球内凝固过程的近似解分析

对球内凝固相变过程作了较为系统和全面的理论分析 ,建立了能够揭示在第三类边界条件下球体内相变传热过程物理机制的数学模型 ,用Lighthill奇异摄动法给出了球体内对称凝固问题的近似分析解 ,并以Ba(OH) 2 ·8H2 O为相变材料 ,得到了相变界面、相变介质温度随时间和热流密度随相变位置的变化规律 ,以及球囊半径和对流换热系数对凝固过程的影响。得到结论 :对一般工程背景 ,球囊半径为 1 .5～ 2 .0cm ,h <1 0 0 0W /(m2 ·K)较为合适 ,从而为以球为相变贮能单元的贮能装置的优化设计提供了一定的理论参考。     

ZnO导电陶瓷的制备及电性能研究

采用注浆成型法制得ZnO导电陶瓷 ,通过添加Al2 O3、Cr2 O3、Fe2 O3、La2 O3,探讨了各添加剂对ZnO陶瓷电性能的影响。结果表明 ,聚丙烯酸胺 (PMMA)是ZnO粉体良好的分散剂 ,其质量分数在 0 3%时可得到低粘度、高固含量的ZnO悬浮体。各种氧化物添加剂的添加量对ZnO陶瓷的室温电阻率及电阻温度特性具有较大的影响。随着Al2 O3添加量的增加 ,ZnO陶瓷体的电阻率先略微减小然后增大 ;添加Cr2 O3与添加Al2 O3的效果相反 ;随着Fe2 O3、La2 O3添加量的增加 ,ZnO陶瓷体的电阻率增大。添加Al2 O3、Cr2 O3、Fe2 O3、La2O3的ZnO陶瓷呈现负电阻温度特性。     

Normalizing Behavior of Unsaturated Granular Pavement Materials

One of the important components of a flexible pavement structure is granular material layers. Unsaturated granular pavement materials (UGPMs) in these layers influence stresses and strains throughout the pavement structure, and have a large effect on asphalt concrete fatigue and pavement rutting (two of the primary failure mechanisms for flexible pavements). The behavior of UGPMs is dependent on water content, but this effect has been traditionally difficult to quantify using either empirical or mechanistic methods. This paper presents a practical mechanistic framework for determining the behavior of UGPMs within the range of water contents, densities, and stress states likely to be encountered under field conditions. Both soil suction and generated pore pressures are determined and compared to confinement under typical field loading conditions. The framework utilizes a simple soil suction model that has three density-independent parameters, and can be determined using conventional triaxial equipment that is available in many pavement engineering laboratories.     

屏蔽泵石墨轴承材料的强度和耐磨性研究

对屏蔽泵的石墨轴承材料的强度、磨损性和摩擦系数进行了实验研究。在DWD-3020电子万能试验机上对普通石墨和浸润树脂石墨材料的弹性模量进行了测定，同时确定了材料的拉伸和压缩强度极限。在Falex摩擦磨损机上对材料进行了磨损试验，得到了转速和载荷对这两种材料磨损的影响，并利用CSM950扫描电子显微镜对其摩擦表面作了形貌分析。     

论刑事侦查中的律师在场权

刑事侦查中讯问犯罪嫌疑人的不公开性、稳秘性 ,是导致刑讯逼供等侵犯公民人身权的主要原因 ,也影响了司法公正。本文要求了在刑事侦查中赋予律师以在场权 ,这是解决这一问题的关键性措施 ,也是实现刑事司法公正的必然要求。     

Shut-cut nitrification characteristics of aerobic granule in a sequencing batch airlift reactor at low temperature

To investigate the shut-cut nitrification characteristics of aerobic granule,an aerobic granular sequencing batch airlift reactor(AG-SBAR) was carried out with mixed carbon sources of sodium acetate and glucose at 10±1 ℃.Results indicated that ammonia oxidizing bacteria was accumulated inside the aerobic granules and the reactor performed stably with shut-cut nitrification for a long term at low temperature.During the stable operation period,the effluent ammonia nitrogen concentration was maintained at 13.6 mg/L without nitrate and nitrite when the COD/N ratio was 20:1.However,the effluent concentration of ammonia nitrogen was below 0.5 mg/L with effluent nitrosation ratio of 96.7% on average when the COD/N ratio was reduced to 15:1 and 10:1.And the effluent phosphorus concentration was less than 0.4 mg/L during the stable period with the sludge retention time of 30 d.The phosphorus removal efficiency was not strongly influenced by the adjustment of COD/N ratio in this experiment.The removal efficiencies for COD,NH4+-N and PO43--P were 91.3%-94.6%,97.9%-99.7% and 97.1%-99.5%,respectively.     

土壤氡测量在呼斯梁—柴登壕地区砂岩型铀矿勘查中的应用

通过呼斯梁―柴登壕地区土壤氡活度浓度测量数据的处理,划分出土壤氡活度浓度异常范围,圈定了测区内重点成矿预测区土壤氡活度浓度异常分布范围:盐路渠和巴定壕附近。证明区域土壤氡活度浓度测量可实现盆地砂岩型铀矿快速评价的目的。     

添加ZrO2对铜基摩擦材料摩擦磨损性能的影响

采用粉末冶金方法制备了高速列车用铜基摩擦材料,研究了添加ZrO2的量对材料的摩擦因数、磨损量的影响规律。结果表明:在添加ZrO2的材料中,含5%(质量分数,下同)ZrO2的材料摩擦因数较高,磨损量也较大;添加8%ZrO2的材料在高速下的摩擦因数较高,磨损率较小且变化平稳。材料的磨损在较低的速度下以粘着磨损为主;随着速度的上升,磨损也逐渐变成以剥层脱落和氧化磨损的混合机制为主。     

60Si2MnA弹簧钢柔性化工艺控制的试验研究

采用光学、电子显微技术和力学分析等方法,结合热模拟试验和现场工业试验,研究了高速线材斯太尔摩控冷工艺生产高强度优质60Si2MnA弹簧钢的工艺参数与显微组织和力学性能之间的关系。研究表明,该弹簧钢盘条最终组织为珠光体加少量铁索体,随着相变冷速的升高,在铁素体含量变少及晶粒细化的同时珠光体球团分布更加弥散均匀,珠光体片层间距减小;不同强度级别的高强度60Si2MnA弹簧钢的延伸率几乎相当,断面收缩率相差0．5％,抗拉强度相差约200MPa,综合力学性能优良。     

快电子对快离子损失诊断测量的影响

基于闪烁体原理的快离子损失探针(Fast Ion Loss Detector,FILD),可以同时测量损失快离子的能量和pitch-angle的值,是核聚变装置中对高能粒子诊断的重要方式。根据先进实验超导托卡马克(Experimental Advanced Superconducting Tokamak,EAST)的发展需求,为了更好地对损失快离子行为进行研究,设计并安装了快离子损失诊断,且探测到在中性束加热条件下产生的损失快离子。同时,探测到在放电中产生的逃逸电子,以及低杂波注入时快电子产生X射线对快离子损失背景信号的影响。并且在H-mode放电时边界扰动也对快离子损失信号产生影响,这些探测到的现象都为不断升级损失诊断系统提供依据。