除冰液对道面混凝土的影响及保护剂防护效果

通过冻融和化学侵蚀试验，研究了NW-056A机场道面除冰液对道面水混混凝土耐久性的影响以及在道面除冰液环境下两种新型混凝土保护剂的防护效果。结果表明：①混凝土在道面除冰液中冻融后表面无明显剥落现象，相对动弹模损失率比在水中小很多，道面除冰液延缓了混凝土的冻融破坏：②混凝土在道面除冰液常温浸泡下表面无剥蚀现象，但强度比在水中降低很多，因此存在化学腐蚀．且主要表现为对混凝土内部结构的缓慢损伤；（④两种新型混凝土保护剂均对预防混凝土的冻融破坏以及除冰液环境下的腐蚀破坏起到一定作用，涂刷混凝土保护剂是提高混凝土道面耐久性的有效方法。     

机载蒸发循环系统动态仿真

从部件的数学模型出发,根据闭环系统各部件的耦合关系,建立了机载蒸发循环系统的动态数学模型。对充注R142b的机载蒸发循环系统进行了动态仿真,仿真数据与试验数据基本吻合,仿真方法可靠,可以作为机载蒸发循环系统优化及系统控制的依据。     

FINITE DIFFERENCE MODEL FOR SIMULATION OF DENSIFYING CARBON-CARBON COMPOSITES BY CHEMICAL VAPOR INFILTRATIONP ROCESSES

ＮｏｍｅｎｃｌａｔｕｒｅｓＡ０—ｃｏｅｆｉｃｉｅｎｔｏｆｔｈｅＡｒｈｅｎｉｕｓｅｑｕａｔｉｏｎＣ（ｎ）—ｈｙｄｒｏｃａｒｂｏｎｃｏｎｃｅｎｔｒａｔｉｏｎｉｎｕｎｉｔ（ｎ）（ｍｏｌ／ｃｍ３）Ｃ０—ｈｙｄｒｏｃａｒｂｏｎｃｏｎｃｅｎｔｒａｔｉｏｎａｔｅｘ...     

On initial steps of chemical prebiotic evolution: Triggering autocatalytic reaction of oligomerization

Searching for extraterrestrial life attracts more and more attention. However this searching hardly can be effective without sufficiently universal concept of life origin, which incidentally tackles a problem of origin of life on the Earth. A concept of initial stages of life origin is stated in the paper. The concept eliminates key difficulties in the problem of life origin, and allows experimental verification of it. According to the concept the predecessor of living beings has to be sufficiently simple to provide non-zero probability of self-assembling during short (in geological or cosmic scale) time. In addition the predecessor has to be capable of autocatalysis, and further complication (evolution). A possible scenario of initial stage of life origin, which can be realized both on other planets, and inside experimental facility is considered. In the scope of the scenario a theoretical model of multivariate oligomeric autocatalyst is presented. Results of computer simulation of two versions of oligomeric autocatalytic reactions are presented. It is shown that the contribution of monomer activation reaction is essential, and in some cases autocatalysis in polymerizing reaction can be achieved without catalyzing proper monomer binding reaction.     

Comets and Chemical Composition

It is commonly believed that comets are made of primordial material. As a consequence, they can reveal more information about the origin of our solar system. To interpret the coma composition measurements of comet Churyumov–Gerasimenko that will be collected by the Rosetta mission, models of the coma chemistry have to be constructed. However, programming the chemistry of a cometary coma is extremely complex due to the large number of species and reactions involved. Moreover, such a program needs to be very flexible as one may want to extend, change, or update the set of species, reactions, and reaction rates. Therefore, we developed software to manage a database of species and reactions and to generate code automatically to compute source/loss balances. This database includes the data from the UMIST database and the ion–molecule reactions collected by V.G. Anicich. To use all these databases together, a lot of practical problems need to be solved, but the result is an enormous source of information about chemical reactions that can be used in chemical models, not only for comets but also for other applications.     

用准稳态方法建立碳氢燃料点火燃烧的简化化学反应动力学模型

基于“准稳态”方法建立了一套碳氢燃料点火燃烧的化学反应动力学模型简化方法和相应的软件SPARCK,并从甲烷点火燃烧的GRI2.11详细基元反应动力学模型出发简化得出了包含16个组分12步总包反应形式的简化化学反应动力学模型,从庚烷点火燃烧的详细基元反应动力学模型出发简化得出了包含25个组分21步总包反应形式的简化化学反应动力学模型。通过其计算结果与CARM软件导出简化模型的计算结果和典型激波管试验结果的对比可以看出,本文简化得到的简化反应动力学模型能较为有效地再现详细基元反应模型的反应机理,简化模型的计算精度与CARM软件导出简化模型的计算精度相当。与详细基元反应动力学模型相比,简化模型有效地减少了反应组分,在工程计算中有比较好的应用前景。     

铸造碳纤维增强铝基复合材料

 用铸造法制备抗拉强度达800MPa的连续碳纤维增强铝基复合材料。将国产PAN 1碳纤维经SiC+Ni复合涂层处理后,以束状分布于铸模内,用调压铸造设备在0.75MPa的空气压力和4000Pa的真空度条件下,将铝合金液浸渗入铸模纤维内而获得C/Al复合材料。讨论了碳纤维复合涂层的作用和纤维的束状分布在浸渗动力学过程中的有利影响。     

RDX－CMDB推进剂铅－铜－炭催化燃速模型

分析了ＲＤＸ在平台催化中的作用，认为ＲＤＸ对平台催化有正、负两方面的影响。据此提出了ＲＤＸ－ＣＭＤＢ推进剂平台催化燃速模型。导出的燃速公式能够定量地描述平台燃烧现象的各个阶段。在ＭＴＷ－１推进剂基础配方的应用表明，计算值与实测值之间的平均相对误差小于１０％。     

钨渗铜材料在真空高压开关上的应用

为适应高压真空开关抗熔焊、耐电蚀、高电导、低含气量等要求，对传统的生产工艺作了一系列改进，采用纯钨粉经模压成型、高温烧结，然后一次完成渗铜和覆铜。结果表明，钨骨架强度高，钢呈网状分布，基体组织细小均匀，气体含量低，覆铜层与钨铜基体结合紧密，从而满足了使用要求，降低了成本，获得了较好的经济效益。     

Deep Impact: A Large-Scale Active Experiment on a Cometary Nucleus

The Deep Impact mission will provide the first data on the interior of a cometary nucleus and a comparison of those data with data on the surface. Two spacecraft, an impactor and a flyby spacecraft, will arrive at comet 9P/Tempel 1 on 4 July 2005 to create and observe the formation and final properties of a large crater that is predicted to be approximately 30-m deep with the dimensions of a football stadium. The flyby and impactor instruments will yield images and near infrared spectra (1–5 μm) of the surface at unprecedented spatial resolutions both before and after the impact of a 350-kg spacecraft at 10.2 km/s. These data will provide unique information on the structure of the nucleus near the surface and its chemical composition. They will also used to interpret the evolutionary effects on remote sensing data and will indicate how those data can be used to better constrain conditions in the early solar system.