CAF环境相比，SNAF环境下的TSV显著降低（P 0.05）。三种环境的TSV值均在“稍凉”和“中性”之间。2.密闭环境人体热舒适生理研究 1）TSV随周围实测环境温度而上升，并且与环境温度相关程度很高（R2=0.99）；受试者静坐状态下，感到热中性的环境温度约25.78℃；TCV随着环境温度的上升呈现倒“U”型分布，曲线顶点对应环境温度约为26℃； 2）Tsk和HRV随环境温度变化较为显著，而Tre、额足温差和EMR随环境温度变化不显著；其中与躯干Tsk相比，肢端Tsk随环境温度变化更为显著；多重检验表明，上臂和前臂Tsk更易受到环境温度的影响； 3）随着环境温度上升，HRV的LFnorm值（低频标准化值）和LF/HF比值呈现升高趋势，HFnorm（高频标准化值）呈现降低趋势；机体EMR的最低值出现在热中性环境附近； 4）Tsk、HRV、EMR和Tre分别与TSV具有显著相关性（P 0.05），其中上臂、前臂的Tsk和与热感觉的密切程度最高（r0.82）；受试者感到最舒适时的为33.42°C。 3.航天热舒适环境人体能量代谢的估测方法研究 1）A组、B组和C组三种DLW服用方案获得的人体模拟失重状态能量代谢数据均符合质量控制准确性要求，分别适合15天至20天的飞行任务，受试者平均能量代谢率为(433.3±79.2) kJ/h~(512.5±29.2) kJ/h； 2）采用氧气消耗法估测密闭组合体舱内受试者在全周期任务段的平均能量代谢率为417.36kJ/h，与双标记水法估测结果（408.89kJ/h）接近；受试者活动水平介于静息和轻度活动之间； 3）不同的运动方式下的个体EMR-HR线性关系有一定的差异性。完成同样负荷运动时所对应的心率，跑台最低，上肢自行车功量计最高。采用基于运动方式的估测方法，HR与EMR相关程度较不加区分的分析方法更为密切（r=0.97），而且估测误差更低（P 0.05），这表明基于运动方式的分析可提高运动状态下HR估测个体EMR的准确性。 本研究得到以下结论： 1）卧床模拟失重可导致人体静息状态下Tre的升高，这可能与皮肤血流量改变，机体表面对流、蒸发散热降低有关。 2）与恒速机械风相比，仿自然风可更为有效地维持模拟失重状态下的核心体温恒定，热感觉接近中性。仿自然风维持模拟失重状态核心体温的机制可能与高湍流度增加了身体与周围环境的对流散热有关； 3）密闭舱室环境中，人体上臂、前臂Tsk及与主观热反应关系最为密切，可以作为航天员空间飞行热舒适的客观评价指标； 4）首次在我国建立了模拟失重状态人体EMR的DLW估测方法，其中常规剂量服用方案可满足测试周期为15天的航天飞行任务；与补充剂量方案相比，对于测试周期为20天的飞行任务，1.5倍常规剂量服用方案更利于在空间任务中进行实施； 5）航天员运动状态或EVA期间，基于运动方式改进的HR-EMR回归方程，可降低心率法估测个体能量代谢的误差，提高估测的准确性。
[Abstract]:The thermal environment in the enclosed cabin of a spacecraft is an unavoidable environmental factor for human beings to march into space. It not only affects the health and comfort of the astronauts, but also is closely related to the work efficiency of the astronauts and the cycle of material and energy flow. One of the key links in material energy cycle design.
The effects of weightlessness on human thermal regulation during space flight are mainly manifested by the decrease of skin vasodilation and the increase of core body temperature, and the loss of natural convection and the decrease of heat exchange between the body and the surrounding environment caused by low wind speed will further disturb the thermal balance and thermal comfort of astronauts. It may have adverse effects on astronauts'physical and mental health, work and life as well as space activities including extravehicular activities (EVA) and emergency escape. Therefore, it is very important to maintain the constant temperature and thermal comfort of astronauts in space environment, especially in long-term missions. The engineering design of the environment is based on the theory of steady-state thermal comfort. The flow of air in the cabin is provided by a fan with constant velocity ventilation (CAF). Evaluations of the thermal environment during the stationing of 28 batches of long-term crew on the space station proved that the crew cabin was generally in a state of poor thermal environment control, and even during the 23rd mission due to excessive cabin temperature, crew members of the crew experienced varying degrees of temperature rise (the highest body temperature reached 37.5 degrees Celsius). Recent studies It is found that compared with CAF, the dynamic thermal comfort environment produced by natural wind or Simulated natural air flow (SNAF) can effectively enhance the human body's heat dissipation and cold sensation, and improve acceptability.
The important premise of maintaining and adjusting human thermal comfort in space environment is to evaluate the comfort of thermal environment objectively and truly. The existing evaluation system of space thermal comfort in China mainly investigates the thermal sensation and comfort degree of astronauts in orbit by means of subjective questionnaires. The evaluation results will be limited and influenced to a great extent by individual disguise, space psychological factors, Space-earth communication and so on. Therefore, it is of great significance to make full use of on-orbit physiological information monitoring resources to evaluate the overall thermal comfort state of the human body both subjectively and objectively, so as to grasp the thermal comfort and health status of the astronauts in real time and accurately, and then put forward suggestions for adjusting the thermal environment. Therefore, it is necessary to study the effective relationship between the subjective thermal response and the sensitive physiological indexes of thermal effect in the spacecraft enclosed cabin, and establish an evaluation model combining physiological and subjective indexes.
In the same environment, human thermal comfort sensation is not consistent because of the differences of individual factors such as sex, living area, working life style and basic energy metabolic rate. Individual parameters are also the reference for the design of thermal environment control engineering for manned spacecraft. It is necessary to accurately understand the energy metabolism state of the flying crew, which is a limited group, so as to provide support for spacecraft thermal environment assessment and thermal comfort research.
Therefore, the research purposes of this topic are as follows: 1) to explore whether SNAF with the same average wind speed can maintain the body temperature stability and thermal comfort more effectively than CAF in simulated weightlessness; 2) to explore the relationship between the subjective thermal response and physiological response in the closed climate chamber, and to screen sensitive physiological indicators that can reflect thermal comfort in space activities; To explore the establishment of double labeled water (DLW) and improved heart rate (HR) EMR evaluation methods under simulated weightlessness, and to improve the accuracy of EMR estimation under space flight and EVA conditions, respectively.
In order to achieve the above research objectives, the following experimental methods are adopted in this study.
Firstly, the physiological effects of microgravity were simulated by 30-6 degrees head-down bed rest, and the thermal comfort temperature of 23 C, which is commonly used by spacecraft in various countries, was taken as the background environment temperature. Seven male subjects were exposed to the control windless environment (CON, average wind speed 0.05 m/s, exposure time 50 min) and the dynamic air supply device on the first 3 days and the 29th day of bed rest, respectively. SNAF (= 0.2m/s, 30min) and CAF (= 0.2m/s, 30min) were produced. Rectal temperature, Tre, skin temperature, Tsk, Cutaneous vascularity conductance (CVC), Thermal sensation vote (TS) were analyzed under natural ventilation and constant speed mechanical ventilation. V) changes in other thermal response indicators.
Secondly, six temperature environments were set up in the closed climate chamber, including 34, 31, 28, 26, 23, and 20. The physiological indexes of Tsk, Tre, HRV and EMR were measured in 15 male young people during 60 minutes of sitting in the closed climate chamber. At the same time, the subjects filled in TSV and Therm comfort voting. Subjective questionnaires such as Al comfort vote (TCV) were used to analyze the changes of physiological indices and subjective heat response in different environments and the correlation between them.
Finally, we focused on the estimation method of EMR, an important parameter of thermal comfort assessment. 1) 21 male subjects were divided into three groups according to the DLW method: 15-day routine dose method (group A), 20-day supplementary dose method (group B) and 1.5-fold routine dose method (group C) to analyze different doses. The DLW estimation method of simulated weightlessness was established by using the accuracy of quality control of EMR. Three subjects (2 males and 1 females) lived and worked for 13 days in the combined experimental cabin according to the on-orbit mission arrangement. The validity and accuracy of the DLW method were further confirmed by comparing the results. 2) By measuring the physiological indexes of EMR and HR of 10 male subjects in treadmill, bicycle ergometer of upper limb and lower limb, the linear regression equations of EMR and HR were established under different exercise modes and overall exercise modes, respectively. Confirmatory experiments evaluate two methods to estimate the accuracy of EMR and estimate the error rate.
The main findings and findings of this study are as follows:
1. the influence of imitation natural wind on the thermal regulation of simulated weightlessness
1) Axillary temperature (Taxil) in resting state increased gradually with the prolongation of bedtime, and there was a significant difference (P 0.05) after the 15th day. On the 20th day, Axillary temperature (Taxil) increased by 0.37 C. HR, diastolic blood pressure (DBP), systolic blood pressure (SBP) and oxygen consumption in resting state did not change significantly (P 0.05). Urine output did not change significantly during bed rest, but water intake decreased significantly on the first day of bed rest (P 0.01).
2) Tre increased about 0.18 ((P 0.05)) after 29 days in bed. Compared with the control group, Tre still increased significantly under CAF ventilation after bed rest, but Tre had no significant difference under SNAF ventilation after bed rest (P 0.05).
3) Compared with CAF, the Turbulence intensity (Tu) of SNAF is higher, which may increase the convective heat transfer between the body and the surrounding environment, inhibit the rise of Tre caused by bed rest, and maintain the relative constant body temperature.
4) After 29 days in bed, mean skin temperature (Mean skin temperature,) showed a downward trend, but there was no statistical difference. After lying in bed, compared with CAF or CON environment, SNAF environment and CVC significantly decreased (P 0.05), indicating that SNAF has a stronger heat dissipation effect on human body.
5) There was no significant difference in TSV between the two groups before and after bed rest; there was no significant difference in TSV between CON, SNAF and CAF before bed rest. After bed rest, TSV in SNAF was significantly lower than that in CON and CAF (P 0.05). TSV values in the three environments were between "slightly cool" and "neutral". 2. Physiologic study
1) TSV increased with the measured ambient temperature and had a high degree of correlation with ambient temperature (R2 = 0.99); the subjects felt thermal neutral ambient temperature at about 25.78 while the TCV showed an inverted U-shaped distribution with the increase of ambient temperature, and the corresponding ambient temperature at the top of the curve was about 26.
2) Tsk and HRV changed significantly with ambient temperature, while Tre, forehead-foot temperature difference and EMR did not change significantly with ambient temperature. Compared with trunk Tsk, limb Tsk changed more significantly with ambient temperature.
3) With the increase of ambient temperature, the LFnorm (low frequency standardized value) and LF / HF ratio of HRV increased, while HFnorm (high frequency standardized value) decreased. The lowest EMR value of organism appeared near the thermal neutral environment.
4) Tsk, HRV, EMR and Tre were significantly correlated with TSV (P 0.05). The Tsk of upper arm and forearm had the highest degree of intimacy with thermal sensation (r 0.82), and the subjects felt the most comfortable was 33.42 degree C.
3. estimation method of human body energy metabolism in space thermal comfort environment
1) The energy metabolism data of group A, group B and group C under three DLW regimens met the accuracy requirements of quality control, and were suitable for 15-20 days flight mission respectively. The average energy metabolism rate of subjects was (433.3 (79.2) kJ / H ~ (512.5 (29.2) kJ / h.
2) Oxygen consumption method was used to estimate the average energy metabolism rate of the subjects in the closed cabin during the whole cycle task period, which was 417.36 kJ/h, close to that of the double-labeled water method (408.89 kJ/h).
3) There is a certain difference in the EMR-HR linear relationship between individuals under different exercise modes. The heart rate corresponding to the same load exercise is the lowest on the treadmill and the highest on the bicycle ergometer. Low (P 0.05), indicating that exercise-based analysis can improve the accuracy of HR estimation of individual EMR.
The following conclusions are drawn:
1) Simulated weightlessness in bed can lead to the increase of Tre in resting state, which may be related to the change of skin blood flow, convection on the body surface, and the decrease of evaporation and heat dissipation.
2) Compared with the constant-speed mechanical wind, the simulated natural wind is more effective in maintaining the core body temperature under simulated weightlessness, and the thermal sensation is close to neutral.
3) In the enclosed cabin environment, the human upper arm, forearm Tsk and the subjective thermal response are most closely related, which can be used as an objective evaluation index of thermal comfort for astronauts in space flight.
4) The DLW estimation method of simulated weightlessness human EMR was established for the first time in China, in which the conventional dosage regimen could meet the requirements of a 15-day spaceflight mission.
【学位授予单位】：第四军医大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R852
本文编号：2241847
[Abstract]:The thermal environment in the enclosed cabin of a spacecraft is an unavoidable environmental factor for human beings to march into space. It not only affects the health and comfort of the astronauts, but also is closely related to the work efficiency of the astronauts and the cycle of material and energy flow. One of the key links in material energy cycle design.
The effects of weightlessness on human thermal regulation during space flight are mainly manifested by the decrease of skin vasodilation and the increase of core body temperature, and the loss of natural convection and the decrease of heat exchange between the body and the surrounding environment caused by low wind speed will further disturb the thermal balance and thermal comfort of astronauts. It may have adverse effects on astronauts'physical and mental health, work and life as well as space activities including extravehicular activities (EVA) and emergency escape. Therefore, it is very important to maintain the constant temperature and thermal comfort of astronauts in space environment, especially in long-term missions. The engineering design of the environment is based on the theory of steady-state thermal comfort. The flow of air in the cabin is provided by a fan with constant velocity ventilation (CAF). Evaluations of the thermal environment during the stationing of 28 batches of long-term crew on the space station proved that the crew cabin was generally in a state of poor thermal environment control, and even during the 23rd mission due to excessive cabin temperature, crew members of the crew experienced varying degrees of temperature rise (the highest body temperature reached 37.5 degrees Celsius). Recent studies It is found that compared with CAF, the dynamic thermal comfort environment produced by natural wind or Simulated natural air flow (SNAF) can effectively enhance the human body's heat dissipation and cold sensation, and improve acceptability.
The important premise of maintaining and adjusting human thermal comfort in space environment is to evaluate the comfort of thermal environment objectively and truly. The existing evaluation system of space thermal comfort in China mainly investigates the thermal sensation and comfort degree of astronauts in orbit by means of subjective questionnaires. The evaluation results will be limited and influenced to a great extent by individual disguise, space psychological factors, Space-earth communication and so on. Therefore, it is of great significance to make full use of on-orbit physiological information monitoring resources to evaluate the overall thermal comfort state of the human body both subjectively and objectively, so as to grasp the thermal comfort and health status of the astronauts in real time and accurately, and then put forward suggestions for adjusting the thermal environment. Therefore, it is necessary to study the effective relationship between the subjective thermal response and the sensitive physiological indexes of thermal effect in the spacecraft enclosed cabin, and establish an evaluation model combining physiological and subjective indexes.
In the same environment, human thermal comfort sensation is not consistent because of the differences of individual factors such as sex, living area, working life style and basic energy metabolic rate. Individual parameters are also the reference for the design of thermal environment control engineering for manned spacecraft. It is necessary to accurately understand the energy metabolism state of the flying crew, which is a limited group, so as to provide support for spacecraft thermal environment assessment and thermal comfort research.
Therefore, the research purposes of this topic are as follows: 1) to explore whether SNAF with the same average wind speed can maintain the body temperature stability and thermal comfort more effectively than CAF in simulated weightlessness; 2) to explore the relationship between the subjective thermal response and physiological response in the closed climate chamber, and to screen sensitive physiological indicators that can reflect thermal comfort in space activities; To explore the establishment of double labeled water (DLW) and improved heart rate (HR) EMR evaluation methods under simulated weightlessness, and to improve the accuracy of EMR estimation under space flight and EVA conditions, respectively.
In order to achieve the above research objectives, the following experimental methods are adopted in this study.
Firstly, the physiological effects of microgravity were simulated by 30-6 degrees head-down bed rest, and the thermal comfort temperature of 23 C, which is commonly used by spacecraft in various countries, was taken as the background environment temperature. Seven male subjects were exposed to the control windless environment (CON, average wind speed 0.05 m/s, exposure time 50 min) and the dynamic air supply device on the first 3 days and the 29th day of bed rest, respectively. SNAF (= 0.2m/s, 30min) and CAF (= 0.2m/s, 30min) were produced. Rectal temperature, Tre, skin temperature, Tsk, Cutaneous vascularity conductance (CVC), Thermal sensation vote (TS) were analyzed under natural ventilation and constant speed mechanical ventilation. V) changes in other thermal response indicators.
Secondly, six temperature environments were set up in the closed climate chamber, including 34, 31, 28, 26, 23, and 20. The physiological indexes of Tsk, Tre, HRV and EMR were measured in 15 male young people during 60 minutes of sitting in the closed climate chamber. At the same time, the subjects filled in TSV and Therm comfort voting. Subjective questionnaires such as Al comfort vote (TCV) were used to analyze the changes of physiological indices and subjective heat response in different environments and the correlation between them.
Finally, we focused on the estimation method of EMR, an important parameter of thermal comfort assessment. 1) 21 male subjects were divided into three groups according to the DLW method: 15-day routine dose method (group A), 20-day supplementary dose method (group B) and 1.5-fold routine dose method (group C) to analyze different doses. The DLW estimation method of simulated weightlessness was established by using the accuracy of quality control of EMR. Three subjects (2 males and 1 females) lived and worked for 13 days in the combined experimental cabin according to the on-orbit mission arrangement. The validity and accuracy of the DLW method were further confirmed by comparing the results. 2) By measuring the physiological indexes of EMR and HR of 10 male subjects in treadmill, bicycle ergometer of upper limb and lower limb, the linear regression equations of EMR and HR were established under different exercise modes and overall exercise modes, respectively. Confirmatory experiments evaluate two methods to estimate the accuracy of EMR and estimate the error rate.
The main findings and findings of this study are as follows:
1. the influence of imitation natural wind on the thermal regulation of simulated weightlessness
1) Axillary temperature (Taxil) in resting state increased gradually with the prolongation of bedtime, and there was a significant difference (P 0.05) after the 15th day. On the 20th day, Axillary temperature (Taxil) increased by 0.37 C. HR, diastolic blood pressure (DBP), systolic blood pressure (SBP) and oxygen consumption in resting state did not change significantly (P 0.05). Urine output did not change significantly during bed rest, but water intake decreased significantly on the first day of bed rest (P 0.01).
2) Tre increased about 0.18 ((P 0.05)) after 29 days in bed. Compared with the control group, Tre still increased significantly under CAF ventilation after bed rest, but Tre had no significant difference under SNAF ventilation after bed rest (P 0.05).
3) Compared with CAF, the Turbulence intensity (Tu) of SNAF is higher, which may increase the convective heat transfer between the body and the surrounding environment, inhibit the rise of Tre caused by bed rest, and maintain the relative constant body temperature.
4) After 29 days in bed, mean skin temperature (Mean skin temperature,) showed a downward trend, but there was no statistical difference. After lying in bed, compared with CAF or CON environment, SNAF environment and CVC significantly decreased (P 0.05), indicating that SNAF has a stronger heat dissipation effect on human body.
5) There was no significant difference in TSV between the two groups before and after bed rest; there was no significant difference in TSV between CON, SNAF and CAF before bed rest. After bed rest, TSV in SNAF was significantly lower than that in CON and CAF (P 0.05). TSV values in the three environments were between "slightly cool" and "neutral". 2. Physiologic study
1) TSV increased with the measured ambient temperature and had a high degree of correlation with ambient temperature (R2 = 0.99); the subjects felt thermal neutral ambient temperature at about 25.78 while the TCV showed an inverted U-shaped distribution with the increase of ambient temperature, and the corresponding ambient temperature at the top of the curve was about 26.
2) Tsk and HRV changed significantly with ambient temperature, while Tre, forehead-foot temperature difference and EMR did not change significantly with ambient temperature. Compared with trunk Tsk, limb Tsk changed more significantly with ambient temperature.
3) With the increase of ambient temperature, the LFnorm (low frequency standardized value) and LF / HF ratio of HRV increased, while HFnorm (high frequency standardized value) decreased. The lowest EMR value of organism appeared near the thermal neutral environment.
4) Tsk, HRV, EMR and Tre were significantly correlated with TSV (P 0.05). The Tsk of upper arm and forearm had the highest degree of intimacy with thermal sensation (r 0.82), and the subjects felt the most comfortable was 33.42 degree C.
3. estimation method of human body energy metabolism in space thermal comfort environment
1) The energy metabolism data of group A, group B and group C under three DLW regimens met the accuracy requirements of quality control, and were suitable for 15-20 days flight mission respectively. The average energy metabolism rate of subjects was (433.3 (79.2) kJ / H ~ (512.5 (29.2) kJ / h.
2) Oxygen consumption method was used to estimate the average energy metabolism rate of the subjects in the closed cabin during the whole cycle task period, which was 417.36 kJ/h, close to that of the double-labeled water method (408.89 kJ/h).
3) There is a certain difference in the EMR-HR linear relationship between individuals under different exercise modes. The heart rate corresponding to the same load exercise is the lowest on the treadmill and the highest on the bicycle ergometer. Low (P 0.05), indicating that exercise-based analysis can improve the accuracy of HR estimation of individual EMR.
The following conclusions are drawn:
1) Simulated weightlessness in bed can lead to the increase of Tre in resting state, which may be related to the change of skin blood flow, convection on the body surface, and the decrease of evaporation and heat dissipation.
2) Compared with the constant-speed mechanical wind, the simulated natural wind is more effective in maintaining the core body temperature under simulated weightlessness, and the thermal sensation is close to neutral.
3) In the enclosed cabin environment, the human upper arm, forearm Tsk and the subjective thermal response are most closely related, which can be used as an objective evaluation index of thermal comfort for astronauts in space flight.
4) The DLW estimation method of simulated weightlessness human EMR was established for the first time in China, in which the conventional dosage regimen could meet the requirements of a 15-day spaceflight mission.
【学位授予单位】：第四军医大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R852
【参考文献】
相关期刊论文 前3条
1 孙京霞,白延强;心率变异分析方法的研究进展[J];航天医学与医学工程;2001年03期
2 邱曼,刘武,刘钢,文计福,刘国印,常绍勇;模拟失重条件下体温调节的特点[J];航天医学与医学工程;1997年03期
3 庞诚,顾鼎良;失重因素对航天员体温调节影响的分析[J];中国空间科学技术;2001年03期
本文编号：2241847
本文链接：https://www.wllwen.com/yixuelunwen/yxlw/2241847.html
最近更新
教材专著
