北留环镇公路隧道施工坍塌处治措施

通过从地质条件、施工等方面综合分析,探讨了北留环镇公路隧道坍塌的成因,提出采取地表注浆加固以及加强初期支护等施工处治措施。通过施工监控量测和动态跟踪,证明该处治方案较为合理,对类似地质区防坍塌有一定的参考价值。     

Recycling of aluminum from fibre metal laminates

Recycling of aluminum alloy scrap obtained from delaminated fibre metal laminates (FMLs) was studied through high temperature refining in the presence of a salt flux. The aluminum alloy scrap contains approximately mass fraction w(Cu) = 4.4%, w(Mg) = 1.1% and w(Mn) = 0.6% (2024 aluminum alloy). The main objective of this research is to obtain a high metal yield, while maintaining its original alloy compositions. The work focuses on the metal yield and quality of recycled Al alloy under different refining conditions. The NaCl-KCl salt system was selected as the major components of flux in the Al alloy recycling. Two different flux compositions were employed at NaCl to KCl mass ratios of 44:56 and 70:30 respectively, based on either the eutectic composition, or the European preference. Different additives were introduced into the NaCl-KCl system to study the effect of flux component on recycling result. Although burning and oxidation loss of the alloying elements during re-melting and refining take place as the drawbacks of conventional refining process, the problems can be solved to a large extent by using an appropriate salt flux. Experimental results indicate that Mg in the alloy gets lost when adding cryolite in the NaCl-KCl salt system, though the metal yield can reach as high as 98%. However, by adding w(MgF₂) = 5% into the NaCl-KCl salt system (instead of using cryolite) all alloying elements were well controlled to its original composition with a metal yield of almost 98%.     

Biocompatibility evaluation of polyethylene terephthalate artificial ligament coating hydroxyapatite by fibroblasts cells in vitro

Hydroxyapatite (HA) based materials have been widely used in the field of ligament tissue engineering in the past decades. It has been previously reported that HA can increase the penetration of marrow-derived mesenchymal stem cells (MSCs) and MSCs cells into scaffolds due to increased cell differentiation in biological media. Additionally, it was found that there are much difference between MSCs and anterior cruciate ligament (ACL) cells. For that reason, we mainly evaluate the biocompatibility of polyethylene terephthalate (PET) silk scaffold with fibroblasts cells in vitro. We cultured mouse fibroblasts cells on the substrate of PET fiber and PET-HA scaffold, respectively, and then observed the morphology by using scanning electron microscopy. Our data indicate that PET-HA scaffold has good biocompatibility with fibroblasts cells and can potentially be useful in enhancing the fibroblasts cell differentiation and proliferation.     

Investigation on blanking of thick sheet metal using the ductile fracture initiation and propagation criterion

In metal forming processes such as sheet blanking, severe plastic deformation localizes in a narrow shear band near blanking clearance, and ductile fracture occurs at the final stage. Because the combinations of large nonlinear strain localization, displacement discontinuity and ductile fracture brought obstacles to numerical simulation, a ductile fracture initiation criterion model and an elasto-plastic finite element method (FEM) were presented to simulate localized severe plastic deformation. Initiation and propagation of cracks were treated by deletion-and-replacement approach. The distributions and developing trends of effective strain and damage were predicted, the influence of blanking clearance on fracture was discussed, and an experiment was performed to explore the forming mechanism.     

A method for determining surface free energy of bamboo fiber materials by applying Fowkes theory and using computer aided machine vision based measurement technique

The purpose of this study is to develop a standard methodology for measuring the surface free energy (SFE), and its component parts of bamboo fiber materials. The current methods was reviewed to determine the surface tension of natural fibers and the disadvantages of techniques used were discussed. Although numerous techniques have been employed to characterize surface tension of natural fibers, it seems that the credibility of results obtained may often be dubious. In this paper, critical surface tension estimates were obtained from computer aided machine vision based measurement. Data were then analyzed by the least squares method to estimate the components of SFE. SFE was estimated by least squares analysis and also by Schultz?? method. By using the Fowkes method the polar and disperse fractions of the surface free energy of bamboo fiber materials can be obtained. Strictly speaking, this method is based on a combination of the knowledge of Fowkes theory. SFE is desirable when adhesion is required, and it avoids some of the limitations of existing studies which has been proposed. The calculation steps described in this research are only intended to explain the methods. The results show that the method that only determines SFE as a single parameter may be unable to differentiate adequately between bamboo fiber materials, but it is feasible and very efficient. In order to obtain the maximum performance from the computer aided machine vision based measurement instruments, this measurement should be recommended and kept available for reference.     

一种汽车启动机智能保护装置的设计

汽车启动机属于汽车的易损坏部件之一.文中所设计的保护装置通过采集汽车点火开关信号、温度传感器信号、汽车变速箱信号、发送机转速信号等,利用AVR系列单片机为控制器,对启动机的电路通断状态、启动频率、启动持续时间等进行控制.保护装置能够有效保证启动机的工作环境和工作条件,避免误操作和过热造成的损坏,从而延长启动机的使用寿命,并保障汽车启动时的安全.     

创新校企合作模式，开展全方位教学改革

结合骨干院校重点建设项目——汽车专业（群）建设,广东交通职业技术学院汽车学院开展校企校企合作建设模式的研究与实践,创新“院内国际名企培训中心＋院外品牌汽车4S店”校企合作模式,推动了人才培养模式改革和师资队伍建设等工作,提高了人才培养质量。     

图书供应商评价体系的研究及应用

针对图书馆在图书采购中选择满意的图书供应商,根据图书馆文献建设的特点,可建立由服务能力、影响力、供应能力、交货能力和价格五大决策目标及12个评价指标组成的图书馆图书供应商评价选择模型,并运用改进的TOPSIS方法对决策模型进行了求解。结果表明,该方法为图书馆在图书采购中正确选择供应商提供了依据。     

民用机场建设贯彻国防要求初探

民用机场具有重要的平战运输保障功能,在民用机场规划设计、新建及改扩建过程中,不失时机地提出国防要求并加以落实,可为提高机场平战时航空军事运输保障功能、增强航空战略投送能力奠定坚实基础。阐述了民用机场的国防与军事价值,分析了我国民用机场建设贯彻国防要求存在的主要问题,探讨了民用机场贯彻国防要求的项目、内容及技术要求等,为民用机场建设贯彻国防要求提供技术参考。     

高科技园区步行和自行车交通系统构建——以北京市中关村科技园区电子城北扩区为例

为构建高科技园区安全、便捷、舒适的步行和自行车交通系统,从分析高科技园区特征以及步行和自行车交通的必要性入手,归纳总结其步行和自行车交通系统构建的技术路线和方法,提出规划、设计、管理不同阶段需要重点解决的问题。以北京市中关村科技园区电子城北扩区为例,探讨在规划、设计、管理中落实步行和自行车交通系统优先的途径。从步行和自行车交通需求特征、功能定位、与其他交通系统的关系角度详细阐述步行和自行车通道和节点规划方案。同时,探讨如何在设计和管理阶段落实规划中步行和自行车交通优先理念的具体对策。