大型空间环境模拟器设备液氮制冷系统杜瓦管的研制

液氮系统是大型空间环境模拟设备中的主要分系统之一，在大型空间模拟器的液氮流程中，采用杜瓦管供液的结构形式，也是近年来国外大型空间模拟器中所采用的主要供液方式，介绍了大型空间环境模拟器液氮制冷系统中杜瓦管的作用、结构、使用情况及特点，并根据现场调试，维护等自身因素限制，设计了一种比较简便实用的测试真空试件，经过现场对杜瓦管的调试验收，使杜瓦管的真空性能得到保证，经历了多项试验，杜瓦管始终处于良好使用状态，方便而可靠地保证了对系统，热沉等分系统的供液。     

大型空间环境模拟设备的气氦制冷系统

介绍了大型空间环境模拟设备的气氦制冷系统,说明了气氦系统的作用、工作原理及组成,并与同类空间环境模拟设备的气氦制冷系统进行了比较与分析。     

大型空间环境试验设备中的低温技术

对国内外大型空间环境模拟设备中的低温技术应用情况进行了介绍。重点介绍了我国一台大型空间环境试验设备中的低温技术应用情况介绍了低温技术对大型空间环境设备性能的影响。对大型空间环境模拟设备中的低温传热和流动现象进行了讨论。     

大型空间环境模拟试验设备的检漏

空间环境模拟试验设备属于大容器范围,为了保证大型空间环境模拟试验设备的密封性能,像所有大容器一样,仅仅在设备加工阶段或安装完毕后去进行检漏是远远不够的。大型空间环境模拟试验设备的检漏,应贯穿于设备设计、零部件的加工、设备的安装、调试的各个阶段,并提出了各阶段检漏工作的具体内容。对该设备的泄漏检测主要采用氦质谱检漏技术,如喷吹法、真空检漏盒法以及氦罩法等。针对大容器检漏中灵敏度不足的问题,在总漏率的测试中提出了真空室累积法,并详细介绍了其测试步骤。     

红外目标旋转模拟器校准方法的研究设想

文章简要介绍了红外目标旋转模拟器的结构组成、工作原理,给出了红外目标旋转模拟器的目标温度、平均角速度、角速度波动的校准方法,该校准方法能为光电设备的量值溯源提供解决方案.     

标准红外目标模拟器辐照度验证

红外目标模拟器广泛应用于红外技术上,为了能对红外目标模拟器进行校准,采用了标准红外目标模拟器。从保证红外辐射量值的准确性和有效传递出发,有必要对标准红外目标模拟器的输出辐度进行验证,中给出了验证方法和实验结果,并就一些影响因素进行了讨论。     

用于电离层环境模拟器的ECR等离子体源

为了经济地考验空间电离层等离子体对处于其中的飞行器表面的作用，需要在地面建立等离子体环境模拟器。本就是为空间电离层环境模拟研制的扩散型极低气压，低电子温度和极低密度的紧凑型电子回旋共振等离子体源的研制，结果显示：在等离子体源下游50cm处，在10^-2-10^-3Pa范围内获得了电子温度低于5eV，密度在10^4-10^6cm^-3范围内的较为均匀的等离子体束流，基本满足了空间环境模拟实验的需要。     

日本的一种空间环境模拟试验容器

以日本的一台中型空间环境模拟试验容器为例,介绍了空间环境模拟试验的目的、空间环境的模拟方法、装置的构成。在介绍这台设备的内容中,介绍了真空容器、抽气系统、低温流程、太阳光模拟装置、测量控制系统。     

用于电离层环境模拟器的ECR等离子体源

为了经济地考验空间电离层等离子体对处于其中的飞行器表面的作用,需要在地面建立等离子体环境模拟器。本文就是为空间电离层环境模拟器研制的扩散型极低气压、低电子温度和极低密度的紧凑型电子回旋共振等离子体源的研制。结果显示在等离子体源下游50cm处,在10-2～10-3Pa范围内获得了电子温度低于5eV,密度在104～106cm-3范围内的较为均匀的等离子体束流,基本满足了空间环境模拟实验的需要。     

太阳能模拟器滤光片的研制

太阳能模拟器作为研究航天科技卫星空间环境模拟和太阳能电池的检测与标定的必要模拟设备,越来越受到人们的关注,其中,模拟器滤光片(AM1.5)是太阳能模拟器的关键元件。本文依据标准大气光谱和标准氙灯的光谱曲线,得到了AM1.5型太阳能模拟器滤光片的透射率光谱曲线。在此基础上用TFC膜系软件对该滤光片的膜系进行了设计、优化,并对该膜系进行了镀制工艺研究。光谱测试结果表明,所研制的滤光片的中心波长950 nm处的透射率T=15%,半宽度350 nm;400~750 nm波段内,平均透射率Ta≥95%,1200~1400 nm内平均透射率Ta≥92%。光谱辐照度测试结果表明,其辐照匹配度在0.89~1.09之间,达到A类滤光片要求。     

膨胀石墨蠕虫的红外衰减性能研究

本文报道了不同膨胀容积的膨胀石墨蠕虫的红外衰减实验结果,并将其与常用的红外干扰材料--天然鳞片状石墨的红外衰减性能作了对比研究.结果表明:膨胀石墨蠕虫比天然鳞片状石墨具有更好的红外衰减性能.膨胀石墨蠕虫的红外衰减性能与该材料的膨胀容积有关,膨胀容积大,红外衰减性能好.     

石墨气溶胶粒度分布及远红外消光因子研究

在烟幕试验箱中测试了不同湿度条件下超细石墨气溶胶的粒子分布及其随时间变化的规律。根据Mie散射理论计算了石墨气溶胶粒子对8～14μm远红外的消光因子。分析表明,石墨气溶胶的粒度随着分散时间延长和空气相对湿度减小而变小。小尺度的石墨气溶胶粒子对8～14μm红外的消光效率因子非常小,但随着气溶胶粒子直径的增加,消光效率因子显著变大并趋于稳定。直径大于2.5μm的石墨气溶胶粒子均能够对8～14μm远红外产生良好的消光效果。     

Electrical conductivity and optical properties of polyaniline intercalated graphite oxide nanocomposites

Layered graphite oxide is used as host material for the synthesis of conducting polymer intercalated nanocomposites. Powder X-ray diffraction, Fourier transform infrared, and UV-VIS absorption spectra indicate the formation of polyaniline within the interlamellar spaces of graphite oxide. The red shift of UV-VIS absorption associated with graphite oxide is found. The direct current (dc) conductivity increases by about three orders of magnitude compare with pristine graphite oxide. The temperature dependence dc conductivity of the nanocomposite follows Mott's three-dimensional variable range hopping. The alternating current (ac) conductivity suggests correlated barrier hopping of conduction process. The conductivity relaxation time varies in the range of 10(-5)-10(-7) Sec.     

Research on the hot deformation behavior and graphite morphology of spheroidal graphite cast iron at high strain rate

The hot deformation behavior of spheroidal graphite cast iron (SGCI) was investigated quantitatively from 600 °C to 950 °C at high strain rate of 10 s⁻¹ by compression tests on a Gleeble-1500 simulator. The results show that the peak strain increases gradually with increasing deformation temperatures in the range of 600–800 °C and decreases when the temperature is raised to 800 °C and above. The optimum deformation temperature range is determined at 700–900 °C. The graphite particles become spindles or flakes after deformation, even some graphite collapse in the compressed specimens with about 0.7 peak strains. The graphite area fraction decreases as the temperature increases, at the same time, the high peak strain promotes the dissolving of carbon.     

新型固体润滑剂──氟化石墨的制备与性能的研究

通过电解熔盐KF·ZHF制取氟气,再将氟气与石墨在500℃时进行反应,从而制备了氟化石墨新材料．其密度值为2．53g／cm³、电阻率为3.1×10³Ω·cm,颜色为灰白色,在波数1219、1350cm^－1附近有F-C共价键红外光谱吸收峰．对氟化石墨、石墨、二硫化钼进行摩擦因数测试,结果表明：氟化石墨摩擦因数最小．还讨论了氟化石墨的一些特殊性能和工艺条件．     

源气体流量比对F-DLC薄膜结构的影响

以高纯石墨作靶，CHF3/Ar作源气体采用反应磁控溅射法制备出了氟化类金刚石（F-DLC）薄膜。拉曼光谱表明，CHF3相对流量的增加会引起薄膜的D峰与G峰强度之比I（D）/I（G）减小，晶粒增大，芳香环结构出例下降。红外吸收光谱分析证实了这些推论，指出这是由于薄膜中氟含量上升的结果。     

Visible and infrared optical properties of stacked cone graphite microtubes

The absorptive and scattering optical properties of heat-treated, vapor-grown, graphite microtubes consisting of nanotubes in a "stacked cone" configuration were investigated through the visible and infrared wavelengths using photoacoustic and other spectrometric techniques. However, computations of these properties involved uncertainties that were not easily resolved; the appropriate dielectric coefficients were presumed to be a combination of the published values for the distinct orientations of graphite, but the correct proportions are not evident and none of the reasonable choices produced satisfactory agreement (within the measurement limits of error). Since both of the primary components of the extinction were measured, the appropriate computational codes were employed in reverse to compute the dielectric coefficients for the graphite microtubes. Differences, primarily for the imaginary index, are most distinct for visible and near infrared wavelengths; in this wavelength region, the imaginary index falls progressively to less than half that for the computed mixture.     

Synthesis and Characterization of Flexible Polypyrrole/Exfoliated Graphite Composite via a New Method of Ultrasonic Assistance—Thermal Expansion at Low Temperature

Polypyrrole/exfoliated graphite composite was synthesized by expandable graphite, pyrrole and sodium dodecylbenzenesulfonate, via a new method of ultrasonic assistance—thermal expansion at low temperature. At the same time, the composite was characterized by scanning electron microscope and Fourier Transform infrared spectroscopy. The results exhibited that expandable graphite wrapped by polypyrrole could be prepared in the ultrasonic assistance and the composite synthesized in the thermal expansion. The results also showed that the composite provided with the wormlike morphology and the structure of exfoliated graphite wrapped by polypyrrole and polypyrrole would be oxidized while the expansion temperature was higher than at 350°C. This shows that the method not only is credible but also the especial morphology and structure indicate applications in some fields.     

Super-high interlayer spacing of graphite oxide obtained by γ-ray irradiation in air

We produced a type of graphite oxide with the interlayer spacing of 2.09 nm by treating conventional graphite oxide with γ-rays at an absorbed dose of 200 kGy in air. The expansion of interlayer distance should be attributed to the increased amounts of topological defects and then the improved steric hindrance between interlayers. Due to the decomposition of water molecules in graphite oxide by γ-rays, the reductive species were produced so that graphite oxide was partially reduced. It is also speculated to be the main mechanisms for alteration of oxygen groups. The change of carbon chain structures and oxygen groups were further supported by X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. This simple and effective method of making graphite oxide with d-spacing of 2.09 nm by irradiating it in air is of interest not only for its easier intercalation and exfoliation than pristine one, but also for its potential to prepare graphene sheets with high percent of monolayers.