Advanced Materials Research Vols. 834-836

Abstract: With the developing of integrated circuit(IC) technique, improving of integration level, reducing of feature size and increasing the wafer size, the stringent requirements for global planarization during IC fabrication are raised. During chemical mechanical polishing(CMP) of multilevel interconnect for IC, there are obvious influence of the polishing quality on performances of the device．CMP slurry is one of the important factors of influencing the polishing quality. In this work, the stability of tungsten plug CMP slurry for IC multilevel interconnect was studied. Through experiment, interaction between the components in the CMP slurry was analyzed, and stable slurry with optimized polishing parameters to achieve higher removal rate were defined．

Abstract: Superhydrophobic surfaces on metal substrates are often prepared via roughing the surfaces and lowering their surface energy. Composite brush plating technique is developed to prepare superhydrophobic n-SiO₂/Ni brush plating composite coating on copper surfaces. Under the better process parameters, the water contact angle of the obtained superhydrophobic surface is approximately 160°, and the water sliding angle is less than 10°. The influences of plating voltage and plating time on the coating surface structure and hydrophobicity were discussed. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).The results show that the prepared surfaces have the appearance of the uniform micron papilla-like structures, which are composed of submicron globular Ni particles covered with n-SiO₂ nanoscale villiform structures. These hierarchical micro/nanostructures are similar to the lotus leaf and play an important role in gaining superhydrophobicity. It is expected that this sample technique will be widely used for large-scale production of superhydrophobic engineering materials.

Abstract: The mode-I fracture of adhesive surface was studied by uniaxial tensile test of the double cantilever beam (DCB) adhesive joints which were made from aluminium sheet and Hydroxyl-terminated polybutadienec (HTPB). The load - displacement curves which characterize the response of the macroscopic fracture show a significant rate-dependent property, i.e. the peak load and corresponding displacement increase with the increase of the loading rates. The critical energy release rate has been defined in two waysnon-linear initiation point (NL) and the maximum load point based on the experimental curves, was gained by the corrected beam theory of fracture mechanics. In addition, the cohesive parameters-fracture energy was also decided by the inversion identification method. The fracture energy obtained numerical simulation is slightly greater than the value obtained by the corrected beam theory, but both results indicate the fracture energy of the adhesive interface also increases continuously with increasing loading rates.

Abstract: The prediction model is proposed in this paper to predict the displacement of foundation pit. In the model, genetic algorithms is applied to optimize the node function of the neural network (15 node function coefficients are optimized simultaneously). Next, do the further optimization to the model, and GA-transFcn3 Model is established whose fitness evaluation takes into account the multi-step prediction error. Finally, it is verified that the GA-transFcn3 Model created in this article has the desirable prediction accuracy through engineering examples. The establishment of GA-transFcn3 Model can provide researchers and engineers with ideas and methods for the displacement prediction of foundation pit, and can be popularized and applied in practical projects.

Abstract: The post-earthquake reconstruction aims to assist the earthquake survivors return to their normal lives physically and mentally. This paper examined three post-disaster reconstruction cases occurred in the west of China and deciphered that facing the short-term and massive projects in the reconstruction process, the decision makers and designers utilized the non-local materials and modern technologies produced plenty of modern structures which were not completely fit the local social and physical environments. After conducting fieldtrips and interviews in these quake-hit areas, this paper suggested the decision makers and designers to learn from the local traditional architectural design and construction methods in order to improve their design to be suitable for the local unique cultural and physical backgrounds. To be continued, this paper proposed some improvements regarding using the modern technologies to strengthen the advantages of traditional building materials and technologies as well as avoid the traditional architectural practices weaknesses.

Abstract: Nanotechnology provides a new method on modified cement. It introduces the research and application of nanocement situation and existing problems in the paper. The nanocement has better mechanical properties and durability than the current ordinary cement, and it is environmentally friendly. It can improve the microstructure of cement in order to improve their physical and mechanical properties and durability, and it can reduce energy consumption. The current focus is to study the microstructure and mechanical properties of nanoconcrete, as well as how to prepare inexpensive nanomaterials. Future, the nanocement will have a wider application field.

Abstract: Due to the restraint of steel tube concrete of concrete filled steel tubular components，three directions’ compression at the same time， the bearing capacity of concrete is obviously improved.As a result of the existence of steel pipe concrete，can effectively prevent the steel tube of local buckling ，com-plementary advantages and disadvantages of these two kinds of material ， the performance of the material is greatly improved. In this paper, the performance and characteristics of the composite material has carried on the detailed instructions，the ultimate bearing capacity of calculation principle has carried on the detailed analysis and research， the application of this new type of material are summarized.

Abstract: The present work assesses the seismic restoration of a primary school in Arcola (Italy) made by a r.c. framework, built in the 60s and affected by high seismic vulnerability. The reinforcement is made by a set of four steel frameworks applied in the outside façades of the school. Results of cost-effectiveness and seismic safety were achieved, together with a quick and easy execution of the intervention.

Abstract: In order to evaluate the construction quality of a bridge, the finished line-shape and the actual stress state are two key parameters to check whether it’s consistent with the design requirements. However, there are many factors during the construction to make the actual completion state deviate from what is theoretically expected. The main purpose of construction control is to detect the deviations and thus correct them, and at the same time to predict and control the potential deviations so as that the completion state of a bridge (including the finished line-shape and structural internal force) could meet its design requirements. North Central Bridge in Taiyuan City is an irregular cable-stayed bridge which has five spans, five anti-symmetric steel arches and five anti-symmetric cable planes. As the bridge has a special structure shape and the control of the steel arch shape during the construction is quite difficult, the finite element analysis software is employed to analyze the construction process, therefore to make the rational construction control scheme of the arch shape and the stress state. The analysis results of this construction control scheme can be used as reference for others similar bridges in the future.

Abstract: With pumice as the additive agent used in cement composite soil . In order to test the strength of the composite cement soil, the unconfined compression resistance were tested in the lab with different additive quantity (4%,8%,12%,16%), different curing periods (7d,28d,60d), The results show that the strength of the composite cement soil are significantly increase with increasing curing periods , with increasing additive quantity the strength variation of the composite cement soil first added, and then reduces. there is an optimum amount 8%.The pumice powder may evidently improve the mechanical properties of soft soil which has the characteristic of rich-water content, when water content from 12% to 19%, the strength of the composite cement soil are increased about 20%.