柴油机气缸盖的模态分析

利用有限元法对柴油机气缸盖进行了模态分析,获得了气缸盖的基本振型和相关频率,与试验结果进行比较,两者有较好的一致性,因而可利用所建立的有限元模型完成气缸盖的动态响应分析及设计优化.     

大齿轮齿形在机测量原理与技术

在机测量大齿轮齿形误差具有广阔的发展前景。本文分析了大齿轮齿形误差在机测量的关键问题，提出了运用齿条刃边测头与被测齿轮横截面进行啮合的测量方法，既能测量齿轮的端截面齿形误差，又使仪器结构紧凑。在分析影响大齿轮形在机测量的诸误差因素的基础上，得出了在仪器的制造及安装精度要求不很高的情况下仍能实现齿轮的高精度测量的可喜结论。     

About the relevance of roughness parameters used for characterizing worn femoral heads

This study aims to contribute to the definition of a methodology, which can help to select a relevant roughness parameter with a view to describing the topography of orthopaedic bearing surfaces. In this investigation, the surface topography of a retrieved titanium alloy (TA6V) femoral head was characterized using visual inspection, optical microscopy and three-dimensional contacting profilometry. A numerical analysis of roughness measurements was then undertaken to assess in a first step the values of different roughness parameters of interest found in papers dealing with the topography of orthopaedic bearing surfaces. In a second step, the Analysis of Variance (ANOVA) and the Computer-Based Bootstrap Method were combined to determine statistically, and without preconceived opinion, which of those parameters is the most relevant to describe the different investigated worn regions of the studied femoral head.     

一种隧道悬臂式振动掘进机的稳定性分析

通过对隧道臂式掘进机的工作过程和切削头的受力情况进行分析，确定出掘进机容易失稳的工况，然后分别对纵向和横向稳定性进行了分析并给出计算式同时用设计参数验证了稳定性。     

Bio-information scanning technology using an optical pick-up head

We have developed a low cost and a highly compact bio-chip detection technology by modifying a commercially available optical pick-up head for CD/DVD. The highly parallel and miniaturized hybridization assays are addressed by the fluorescence emitted by the DNA-chip using the optical pick-up head. The gap between the objective lens and the bio-chip is regulated by the focus servo during the detection of the fluorescence signal. High-resolution and high-speed scanning is effectively realized by this simple scanning system instead of utilizing high-precision mechanism. Regardless of achievement of effective detection mechanism, the technique of fluorescence detection can prove to be disadvantageous because of the low stability of the dyes with low S/N ratio and an expensive setup such as a PMT detector is always required for fluorescence detection. We propose, for the first time, a novel scanning scheme based on metal nanoparticles in combination with a bio-chip substrate having a phase change recording layer. We found that the phase change process is highly affected by the existence of the densely condensed metal nanoparticles on the phase change layer during the writing process of the pick-up head.     

Influence of inoculum and climatic factors on the severity of Fusarium head blight in German spring and winter barley

Fusarium head blight (FHB) of small cereals is a disease of global importance with regard to economic losses and mycotoxin contamination harmful to human and animal health. In Germany, FHB is predominantly associated with wheat and F. graminearum is recognised as the major causal agent of the disease, but little is known about FHB of barley. Monitoring of the natural occurrence of FHB on Bavarian barley revealed differences for individual Fusarium spp. in incidence and severity of grain infection between years and between spring and winter barley. Parallel measurement of fungal DNA content in grain and mycotoxin content suggested the importance of F. graminearum in winter barley and of F. langsethiae in spring barley for FHB. The infection success of these two species was associated with certain weather conditions and barley flowering time. Inoculation experiments in the field revealed different effects of five Fusarium spp. on symptom formation, grain yield and mycotoxin production. A significant association between fungal infection of grain and mycotoxin content was observed following natural or artificial infection with the type B trichothecene producer F. culmorum, but not with the type A trichothecene-producing species F. langsethiae and F. sporotrichioides. Trichothecene type A toxin contamination also occurred in the absence of significant damage to grain and did not necessarily promote fungal colonisation.     

睢宁水厂取水设计方案比选

睢宁水厂取水工程设计规模10万m3/d,水源取自庆安水库,采用两种取水方案进行比较,方案一为框架式取水头部、架空虹吸钢管引水;方案二为箱式取水头部、钢管埋地敷设,通过两种方案比较,得出了方案二具有投资低,施工方便及安全性高的优点,并针对该方案施工中的要点提出相应的技术措施,为取水工程的设计提供参考。     

Neuroprotective Strategies for Traumatic Brain Injury: Improving Clinical Translation

Traumatic brain injury (TBI) induces secondary biochemical changes that contribute to delayed neuroinflammation, neuronal cell death, and neurological dysfunction. Attenuating such secondary injury has provided the conceptual basis for neuroprotective treatments. Despite strong experimental data, more than 30 clinical trials of neuroprotection in TBI patients have failed. In part, these failures likely reflect methodological differences between the clinical and animal studies, as well as inadequate pre-clinical evaluation and/or trial design problems. However, recent changes in experimental approach and advances in clinical trial methodology have raised the potential for successful clinical translation. Here we critically analyze the current limitations and translational opportunities for developing successful neuroprotective therapies for TBI.     

一种大型薄壁碟形封头成形工艺优化

本文针对在实际生产大型薄壁碟形封头中遇到的成形缺陷问题,提出一种新的模具拉延筋设计方案,并利用非线性有限元软件Dynaform,采用大变形弹塑性有限元模型对06Cr19Ni10覬2380mm×5.6mm碟形封头进行了模拟计算,仿真结果表明了该模具拉延筋设计方案的有效性与实用性。     

自制铁屑输送机

要输送机械加工产生的铁屑,既不能用胶带输送机,也不能用刮板输送机,为了解决这个问题,自行设计、加工制作了一种专门输送铁屑的设备——铁屑输送机,本文介绍了它的设计思路和结构原理。