Interstellar cloud material: contribution to planetary atmospheres

A statistical analysis of the properties of dense interstellar clouds indicates that the solar system has encountered at least a dozen clouds of sufficient density to cause planets to accumulate nonnegligible amounts of some isotopes. The effect is most pronounced for neon. This mechanism could be responsible for much of the neon in Earth's atmosphere. For Mars, the predicted amount of neon added by cloud encounters greatly exceeds the present abundance.     

Origin and evolution of outer solar system atmospheres

The atmospheres of bodies in the outer solar system are distinct in composition from those of the inner planets and provide a complementary set of clues to the origin of the solar system. This article reviews current understanding of the origin and evolution of these atmospheres on the basis of abundances of key molecular species. The systematic enrichment of methane and deuterated species from Jupiter to Neptune is consistent with formation models in which significant infall of icy and rocky planetesimals accompanies the formation of giant planets. The atmosphere of the Saturnian satellite Titan has been strongly modified by photochemistry and interaction with the surface over 4.5 billion years; the combined knowledge of this moon's bulk density and estimates of the composition of the surface and atmosphere provide some constraints on this body's formation. Neptune's satellite Triton is a poorly known object for which it is hoped that substantial information will be gleaned from the Voyager 2 encounter in August 1989. The mean density of the Pluto-Charon system is well known and suggests an origin in the rather water-poor solar nebula. The recent occultation of a star by Pluto provides evidence that carbon monoxide, in addition to methane, may be present in its atmosphere.     

Catalytic processes in the atmospheres of Earth and venus

Photochemical processes in planetary atmospheres are strongly influenced by catalytic effects of minor constituents. Catalytic cycles in the atmospheres of Earth and Venus are closely related. For example, chlorine oxides (CIOx) act as catalysts in the two atmospheres. On Earth, they serve to convert odd oxygen (atomic oxygen and ozone) to molecular oxygen. On Venus they have a similar effect, but in addition they accelerate the reactions of atomic and molecular oxygen with carbon monoxide. The latter process occurs by a unique combination of CIOx catalysis and sulfur dioxide photosensitization. The mechanism provides an explanation for the very low extent of carbon dioxide decomposition by sunlight in the Venus atmosphere.     

铁合金电炉中的液压传动技术

本文介绍了某厂１２５００千伏安锰硅合金电炉的电极把持器、电极压放、电极升降装置及其液压传动系统，并作了一些改进．     

柔性管道抗径向挤压能力数值模拟

柔性管道在安装过程中会受到张紧器等安装设备的夹持作用,夹持力过小会引起管道外护套层滑脱,夹持力过大则会导致管道的径向挤压破坏。为预测柔性管道抗径向挤压能力,建立了柔性管道完整截面的三维有限元模型。对管道承受外压的骨架层结构进行径向挤压模拟,发现骨架层结构在加载过程中逐渐演变为含有4个塑性铰的活动机构,且在垂直于挤压方向的结构区域发生屈服时,结构的抗压刚度瞬间下降。对柔性管道不同结构层结构的抗压能力进一步分析,发现骨架层承压占比仅为整个结构的39.01%,安装过程中的抗挤压能力分析若仅考虑骨架层则过于保守。研究成果可为柔性管道抗压能力的预测提供参考。     

Earth and Mars: evolution of atmospheres and surface temperatures

Solar evolution implies, for contemporary albedos and atmospheric composition, global mean temperatures below the freezing point of seawater less than 2.3 aeons ago, contrary to geologic and paleontological evidence. Ammonia mixing ratios of the order of a few parts per million in the middle Precambrian atmosphere resolve this and other problems. Possible temperature evolutionary tracks for Earth and Mars are described. A runaway greenhouse efect will occur on Earth about 4.5 aeons from now, when clement conditions will prevail on Mars.     

水力旋流器在多泥沙河流中应用的研究

利用水力旋流器，对水力机械的润滑、轴封用水进行净化，降低泥沙含量，使之达到技术供水标准。本文研究和分析了水力旋流器的结构、各部构件尺寸与净化泥沙性能的关系；指明了水经过旋流器的压力降的确定，使之既满足泥沙沉降的要求，又要保证供水系统的所需的压力值。     

Using Augerhole Method to Determine the Hydraulic COnductivity of Soil

A kind of international rapid field measurement methods of hydraulic conductivity and it‘s applications in Sanjiang plain have been introduced in the paper.     

The effects of enriched carbon dioxide atmospheres on plant--insect herbivore interactions

Little is known about the effects of enriched CO(2) atmospheres, which may exist in the next century, on natural plant-insect herbivore interactions. Larvae of a specialist insect herbivore, Junonia coenia (Lepidoptera: Nymphalidae), were reared on one of its host plants, Plantago lanceolata (Plantaginaceae), grown in either current low (350 parts per million) or high (700 ppm) CO(2) environments. Those larvae raised on high-CO(2) foliage grew more slowly and experienced greater mortality, especially in early instars, than those raised on low-CO(2) foliage. Poor larval performance on high-CO(2) foliage was probably due to the reduced foliar water and nitrogen concentrations of those plants and not to changes in the concentration of the defensive compounds, iridoid glycosides. Adult pupal weight and female fecundity were not affected by the CO(2) environment of the host plant. These results indicate that interactions between plants and herbivorous insects will be modified under the predicted CO(2) conditions of the 21st century.     

CO2气调技术防治害虫研究进展与展望

综述了CO2气调技术防治害虫的主要影响因素CO2气体浓度、处理时间、温度、湿度和压强等及在仓储和植物检疫处理方面的研究进展和商业应用成果.指出在一定温度等环境条件下,CO2气调技术可作为有效防治密闭环境中害虫的溴甲烷等熏蒸剂的替代品或补充方法,在粮食、水果和蔬菜仓储、害虫防治和检疫处理等领域具有很好的应用推广价值.     

管道水力摩阻系数的计算

介绍了计算机水力摩阻系数λ的通用公式,在分析现有计算摩阻系数公式的基础上,借助于专门的过渡函数,求出了新的通用式。     

Using Inversed Augerhole Method to Determine the Hydraulic Conductivity of Soil

A kind of international rapid field measurement methods of hydraulic conductivity and it‘s applications in Sanjiang Plain have been introduced in the paper.     

转基因杂交棉新品种荆杂棉166的选育与应用

荆杂棉166是荆州市农业科学院用荆B6作母本、荆W101作父本杂交配组而成转基因杂交抗虫棉花新品种，该品种具有生长势强、丰产稳产性好、纤维品质优、抗病性强、抗棉铃虫等特点。2008年2月通过湖北省农作物品种审定委员会审定，适合在湖北棉区种植。     

欧文氏菌T85—166果胶酶基因克隆与序列分析

根据果胶酶Pel基因在欧文氏菌基因组上的分布特点,通过合理设计引物,从欧文氏菌株T85-166克隆出3个果胶酶Pel基因(Pel-1、Pel-2和Pel-3),它们分别编码372、373和374个氨基酸.序列分析表明,Pel-1前105及后100个氨基酸序列与Pel-2完全相同,但与Pel-3有较大差异,而中间170个左右的氨基酸序列与Pel-3则高度相似.初步构建了3个Pel基因的工程菌.     

不同沙土配比根系层导水特性研究

采用定水头法研究了不同沙土配比根系层的渗透特性,探讨沙土组成比例对土壤渗透特性的影响规律,并结合运动场草坪根系层饱和导水率推荐标准及处理间的差异显著性,对各处理土壤的渗透性进行综合分析。结果表明:随着含沙量增加,无论是原状土还是压实的扰动土,土壤饱和导水率均增加,增加趋势先缓后快,m(沙)∶m(土)=7∶3时(沙粒含量80%)增幅明显,与沙粒含量拟合均呈显著的指数函数关系;土壤稳定入渗率在草坪成坪前和成坪2个月后的变化趋势与室内测定饱和导水率基本一致,呈极显著的线性关系;按照处理间导水率的差异显著性,11个处理的饱和导水率基本可分为3类,即m(沙)∶m(土)3∶7(沙粒含量60%)、m(沙)∶m(土)为3∶7～7∶3(沙粒含量60%～80%)、m(沙)∶m(土)7∶3(沙粒含量80%)。      

非充填复垦土壤饱和导水率预报的岭回归模型

运用统计软件SAS9．0,运用岭回归技术,对非充填复垦土壤的饱和导水率与土壤紧实度、土壤有机质含量、非毛管孔隙度、毛管孔隙度、容重、水稳性团聚体含量间的关系作了详细研究,并建立了饱和导水率的岭回归预测模型。结果表明,土壤饱和导水率与容重、紧实度、毛管孔隙度、非毛管孔隙度、有机质含量、水稳性团聚体含量之间存在着严重的多重共线性问题,各因子对饱和导水率的作用依次为非毛管孔隙度〉紧实度〉容重〉有机质含量〉毛管孔隙度〉水稳性团聚体含量。该模型对研究充填复垦土壤的饱和导水率具有重要意义。     

汽车液压转向伺服系统

本文用液压系统动态仿真的基础理论，对汽车液压转向伺服系统的稳定性和瞬态响应进行了分析，为今后系统设计提供了可靠的方案．