低收缩感光性高分子材料的研究

报道了非收缩单体SOC_7的光引发正离子共聚合,证明少量SOC_7加到ERL—4221体系中,可抑制固化收缩,而材料性能没有明显降低。并证明是共聚物结构。     

Surface damages and tool wear mode in end milling of hastelloy‐C276 under dry and wet conditions

Hastelloy‐C276 is a nickel based superalloy that is widely used in chemical, petro‐chemical, environmental and nuclear industries due to its outstanding performance in a wide range of corrosive mediums. The superior properties of nickel based superalloys impair their machinability which increases the difficulty in obtaining a good surface finish. Because most of the components' failures are initiated from surface defects, several researchers have been concerned about surface integrity in machining aerospace superalloys particularly Inconel‐718. Due to the lack of studies done on machining corrosion‐resistant superalloys, this study aims to investigate surface damages and tool wear modes in milling Hastelloy‐C276 under dry and wet conditions. The absence of cooling and lubricating actions in dry machining resulted in the formation of craters, severe plastic deformation, voids, debris re‐deposition and materials drag. The breakage of the nucleated carbide phases resulted in the formation of nucleated cavities on the machined surface in both wet and dry machining. Adhesive tool wear was less in dry machining due to the formation of oxide layers on tool faces which suppressed the formation of built‐up edges due to the weak adhesion properties of oxide compounds which resulted in less surface roughness at v_c = 50 m/min. On the other hand, the higher temperature and friction in dry machining resulted in severer tool coating delamination.     

工程承包中索赔风险因素的探讨

分析工程承包中索赔风险因素的特点,讨论有关索赔风险因素的成因。     

AGS结构的损伤定位仿真

为了检测先进复合材料格栅结构(AG S)的损伤所在位置,提出了通过计算结构在损伤前、后模态曲率差的方法,来进行计算和分析。建立了格栅结构在有约束条件下的有限元模型,通过AN SY S中的模态分析得到模态振型位移值,计算了结构损伤前、后的模态曲率差,通过这一指标对结构的损伤进行辨识,并分析了采用多阶模态的计算效果。结果表明,通过第1阶模态振型模态曲率差的计算,可对单损伤状况做出有效的检测;对于多损伤工况,需使用前3阶模态的曲率差进行分析,才能有效检测损伤的位置。     

寒区隧道衬砌结构冻胀破坏分析及防治措施

分析了寒区隧道冻害形成的原因,认为围岩的冻融循环是造成隧道衬砌失稳破坏的基本因素,对寒区隧道冻胀形成机理研究及隧道设计有一定的参考价值,并总结了国内外寒区隧道冻胀破坏的防治措施,以减少寒区隧道的冻胀破坏。     

3D打印用光敏树脂材料研究进展

主要介绍了3D打印用光敏树脂的研究进展,包括为提高打印件性能而进行的光敏树脂的改性的研究现状,以及光敏树脂的电学、热学、生物医药等方面的功能化研究,最后对3D打印光敏树脂的发展做出总结及展望。     

Alteration of ADP-ribosylation in aging rat brain astrocytes

DNA damage and the enzyme poly (ADP-ribose) polymerase (PARP) associated with the pathogenesisof numerous age-related neurodegenerative disorders. Astrocytes play crucial roles in both support metabolicfunctions and cell viability of the brain. PARP regulates DNA damage and repair in the brain cells. In this study PARPactivity and DNA strand break were investigated in the astrocytes isolated from young and aged rat brain. Three and30-month-old rats were killed by decapitation and brains were removed onto an ice cooled glass plate. Astrocytes wereisolated by sucrose density gradient centrifugation and glutamine synthetase (GS) served as a marker of the astrocyteslineage. The specific activity of PARP was assayed in permeabilized cells by measuring the incorporation of the ADPribose moiety of [3H]NAD into the nuclear acceptor proteins. The rate of DNA strand breaks was determined usinga fluorescent dye and monitored spectrofluorimetry. An increase (about 75%) in the PARP activity was observed inthe whole homogenates of aged rats, whereas this rise was more pronounced (about 360%) when the reaction wasmeasured in the purified astrocyte preparations. The amount of DNA strand breaks was also higher in the astrocytesisolated from the aged brain as compared to that of young levels. The close relationship between the level of DNAstrand breaks and PARP activity in the astrocytes suggest that these cells are susceptible to the metabolic alterations inaging. It is concluded that the astrocytes PARP might be considered as a therapeutic target for combating age relatedneurodegenerative disorders.     

紫外吸收剂UV326的合成

介绍了国内需求的新型紫外吸收剂ＵＶ３２６的开发研制工作。在合成过程中采用重氮化均相反应和三步还原法的新技术,达到了总得率９０％以上和质量符合感光材料指标的效果,产品可以应用于感光工业。     

Visual stress, its treatment with spectral filters, and its relationship to visually induced motion sickness

We review the concept of visual stress and its relation to neurological disease. Visual stress can occur from the observation of images with unnatural spatial structure and an excess of contrast energy at spatial frequencies to which the visual system is generally most sensitive. Visual stress can often be reduced using spectral filters, provided the colour is selected with precision to suit each individual. The use of such filters and their effects on reading speed are reviewed. The filters have been shown to benefit patients with a variety of neurological conditions other than reading difficulty, all associated with an increased risk of seizures.