路堑边坡施工过程中后缘变形演化分析

在路堑边坡施工过程中,研究边坡后缘的变形趋势可以较早地提供整个边坡的变形的信息,对整个施工过程有实际的工程意义。基于数值模拟和现场监测结果,以漳州招银疏港高速公路A3标边坡(ZK14+165)为例来探索在施工过程中路堑边坡上缘的变形演化过程。结果表明:1)除了新开挖平台由于卸荷引起的变形以外,边坡上缘是产生变形的主要区域;2)随着开挖施工的进行,上缘变形越来越大,靠近开挖面处最大;3)变形发生在坡顶以上10m左右的范围内(针对此开挖高度为38.8m的路堑边坡),变形区域由上缘坡面到开挖面近似螺旋曲线的形状。     

消除应力回火对30CrMnSiNi2A真空电子束焊接头组织和力学性能的影响

针对30CrMnSiNi2A超高强度钢结构件真空电子束焊后消除应力回火工艺,开展了重复回火对锁底焊接接头最终热处理状态的组织与力学性能影响研究。试验结果表明,焊接零件分别经过一次、三次消除应力回火,其最终态拉伸性能与直接最终热处理30CrMnSiNi2A原材料相比有少量提升,同时焊缝的拉伸性能略高于母材;原材料、一次消除应力焊件、三次消除应力回火焊件终态显微组织均为板条状马氏体,除组织均匀性和马氏体形貌略微变化外,无显著的组织及成分差异;相比于母材的疲劳极限,一次消除应力回火接头疲劳极限降低了11%,三次消除应力回火接头疲劳极限降低了18%。创新点：(1)掌握了消除应力回火对接头拉伸性能和疲劳性能的影响规律。(2)结合微观组织分析,对影响机理进行了研究。     

中国原子能科学研究院紧凑型强流质子回旋加速器剥离引出技术研究

中国原子能科学研究院(CIAE)在20世纪90年代建造了一台30 MeV紧凑型强流质子回旋加速器后,经过近30年的发展,先后自主研发成功了基于剥离引出技术的能量为10 MeV、14 MeV、100 MeV、硼中子俘获治疗用14 MeV/1 mA等系列能量的紧凑型强流质子回旋加速器。建成的100 MeV紧凑型强流质子回旋加速器(CYCIAE-100),是目前国际上能量较高的一台紧凑型强流质子回旋加速器,最高流强达到520 μA,束流功率达到52 kW。建成的硼中子俘获治疗用的质子回旋加速器,也是我国首次自主研发成功的引出质子束流强达到mA量级的强流质子回旋加速器。在系列能量的紧凑型强流质子回旋加速器研发过程中,CIAE对剥离引出后的束流色散效应、剥离膜与束流夹角对引出后的束流品质的影响、单圈剥离引出技术等紧凑型强流质子回旋加速器剥离引出技术等方面展开了研究,且自主开发出了剥离引出计算程序,为紧凑型强流质子回旋加速器的应用作出了贡献。     

低本底反康普顿高纯锗γ谱仪

本文介绍的谱仪采用铅-石蜡-铅为主的复合物质屏蔽。HPGe探测器对~(60)Co的1332keV γ射线的相对效率为25％,能量分辨率好于1.75keV。在阱型反符合屏蔽下,系统对放在HPGe端面的~(137)Cs点状薄膜源的峰康比可达800:1;测量时间1000min,置信度95％时,对~(137)Cs点源探测灵敏度好于5.6mBq;谱议在100—2000keV能区内的积分本底好于8.7±0.1次/min,与无反符合屏蔽时相比,压缩倍数为6.6。     

DN2机车用喷油嘴的有限元数值分析

本文通过对DN_2机车用喷油嘴针阀体的有限元数值分析,得出了针阀体在机械负荷、液力负荷和热负荷作用下的变形和应力分布的定量值.为喷油嘴设计研究、生产使用、提高喷油嘴工作可靠性提供了依据.     

Influence of Barium Incorporation on the Electrochemical Performance of Ln0.58Sr0.4Fe0.8Co0.2O3–δ (Ln=La,Pr, Sm) Perovskites for Oxygen Activation at Intermediate Temperatures

Highly active perovskite‐based electrodes were obtained through partial substitution of lanthanides (La, Pr and Sm) by barium in the Ln_0.58Sr_0.4Fe_0.8Co_0.2O₃ system. These compositions were obtained as single phase crystalline compounds through a sol–gel synthetic route and tested by electrochemical impedance spectroscopy (EIS) as symmetrical cells on GDC‐electrolyte samples in the temperature range 450–650 °C. Cooperative effects arose through the incorporation of a large divalent active cation (Ba⁺²) in the perovskite lattice of lanthanide‐based strontium ferrites‐cobaltites. Reduction in the electrode polarisation resistance with respect to non‐substituted compositions is obtained irrespective of the amount of barium substitution and lanthanide nature. Barium addition also reduces the activation energy of these compositions, indicating changes in the oxygen activation processes. The specific effect of the barium incorporation on the electrode performance was dependent on the nature of the partially substituted lanthanide. Lanthanum–barium‐based compositions exhibited the lowest electrode polarisation resistance when the amount of the replaced barium was increased up to 50% molar. On the other hand, for praseodymium‐ or samarium–barium‐based compositions, the minimum in electrode polarisation resistance was achieved at barium substitutions close to 25% molar. The study of the effect of oxygen partial pressure on EIS data allowed in improving the understanding of the processes governing the electrode operation.     

基于I-DEAS的漏斗车底架组对夹具机构仿真研究

利用I-DEAS软件对铁路漏斗车底架组对夹具进行了三维设计和机构仿真,并验证组对夹具中夹紧装置设计的合理性。     

Enzyme-catalyzed polymerization and degradation of copolymers prepared from ?-caprolactone and poly(ethylene glycol)

Copolymerizations of ?-caprolactone (CL) with monohydroxyl or dihydroxyl poly(ethylene glycol) (PEG) were successfully performed using Novozyme-435 (immobilized lipase B from Candida antartica) as catalyst. Diblock and triblock copolymers with different compositions were characterized by ¹H NMR, GPC, DSC and X-ray diffraction. The enzymatic copolymerization carried out in toluene presented higher reaction rate and yield than that in bulk. Increasing the [CL]/[EO] feed ratio resulted in increases of molecular weight (M_n) of copolymers. Moreover, the compositions of triblock copolymers were closer to the monomer feed ratios than those of diblock copolymers. The resulting copolymers were all semicrystalline, the crystalline structure being of the PCL type. Solution cast films were allowed to degrade in a pH 7.0 phosphate buffer solution containing Pseudomonas lipase. Weight loss data showed that the introduction of PEG segments to the PCL main chain did not alter the enzymatic degradation of PCL significantly.     

Evidence for the amphiphilic structure of partially hydrogenolyzed poly(β-malic acid benzyl ester)

Summary Acidic copolymers of the poly(-hydroxy-acid) type containing -malic acid (hydrophilic) and -malic acid benzyl ester (hydrophobic) repeating units in various proportions are prepared by two differentes routes : — catalytic hydrogenolysis of the benzyl ester bonds of homopoly(-malic acid benzyl ester) and — chemical coupling of benzyl alcohol to poly(-malic acid). In attempts to account for the route-dependence of the physico-chemical properties of resulting copolymers, GPC in aqueous medium and measurements of the solubility of Yellow OB, a lipophilic dye, in aqueous solutions have been carried out. The results are discussed in regard to the sequence distributions of hydrophilic and hydrophobic repeating units.     

杭州人民大厦外墙整修处理

1工程概况 杭州人民大厦位于杭州市潮王路169号,1999年始建成投入使用.现场检查发现,四面墙体出现多处明显裂缝,雨天时雨水通过裂缝渗入室内,对整幢大厦的正常使用带来了负面影响.业主曾两次请施工单位做墙面裂缝防水处理,效果均不理想,最后业主邀请本单位对大厦外墙进行全面整修处理.