Characterization of surface grooves and scratches induced by friction of C/C composites at low and high temperatures

Friction experiments were conducted on C/C composites at low and high temperatures during braking with the use of a pin-on-disc tribometer. The surface grooves formed were investigated by an optical camera and a laser profilometer, while scratches were characterized by optical microscopy. Damages were correlated with tribological performances (friction and wear). It is shown that friction at low temperature leads to high friction coefficient and wear rate, and to surfaces strongly grooved and abraded. For friction experiments performed at high temperature, they lead to lower friction coefficient and wear, and the resulting surfaces are rather smooth and slightly grooved.     

Use of the area of main influence to fix a relevant boundary for mining damages in Germany

In 2010, the fracking discussion in Germany caused a number of changes in German law, which came into force in 2016.Especially the production of gas had to be regulated.With the legislation amendment, the Subsidence-Area Mining Regulation has been revised, too.The changes expand the compensation of mining damages, especially to the extraction with drilling from the surface and underground storage.Although the Subsidence-Area Mining Regulation has been revised, the area of main influence(subsidence of 10 cm)remains to determine a relevant boundary for mining damages.The determination and prediction of this boundary above caverns are presented in this paper.In addition, further elements of ground movements and their relevance to mine damages are analyzed.The usage of the area of main influence to fix a relevant boundary for mining damages does not correspond to the relevant elements of ground movements.A limit for differences in subsidence(tilt) or horizontal changes in length should be preferred to describe the relevance of mining damages on buildings.Furthermore, this paper outlines the meaning of using the area of main influence to fix a relevant boundary for mining damages.     

A novel negative photoinitiator-free photosensitive polyimide

A novel negative photoinitiator-free photosensitive polyimide (PFPS-PI) was synthesized through introducing the photosensitive 4,4-bis[(4-amino)thiophenyl] benzophenone (BATPB) into backbone chain and methyl acrylate group into side-chain of the polyimide, respectively. Photosensitive properties study revealed its good photolithographic properties, with a resolution about 5 μm and a sensitivity of 150 mJ/cm².     

Estimation of flood damage cost for Bangkok

Bangkok, located on a low lying alluvial deposit, is flooded almost every year by tide, river flow, and direct precipitation. Due to land subsidence caused by pumping of groundwater, the flooding is now more severe and more frequent than ever before. Various proposals have been presented to alleviate the flooding; however, selection of these alternatives would require cost-benefit analysis. The objective of this research is to estimate the cost of flood damage by first estimating the flood damage cost function in terms of depth and duration using the multiple regression analysis technique. In the case of Bangkok, results indicate that flood depth and flood duration are significant factors explaining flood damage in the residential and industrial areas. On the other hand, only flood depth was found to be an important factor affecting damage to the commercial and agricultural areas. The estimated cost functions served as a useful aid in the systematic computation of flood damage for 1983 which amounted to over 7.8 billion baht (US$ 1.00 baht 25.5).     

碱溶性光敏有机硅聚氨酯丙烯酸酯光固化膜的性能研究

设计合成了一种碱溶性光敏有机硅聚氨酯丙烯酸酯(Alkali-soluble polysiloxane urethane acrylate,APSUA),以期用于阻焊油墨.详细研究了体系组成对APSUA体系的耐水性、体积收缩、硬度、拉伸性能及耐热性能的影响.研究发现:含羟基活性单体会使体系吸水率上升;随着体系交联度增加,...     

Lipid changes during long-term storage of canned tuna (Thunnus alalunga)

 Lipid damage during prolonged storage of canned fish was studied. Albacore tuna was processed under two sterilization conditions (115°C, 74 min; 120°C, 40 min) and then stored for up to 6 years. Analyses (lipid oxidation and hydrolysis, browning and formation of fluorescent compounds) of the lipids extracted from the white muscle of the fish and the packing oils were carried out. Muscle lipids were partially extracted by the packing oil, so that an increase in the storage time produced higher levels of free fatty acids, browning and fluorescence development in the packing oils. As regards the types of muscle, little difference between them throughout the canned storage was detected. Received: 17 February 1997 / Revised version: 12 May 1997     

工程陶瓷超声振动辅助下的预压应力压痕试验

提出了一种超声振动辅助加工下的预压应力压痕试验,采用ZrO₂、95% Al₂O₃、SiC工程陶瓷作为试验材料,研究外部载荷对材料的加工损伤影响机理。结果表明,在无预压应力压痕过程中,3种材料的加工损伤表现出不同的形式,如径向裂纹、边缘破损和微裂纹;在预压应力压痕过程中,不论是相同法向负载还是相同压痕深度条件下,上述材料的加工损伤都受到了不同程度的抑制,同时证实了预压应力会加大压痕过程的法向力,减小压痕深度。在超声振动辅助下的预压应力压痕试验过程中,由于超声振动的作用机理,有效减小了压痕过程的法向力、增大了压痕深度,有利于工程陶瓷的高效低损伤加工。     

隧洞开挖爆破超挖控制技术研究

针对隧洞开挖超挖严重、开挖断面成形差的情况,探讨了超挖造成的影响和危害,论证了单循环进尺与超挖量是平方关系,单循环进尺较小时采用长钻杆钻孔有利于减小外偏角、减少超挖。并从施工技术、爆破技术和施工管理技术的角度提出了隧洞开挖时控制超挖的有效方法,可供隧洞施工参考。     

Unified damage description and risk assessment of buildings under extreme natural hazards

Internationally different classification schemes are available for the assessment of structural damage due to the different natural hazards. Due to their heterogeneity, these classification schemes are insufficiently suited for the consideration of damage in the sense of a multi hazard approach. A unified system is necessary for the evaluation of the building vulnerability and the damage prognosis due the different natural hazards. The unified system transfers repeatedly observed damage patterns into a scheme of damage grades. With this instrument, the structural damage can be uniformly evaluated and the relationship to the input parameters can be established. Following the concept of the European Macroseismic Scale 1998 (EMS‐98) for earthquake damage, it is distinguished between structural and non‐structural damage to which characteristic damage patterns can be assigned in the form of damage grades. A general classification scheme for building damage is presented, which enables a comparison of the damage due to the individual natural hazards. On the basis of real observed damage cases, the typical damage patterns for the natural hazards flood, tsunami and wind are highlighted and converted into harmonized classification schemes for damage grades. For the first time, a harmonized set of instruments is available for evaluation of damage cases on a building stock as a result of different natural hazards according to criteria standardized in engineering terms. The outlook refers to the damage prognosis due to the different natural hazards and their possible sequences.     

布线图案导致的集成电路平坦化损伤研究

使用化学机械抛光(CMP)的方式,对商用芯片进行拆解,获得了不同制造工艺的铜/低k介质互连结构样品。通过对所获得的32 nm制造工艺的铜/低k介质互连结构样品进行进一步的化学机械抛光实验来研究抛光过程中出现的损伤。实验结果发现,抛光压力过大和过小分别会造成宏观缺陷和导线腐蚀,互连线的分布会导致导线自身的碟型缺陷、不同图案布线结构交界两侧明显的表面高度差异以及同一图案布线结构内部的表面周期性高度起伏。这种表面高度差异可以通过预补偿的方式得到一定的改善。