实施施工阶段建设监理的全过程管理

为使工程建设监理纳入规范化和程序化的管理，通过工程建设监理实践，我们归纳出了监理工作中的几点具体作法，可供从事工程建设监理方面的有关人员参考。     

纯铜动态再结晶的Monte Carlo法模拟

本文建立了一种基于能量判据的确定动态再结晶各个阶段临界应变的方法，并基于此种方法Monte Carlo(MC)法进行了纯铜动态再结晶的二维模拟，定量计算了变形引起的存储能与变形之间的关系，计算出了发生动态再结晶的临界应变。模拟结果表明，采用MC法可以揭示动态再结晶的形核生长过程与应变历史之间的关系。结合本文所建立的基于能量判据的确定动态再结晶各个阶段临界应变的方法，可以预测开始发生动态再结晶的临界变形条件。     

Stable Synthetic Bacteriochlorins for Photodynamic Therapy: Role of Dicyano Peripheral Groups,Central Metal Substitution (2H,Zn, Pd), and Cremophor EL Delivery

A series of four stable synthetic bacteriochlorins was tested in vitro in HeLa cells for their potential in photodynamic therapy (PDT). The parent bacteriochlorin (BC), dicyano derivative (NC)₂BC and corresponding zinc chelate (NC)₂BC–Zn and palladium chelate (NC)₂BC–Pd were studied. Direct dilution of a solution of bacteriochlorin in an organic solvent (N,N‐dimethylacetamide) into serum‐containing medium was compared with the dilution of bacteriochlorin in Cremophor EL (CrEL; polyoxyethylene glycerol triricinoleate) micelles into the same medium. CrEL generally reduced aggregation (as indicated by absorption and fluorescence) and increased activity up to tenfold (depending on bacteriochlorin), although it decreased cellular uptake. The order of PDT activity against HeLa human cancer cells after 24 h incubation and illumination with 10 J cm^?2 of near‐infrared (NIR) light is (NC)₂BC–Pd (LD₅₀=25 nM ) > (NC)₂BC > (NC)₂BC–Zn ≈ BC. Subcellular localization was determined to be in the endoplasmic reticulum, mitochondria and lysosomes, depending on the bacteriochlorin. (NC)₂BC–Pd showed PDT‐mediated damage to mitochondria and lysosomes, and the greatest production of hydroxyl radicals as determined using a hydroxyphenylfluorescein probe. The incorporation of cyano substituents provides an excellent motif for the enhancement of the photoactivity and photostability of bacteriochlorins as PDT photosensitizers.     

Characterization,Mechanism and Control Measures of V Segregation in Continuous Casting Billet of C-Mn Steel

Metallurgical and Materials Transactions B - To eliminate V segregation, which significantly deteriorates the homogeneity of continuous casting steel billets, V segregation in the C-Mn steel billet...     

回收弛放气中丙烯丙烷的技术及应用

在弛放气回收中试的基础上,进行了弛放气回收装置的工业化设计,装置弛放气设计处理能力为6.8kt/a,回收丙烯和丙烷5.5kt/a,年操作时数为8000h。该技术采用"吸收—精馏—再精馏"工艺路线,即吸收剂吸收弛放气中的丙烯、丙烷和丁醛,含丙烯、丙烷的吸收液经过精馏分离得到丙烯、丙烷的混合组分,再经过常规精馏分离得到丙烯和丙烷产品。吸收剂经提纯后可循环使用。在吸收丙烯、丙烷的同时,混合丁醛也被吸收,与丁醇分离后可作为产品抽出。应用该技术,丙烯、丙烷收率大于90%,产品丙烯纯度大于96%,丙烷纯度大于99%。该工艺技术为自有技术,其设备全部国产化。吸收塔、精馏塔和脱重塔采用天津大学开发的高效填料,精馏塔采用格里奇公司的高效塔盘,有效保证分离效果。全部设备和材料均可在国内生产制造,工程费用比较低。     

热处理工艺对含Nb焊缝金属组织与力学性能的影响

采用含Nb及不含Nb两种焊丝对高速列车转向架用S355J2G3钢板进行焊接,分析了焊态下接头各区域的性能差别,研究了合金元素Nb和焊后热处理制度对焊缝金属组织和性能的影响.结果表明:焊缝金属的韧性是焊接接头性能的薄弱环节.焊态下Nb的加入提高了焊缝金属的强度,但对塑性和韧性无明显影响.经去应力退火后,不含Nb焊缝金属的强度降低,延伸率和冲击功升高,而含Nb焊缝金属的强度升高,延伸率和冲击功降低,退火后含Nb焊缝金属中NbC颗粒析出是影响焊缝金属组织和性能的主要因素.在焊后正火处理条件下,随着正火温度的升高,不含Nb焊缝金属的组织和性能均无明显变化,而含Nb焊缝金属的强度明显升高,延伸率和冲击功显著降低.严格控制正火温度是含Nb焊缝金属获得高强韧性的关键.含Nb焊缝中魏氏组织的含量随正火温度的升高而明显增多.电镜观察表明,经920℃正火处理后,焊缝中的NbC颗粒尺寸大于退火态焊缝金属中的NbC相,而在1200℃正火处理后NbC颗粒溶解消失.     

U-6%Nb二元合金凝固过程中显微组织与显微偏析的模拟

提出一个改进的计算固相分数的模型,利用该模型及元胞自动机方法根据相图计算将固/液界面区域内固相分数表示为一个一元二次方程,不需假设界面的位置和形状.对U-6%Nb(质量分数)二元合金的凝固组织和显微偏析的模拟结果表明:初始形核部位Nb浓度最高,随着凝固的进行,该部位Nb浓度不断下降;凝固后期晶界区贫Nb,Nb浓度最低可达3%以下.     

苯酚氧化反应中溶剂选择及催化剂再生方法的研究

考察了水作溶剂对苯酚转化率及产品选择性的影响，并且对催化剂的再生方法进行了改进。研究发现，水及丙酮分别作溶剂时，通过控制反应参数，苯酚转化率可达到相近的水平；水作溶剂时，通过调整反应温度、水量、Ｈ２Ｏ２用量及其加入方式可以得到最大的苯酚转化率及Ｈ２Ｏ２利用率；高温水处理积炭催化剂的方法，可以减少催化剂的焙烧次数，简化原有的再生工艺。     

The 3-dimensional morphology of dendrite during equiaxed solidification of an Al-5 wt.% Cu alloy

In a sample quenched during equiaxed solidification of an Al-5 wt.% Cu alloy, the multi-scales 3-dimensional morphology of equiaxed dendrite was observed. The slim primary stem and secondary branches constitute the frame of dendrite, and rows of dense tertiary branches further divide the 3-dimensional space. In the divided space, the quartic branches grow further. The dendritic branches,which are perpendicular to each other, can change their growth directions and coalesce into a whole. In the tertiary branches and quartic branches, the formation of double branch structures is induced by competitive growth. The branch that wins in the competitive growth will produce a cabbage-like structure by wrapping the failed branches. In addition, the side branch can also wrap the original parent branch to produce cabbage-like structures. Depending on the historical growth direction, the dendritic arms can form vein-like and spicate structures, and the shapes of single dendritic arm may be the cylinder, plate and trapezoid platform. According to the compositions and etching morphology, the single dendritic arm in the final solidification structures should coalesce from a fine porous structure. The porous structures at different length-scales are principally induced by the preferential growth. Based on 3-dimensional morphology of equiaxed dendrite, a new research object for the investigation of microsegregation was suggested.     

枝晶凝固过程中的溶质浓度分布模拟

采用元胞自动机方法(cellular automation)对单个枝晶凝固过程中的显微偏析和枝晶形貌进行了模拟，在模拟的过程中，对固相和液相中的溶质传输分别进行了计算，同时考虑到凝固过程中同相分数的变化对溶质传输的影响与文献中通常采用的浓度势方法的计算结果进行对比，模拟结果显示本文使用的计算方法模拟显微偏析过程中波动小、结果更为稳定。