航天应用的制冷机系统

介绍冷却４×２２ 元 Ｈｇ Ｃｄ Ｔｅ 红外探测器的集成组件的斯特林制冷系统。这是一种单级的牛津型的斯特林制冷机。其特点是采用膜片弹簧支撑、音圈电机驱动、差动变压器的位移传感器和间隙动密封技术。制冷机的最低制冷温度４３ Ｋ, 降温时间２０ ｍ ｉｎ, 其压缩机功耗约３０ Ｗ。制冷机系统采用双机屏蔽轴向对置排列, 以减小系统机械振动和对探测器的电磁干扰。制冷机通过柔性冷链（汇流排）冷却红外探测器组件。系统在８０ Ｋ 时对探测器提供的冷量大于３０ ｍ Ｗ,制冷机功耗４５ Ｗ。冷链温差为２５ Ｋ, 探测器等效温度灵敏度０２ Ｋ。     

自由活塞斯特林制冷机的研究与应用进展

对自由活塞斯特林制冷机(FPSC)的发展历史以及当前的研究进展进行总结,比较了自由活塞斯特林制冷机与分置式斯特林制冷机的性能,结果显示自由活塞斯特林制冷机的相对卡诺效率明显高于分置式斯特林制冷机。自由活塞斯特林制冷机具有高效、紧凑、制冷温区广等优势,分别从航天、超导、低温冰箱、家用制冷等方面详细总结了自由活塞斯特林制冷机应用情况。最后,根据自由活塞斯特林制冷机的发展现状,提出了一些有用的建议,对自由活塞斯特林制冷机的发展及应用具有一定指导意义。     

脉管型斯特林制冷机的实验研究

对脉管型斯特林制冷机用于普冷的可行性进行了分析研究。用实验的方法对脉管到斯特林制冷机和单纯的斯特林制冷机的性能进行了对比，得出了在２４５Ｋ以上温区脉管型斯特林制冷机的性能优于单纯的斯特林制冷机的重要结论．对小孔和脉管长度变化对脉管型斯特林制冷机性能的影响进行了讨论．     

斯特林制冷机真空环境热模拟试验研究

为了验证空间斯特林制冷与辐射制冷、实现复合制冷系统的可行性,获取斯特林制冷机在真空条件下的散热情况,进行了斯特林制冷机空间真空环境热模拟试验。试验结果表明,真空条件下斯特林制冷机的散热是影响制冷机性能的重要因素。     

番禺水色在文创产品设计研发中的应用

目的 立足番禺水色民俗艺术,分析当前番禺水色文创产品现状,深入挖掘番禺水色艺术元素及文化内涵,探索番禺水色岭南民俗艺术文创产品设计方法与案例。方法 综合运用层次分析法、符号分析法等方法,提炼番禺水色文化符号作为设计元素与生活产品相结合的视觉语言,设计既蕴含番禺水色艺术特色又兼具现代时尚元素的文创产品,并在实践中予以运用。结论 番禺水色是独具岭南地域特色的行为文化,通过对番禺水色艺术的造型、色彩、精神等元素进行梳理归纳,巧妙运用于灯具设计,为番禺水色文创产品融入消费者生活找到契合点。     

星载辐射制冷器地面液氮制冷装置研制

介绍了液氮制冷装置的设计原则,技术指标与要求,绝热结构,绝热材料,抽真空工艺的选择及各项性能试验,试验结果表明,该制冷装置具有真空寿命长,无振动,无电磁干扰,等优点,是星载红外多光谱扫描仪理想的地面制冷设备,也是一种工作波长在８－１４μｍ范围红外探测器极佳的制冷源。     

基于DSP的星载小型化斯特林制冷机控制器设计

斯特林制冷机控制器对制冷机性能有很大影响。介绍了基于DSP系统的斯特林制冷机控制器设计,主要包括硬件、软件设计,为进一步实现斯特林制冷机的自适应控制打下较好的基础。     

斯特林冷冻机

1.前 言 斯特林冷冻机的正确称呼应是“逆向斯特林循环的冷冻机”。这本是原动机循环,1816年由斯特朗德地区牧师斯特林(Reverend Robert Stirling)所发明。 所谓原动机或冷冻机,在于热和动力的输入输出或相反。输入热能输出动力谓之原动机;相反,由外部输入动力而吸取热量的谓之冷冻机。因此,一般的斯特林冷冻机就采用逆向斯特林循环。     

斯特林控制器的研制

斯特林控制器是根据斯特林制冷机在工作时需对多种物理量进行测控而研制的设备。较详细地介绍了斯特林控制器的设计与实测以及性能指标等     

HOT器件用自由活塞斯特林制冷机研究进展

自由活塞斯特林制冷机可用于红外探测器组件的冷却,具有振动小、寿命长等优点。随着红外探测器工作温度的提高(HOT器件),斯特林制冷机进入更小尺寸、更低质量、更高性能、更低功耗和更低成本的发展方向,即超小型斯特林制冷机。文章总结了近10年国内外超小型自由活塞斯特林制冷机的发展概况,并对超小型自由活塞斯特林制冷机的设计理念进行了介绍。     

Deep flow in the Madagascar-Mascarene Basin over the last 150,000 years

The SW Indian Ocean contains at least four layers of water masses with different sources: deep Antarctic (Lower Circumpolar Deep Water) flow to the north, midwater North Indian Deep Water flow to the south and Upper Circumpolar Deep Water to the north, meridional convergence of intermediate waters at 500-1500 m, and the shallow South Equatorial Current flowing west. Sedimentation rates in the area are rather low, being less than 1 cm ka(-1) on Madagascar Ridge, but up to 4 cm ka(-1) at Amirante Passage. Bottom flow through the Madagascar-Mascarene Basin into Amirante Passage varies slightly on glacial-interglacial time-scales, with faster flow in the warm periods of the last interglacial and minima in cold periods. Far more important are the particularly high flow rates, inferred from silt grain size, which occur at warm-to-cold transitions rather than extrema. This suggests the cause is changing density gradient driving a transiently fast flow. Corroboration is found in the glacial-interglacial range of benthic delta18O which is ca. 2 per thousand, suggesting water close to freezing and at least 1.2 more saline and thus more dense glacial bottom waters than present. Significant density steps are inferred in isotope stage 6, the 5e-5d, and 5a-4 transitions. Oxygen isotope data suggest little change by mixing in glacial bottom water on their northward path. Benthic carbon isotope ratios at Amirante Passage differ from glacial Southern Ocean values, due possibly to absence of a local productivity effect present in the Southern Ocean.     

RIEGL LMS-Z390i三维激光扫描仪测角精度评定方法研究

提出了一种新的三维激光扫描仪测角精度评定方法,用TM5100电子经纬仪建立角度基准,以RIEGL LMS-Z390i激光扫描仪观测的点云坐标反算出的角度作为观测值,在考虑轴系误差的影响基础上,建立了平差模型,通过最小二乘解算出激光扫描仪的水平、垂直测角精度分别为0.002 7°、0.001 5°,评定出该方法的可行性。     

电磁铸造与普通连续铸造2024铝合金的组织性能对比

采用电磁铸造技术和普通连续铸造技术铸造了2024变形铝合金，采用光学显微镜和扫描电镜分析了其显微组织，而且对其进行了固溶处理加人工时效。结果表明电磁铸造锭内部组织细小均匀，有高的硬度和良好的疲劳性能，电磁铸造试样的硬度大约是普通连续铸造铸坯的2倍，疲劳性能是普通连续铸造铸坯的3倍。电磁铸造铸坯还有良好的耐磨性，磨损失重量是普通连续铸造的一半。     

0.8～1微米分步重复投影光刻机

０．８～１微米分步重复投影光刻机中国科学院光电技术研究所承担的国家“八·五”科技攻关项目“０．８～１微米分步重复投影光刻机”，于１９９６年１月通过了国家验收，１９９６年１１月至１９９７年４月在北京微电子中心按“０．８微米ＣＭＯＳ全套工艺”进行工艺考核...     

合同能源管理在我国供热空调系统中的应用前景分析

针对我国的能源形势,分析了供热空调系统的节能潜力,介绍了具有很好发展前景的合同能源管理概念、方法和步骤,以及在我国实施过程中出现的问题及对策.以实际空调和供热工程的案例对合同能源管理的效益进行了分析,结果表明,合同能源管理是一种业主和合同能源管理公司双赢的模式,在我国供热和空调行业有广阔的应用前景.     

EMC in the new millennium

EMC is an important part of the ever-changing world in which we now find ourselves. Society is increasingly dependent on radio, telecommunications and electronic products, but their use is only possible if the necessary EMC criteria are met. However the criteria of the last century will not necessarily be those required for the one that we have just entered. EMC is no longer a backwater of engineering where we can afford to leave the problems to the “experts”; it is and area where every engineer needs to become involved. Undoubtedly EMC has made significant strides forward during the past decade, but further progress is necessary if we are to ensure that we continue to enjoy a relatively interference-free environment in the years to come. This paper looks at the six major challenges that need to be tackled if we are to be successful in controlling EMC in the new millennium     

What is the role of the accessibility of wood hydroxyl groups in controlling moisture content?

It has often been claimed that the equilibrium moisture content (EMC) of wood is controlled by the available hydroxyl group content and their accessibility, but this has not been proven. In the present study, the accessibility of the hydroxyl groups were analysed by deuterium exchange in a dynamic vapour sorption apparatus, and generally poor correlation with the EMC and hydroxyl group accessibility was found. Therefore, the role of the accessibility of wood hydroxyl groups in relation to exerting sole influence on the EMC is disputable. It is concluded that there has to be an additional mechanism to exercise control over the EMC in addition to hydroxyl group accessibility.     

Ocean-color optical property data derived from the Japanese Ocean Color and Temperature Scanner and the French Polarization and Directionality of the Earth's Reflectances: a comparison study

We describe our efforts to study and compare the ocean-color data derived from the Japanese Ocean Color and Temperature Scanner (OCTS) and the French Polarization and Directionality of the Earth's Reflectances (POLDER). OCTS and POLDER were both on board Japan's Sun-synchronous Advanced Earth Observing Satellite from August 1996 to June 1997, collecting approximately 10 months of global ocean-color data. This operation provided a unique opportunity for the development of methods and strategies for the merging of ocean-color data from multiple ocean-color sensors. We describe our approach to the development of consistent data-processing algorithms for both OCTS and POLDER and the use of a common in situ data set to calibrate vicariously the two sensors. Therefore the OCTS- and POLDER-measured radiances are bridged effectively through common in situ measurements. With this approach to the processing of data from two different sensors, the only differences in the derived products from OCTS and POLDER are the differences that are inherited from the instrument characteristics. Results show that there are no obvious bias differences between the OCTS- and POLDER-derived ocean-color products, whereas the differences due to noise, which stem from variations in sensor characteristics, are difficult to correct at the pixel level. The ocean-color data from OCTS and POLDER therefore can be compared and merged in the sense that there is no significant bias between two.     

On combination of the equivalent material concept and J‐integral criterion for ductile failure prediction of U‐notches subjected to tension

The aim of the present research is to check the capability of the equivalent material concept (EMC) combined with the J‐integral failure criterion, called EMC‐J criterion, in predicting the load‐carrying capacity (LCC) of U‐notched ductile aluminium plates subjected to tension by considering the 2 moderate and large‐scale yielding regimes. For this purpose, first, a set of experimental results on LCC of 2 groups of thin U‐notched rectangular plates made of Al 7075‐T6 and Al 6061‐T6 are gathered from the recent literature. Then, because the Al 7075‐T6 and Al 6061‐T6 plates have ductile behaviour, EMC is employed to avoid performing elastic‐plastic failure analysis for LCC predictions. Up to now, different failure models in the context of the linear‐elastic notch fracture mechanics have been successfully utilized in combination with EMC for ductile failure prediction of notched members. However, this is the first time in this research that J‐integral, as a well‐known brittle failure criterion, is linked to EMC for predicting LCC of the U‐notched rectangular aluminium plates. Finally, it is shown that EMC‐J criterion can predict well the experimental results of tensile LCC.     

Isotope 18O/16O ratio measurements of water vapor by use of the 950-nm wavelength region with cavity ring-down and photoacoustic spectroscopic techniques

Two optical methods, cavity ring-down spectroscopy and photoacoustic spectroscopy, are applied to the measurement of the isotope ratio 18O/16O in water-vapor samples with a Nd3+:YAG pumped-dye laser. The combination band of (2v1 + v3) in the 960-nm region of water molecules is investigated for two standard water samples, the Vienna Standard Mean Ocean Water and the Standard Light Antarctic Precipitation. The results demonstrate that the two methods have the potential of compact systems for in-situ measurements of H2O isotope ratio in the environment.