转向连接销热处理工艺研究

为避免某重型载货汽车前桥上的转向连接销(40CrH钢)产生淬火裂纹,同时满足金相组织要求,采用水溶性淬火介质(PAG类聚醚)进行了淬火工艺试验.结果表明,采用淬火温度为840℃、水溶性淬火溶液浓度为8％～10％及温度为20～50℃的新工艺进行淬火效果最佳,无淬火裂纹产生,累计生产的50万件转向连接销均未出现质量问题.     

Natural and anthropogenic hydrocarbons in the water column of the Ross Sea (Antarctica)

In the framework of the Italian Research Programme in Antarctica (PNRA) an oceanographic cruise was carried out between December 2000 and February 2001 in the Western Ross Sea. n-Alkanes and PAHs concentrations were analysed in sea-water samples collected at different depths at four sites (D, B, CA2, and CA). Vertical profiles of pressure, temperature, salinity and fluorescence were also performed in order to distinguish the water masses present in the sampling areas. n-Alkanes concentrations were consistent with those found in the same area during previous expeditions and showed higher values in the particulate due to the low temperatures. n-Alkanes profiles exhibited different features in the dissolved and particulate phases. The dissolved phase was characterised by a bimodal distribution with two maxima at C16 and C24 and prevalent compounds in the range C15–C32 whereas particulate was strongly dominated by long chain n-alkanes C23–C34 with C24 (Site B, CA and CA2) or C32 (Site B) as Cmax. CPI values and Pr/Ph ratios suggested a prevalent biogenic origin for aliphatic hydrocarbons. n-Alkanes vertical distributions were affected by the dynamic of the pack-ice melting and phytoplankton activity as well by the chemical–physical properties of water masses. Higher n-alkanes values were found in the High Salinity Shelf Waters (HSSW), lower n-alkanes values were found in the Antarctic Surface Waters (AASW) and Modified Circumpolar Deep Water (MCDW).The low PAHs concentration levels confirmed the still pristine character of the Antarctic environment. Neither particular trend in total PAHs concentrations along the water column and nor correlations with the most characteristic water masses of the investigated area of the Ross Sea were observed, except that total PAH higher concentrations were generally observed in correspondence of HSSW.     

SMS水动力学软件

简要介绍了水动力学软件SMS的基本功能,并用简单实例对其前后处理功能做了展示。     

Population dynamics of the red shrimp Aristeus antennatus in the Balearic Islands (western Mediterranean): Short spatio-temporal differences and influence of environmental factors

The red shrimp Aristeus antennatus is one of the target species of the bottom trawl fishery of the Balearic Islands. The objective of the present paper is to study the short spatial and temporal differences of this important economic resource between two different locations off Mallorca (Cabrera: CA; Sóller: SO), where a fleet mobility pattern has been detected, and to study the influence of environmental conditions on this species. Six simultaneous bottom-trawl and oceanographic surveys were carried out at these two locations in order to collect data from the demersal species, hydrography (temperature and salinity), trophic resources and sediment characteristics. The commercial fleet from both locations was monitored by monthly on-board sampling, log-books and daily landings obtained from sales slips. Additional data was obtained from other fishing surveys. Short spatial and temporal differences have been detected between both locations. The population at CA was more demographically homogeneous, while that at SO showed important variations, like high abundance of juveniles recruiting to fishing grounds in autumn–winter and high abundance of large females during summer. Several differences have also been found in the biology of the species between locations, such as males were more abundant in SO than in CA. Also, the reproductive period started sooner in SO than in CA, and the condition of pre-spawning females was better in SO. The percentage of total lipids in the hepatopancreas was minimal during the spawning period, showing their importance as a reserve of energy for the ovary ripening. Water masses could play an important role in these differences, the characteristics of water masses being more stable in CA than in SO. Red shrimp adult females seemed to be more correlated with the warmer and more saline Levantine Intermediate Waters, while juveniles (males and females) and adult males were more correlated with the colder Western Mediterranean Deep Waters, detected only in SO during autumn–winter. Two different hypothesis of mobility patterns for the species are discussed in relation to these observed differences.     

基于非线性渗流模型的管道型岩溶隧道突水机理研究北大核心CSCD

管道型岩溶突水是一个复杂的多场耦合的非线性渗流问题,致灾具有突发性。为揭示管道型岩溶突水灾害的发生机理,文章基于多物理场耦合作用机理,开展了不同溶腔水压、岩溶管道内不同填充介质、不同岩溶管道宽度及岩溶管道长度条件下的多场耦合分析。得到以下结论:(1)管道型岩溶破坏模式下发生的突水灾害,根据填充介质透水性能的异同而表现不同;(2)流体从富水溶腔中流出时流速较小,流经岩溶管道后流速逐渐增加,进入隧道后达到最大值;(3)影响突水过程的因素主要有:富水溶腔水压、岩溶管道或断层裂隙带内填充介质的种类、岩溶管道的宽度、隧道与水源的距离,其中,岩溶管道宽度及岩溶管道内填充介质类型对突水影响大于其他因素。     

Experimental analysis of exhaust gas after treatment system using water scrubbing in a single cylinder diesel engine for diesel and biofuel blends

A low-cost exhaust gas after treatment system called water-scrubbing is attempted in this paper. An emission treatment setup is fabricated, which is installed in the exhaust of the engine. This takes the exhaust gas and sprays water in the exhaust and passes it through the chamber containing silica gel. An attempt is made to investigate experimentally the performance and emission characteristics of a direct injection (DI) diesel engine, with and without water injection at the exhaust using diesel fuel (DF), diesel-Karanja oil blend (DKB) and diesel-Jatropha oil blend (DJB). The exhaust gas after treatment system helps to reduce NOx, CO and Particulate matter. The performance of the engine has also been monitored to determine whether the engine has any decrease in performance when the setup is used and it is found that there is no change in the engine performance.     

高压疏水双螺杆泵设计技术研究

用于高压疏水的泵一般选取往复泵,但往复泵结构复杂,零部件多,体积大,振动噪声不容易解决。因此开展了用于高压疏水的双螺杆泵开发设计,主要从螺杆型线、整体结构、加工工艺及表面处理等方面进行了研究。     

深水S型铺管托管架结构的非参数化敏感性分析

托管架是铺管作业的大型设备,其安全性对作业安全极为重要。针对托管架结构损伤实时监测这一目标,对深水作业状态的托管架结构进行整体和局部刚度校核、强度校核,并用设计波法校核了深海铺管作业的稳定性,在上述所得托管架结构的基本力学数据基础上,对托管架的构件进行了整体变形、局部变形、整体应力分布、疲劳易发点应力水平、关键连接杆应力水平和主弦杆多杆交汇处应力水平的敏感性分析,找出了托管架结构的关键构件,作为实时监测的测量点,为结构损伤实时监测做出了至关重要的准备性工作。     

土工格栅加固膨胀岩渠坡的施工技术

介绍了土工格栅+开挖料回填加固膨胀岩渠坡的原理、施工技术。现场施工证实了土工格栅+开挖料回填处理加固膨胀岩渠坡在施工工艺上的可行性。由于处理措施充分利用了开挖出来的膨胀岩,减少了对环境的破坏,避免了资源的浪费,为膨胀岩开挖料的再利用提供了一条有效途径。     

南水北调西线隧洞独头通风14km方案研究

规划中的南水北调西线工程地处海拔高程3 000 m以上的青藏高原,高原高寒缺氧为主要气候特点。输水线路隧洞长244km,最长洞段73 km,TBM单工作面掘进长度达25 km,考虑布置通风竖井通风,独头通风距离将达到14 km,在国内外隧道工程中都是罕见的。对通风设备、通风系统进行研究,提出14 km独头通风解决方案,为西线工程提供参考。