船用电器柜抗冲击设计研究

为增强船内部电器柜的抗冲击性能,采用有限元法对船内不同安装型式的电器柜结构进行了模态和抗冲击性能仿真分析,通过对比分析得出了使用撑杆加固型式安装的电器柜能显著提高船内电器柜的抗冲击性能的结论,并确定了电器柜抗冲击优化设计方案。     

CIMS在造船生产管理中的应用

CIMS是计算机集成制造系统的简称,上世纪九十年代起已经开始广泛应用于现代制造领域,而造船行业则属于计划性比较强的领域,尤其是在目前市场环境比较低迷,企业间竞争比较激烈的情况下,如何利用现代化的工具,做好资源调配,从管理中挖掘效益,是各个造船企业必将采取的手段之一,本文结合我公司的实际使用情况对此进行简要说明。     

国内外规范关于水流作用下护底块石稳定质量计算方法对比

关于水流作用下护底块石的稳定质量计算，国内外均开展了大量研究，并总结提出多种计算理论，各国规范也给出不同的计算方法。因研究条件和背景有所不同，采用各种计算方法往往得到不同的计算结果，给设计人员带来较多不便。针对上述问题，梳理国内外常用规范中给出的计算方法，并结合工程案例进行对比分析，总结不同方法之间的差异以及适用条件。结果表明，水深是影响护底块石质量的敏感因素，计算方法选取时应重点考虑该因素；美国规范考虑的影响因素较为全面，具有较好的适用性；但在强紊动的水流条件下，建议对照国际通用手册中的Pilarczyk法和Escarameia & May法综合评估确定块石质量。     

Novel experimental strategy for high resolution AFM imaging of membrane-associated bacterial toxins

Bacterial pore-forming toxins （PFTs） are essential virulence factors of many human pathogens. Knowl- edge of their structure within the membrane is critical for an understanding of their function in pathogenesis and for the development of useful therapy. Atomic force microscopy （AFM） has often been employed to structurally interrogate many membrane proteins, including PFTs, owing to its ability to produce sub-nanometer resolution images of samples under aqueous solution. However, an absolute prerequisite for AFM studies is that the samples are single-layered and closely-packed, which is frequently challenging with PFTs. Here, using the prototypical member of the cholesterol-dependent cytolysin family of PFTs, perfringolysin O （PFO）, as a test sample, we have developed a simple, highly robust method that routinely produces clean, closely-packed samples across the entire specimen surface. In this approach, we first use a small Teflon well to prepare the supported lipid bilayer, remove the sample from the well, and then directly apply the proteins to the bilayer. For reasons that are not clear, bilayer preparation in the Teflon well is essential. We anticipate that this simple method will prove widely useful for the preparation of similar samples, and thereby enable AFM imaging of the greatest range of bacterial PFTs to the highest possible resolution.     

Robust control for four-wheel-independent-steering electric vehicle with steer-by-wire system

A four-wheel-independent-steering (4WIS) electric vehicle (EV) with steer-by-wire (SBW) system is proposed in this paper. The fast terminal sliding mode controller (FTSMC) is designed for the SBW system to suppress external disturbances. Taking unstructured and structured uncertainties into consideration, a robust controller is designed for the 4WIS EV utilizing μ synthesis approach and the controller order reduction is implemented based on Hankel-Norm approximation. Since sideslip angle is the feedback signal of robust controller and it is hard to measure, the extended Kalman filter (EKF) is employed to estimate sideslip angle. To evaluate the vehicle performance with the designed control system, step and sinusoidal steering maneuvers are simulated and analyzed. Simulation results show that the designed control system have good tracking ability, strong robust stability and good robust performance to improve vehicle stability and handing performance.     

A signal-based fault detection and classification method for heavy haul wagons

This paper proposes a signal-based fault detection and isolation (FDI) system for heavy haul wagons considering the special requirements of low cost and robustness. The sensor network of the proposed system consists of just two accelerometers mounted on the front left and rear right of the carbody. Seven fault indicators (FIs) are proposed based on the cross-correlation analyses of the sensor-collected acceleration signals. Bolster spring fault conditions are focused on in this paper, including two different levels (small faults and moderate faults) and two locations (faults in the left and right bolster springs of the first bogie). A fully detailed dynamic model of a typical 40t axle load heavy haul wagon is developed to evaluate the deterioration of dynamic behaviour under proposed fault conditions and demonstrate the detectability of the proposed FDI method. Even though the fault conditions considered in this paper did not deteriorate the wagon dynamic behaviour dramatically, the proposed FIs show great sensitivity to the bolster spring faults. The most effective and efficient FIs are chosen for fault detection and classification. Analysis results indicate that it is possible to detect changes in bolster stiffness of ±25% and identify the fault location.     

基于灰色残差GM（1，1）模型的道路交通量预测的研究

道路交通体系是一个多因素、多层次、多目标的复杂系统。其中交通量信息系统具有明显的层次复杂性,结构关系的模糊性,动态变化的随机性,指标数据的不完全和不确定性。由于技术方法、人为因素、自然环境变化的影响,造成各种数据误差、短缺甚至虚假现象,系统的作用机制不明确,系统的状态、结构、边界关系难以精确描述,属于典型的灰色系统。在作量化、模型化、实体化研究时,能作为反映系统主要动态特征的数据是很少的。由于环境对系统的干扰,系统信息中原始数据序列往往呈现离乱情况,离乱数列即为灰色数列或称灰色过程,灰色理论利用那些较少的或不确切的表示系统行为特征的原始数据序列作生成变换后建立微分方程,对灰色过程建立的模型称为灰色模型（Greymodel）,简称GM模型。本文从理论上介绍了GM（1,1）模型和灰色残差GM（1,1）模型建立的一般过程,然后将其应用于交通量预测的实际例子中。预测结果表明,该方法是可行的。     

TNFα、Leptin-Rb、NF-κB和PPAR-γ在酒精性肝病大鼠肝细胞中的表达

目的 探讨TNFα、NF-κB、Leptin-Rb和PPAR-γ等在大鼠酒精性肝病中与肝组织炎症、坏死和纤维化的关系.方法 胃造瘘法建立长期大鼠酒精性肝病模型,分别在第4、8、12、24和52周用免疫组化、原位杂交和RT-PCR技术检测不同阶段大鼠肝组织中TNFα、NF-κB、PPAR-γ和Leptin-Rb等的表达.结果 TNFα、NF-κB和Leptin-Rb水平在模型组大鼠肝细胞中,第8周表达逐渐增强,第24周起高水平表达一直持续至52周(P<0.01).PPAR-γ在对照组和第4、8周模型组肝细胞中表达最强,第12周表达开始减弱.TNFα和NF-κB在肝细胞中的表达呈明显正相关关系,与PPAR-γ则呈负相关关系(P<0.01).结论 TNFα和NF-κB与肝细胞病变程度有很好的一致性关系,Leptin-Rb在肝细胞的表达与肝纤维化发展相一致,PPAR-γ则刚好相反.     

5-羟色胺转运体基因多态性和抑郁症的发病、性别、严重程度及自杀行为的相关性

目的探讨中国汉族人群5-羟色胺转运体启动区(5-HTTLPR)基因多态性和抑郁症的发病、性别、严重程度及自杀是否相关。方法应用聚合酶链式反应(PCR)扩增技术测定150例抑郁症患者和150例正常对照者的5-HT-TLPR基因型和等位基因,分别验证各种基因型与中、重度抑郁症发病、性别及自杀行为的相关性。结果病例组SS、LS基因型及S等位基因频率均高于对照组(26.0% vs.20.0%;52.7% vs.46.0%;52.3% vs.43.0%;P均<0.05);两组性别分层比较,女性S等位基因频率高于对照组(55.3% vs.43.6%,P<0.05);病例组严重程度分层比较差异无统计学意义(P>0.05);病例组有无自杀行为分层比较,有自杀行为患者SS基因型频率(37.3% vs.20.2%)及S等位基因频率(61.8% vs.47.5%)均高于无自杀行为患者(P<0.05);抑郁自杀组性别分层比较未显示显著性差异(P>0.05);抑郁自杀组病情程度分层比较,重度抑郁自杀者SS基因型频率(42.5% vs.18.2%)及S等位基因频率(68.7% vs.36.4%)均高于中度抑郁自杀者(P<0.05)。结论在中国汉族人群中,5-HTTLPR多态性和抑郁症相关。S等位基因可能是抑郁症的易感基因,特别是女性,SS型可能是抑郁症易感基因型;S等位基因可能是抑郁症患者自杀的危险基因,SS基因型人群可能是抑郁症患者自杀的危险人群,特别是携带S等位基因的重度抑郁症患者更易自杀。     

Singular perturbation composite control of a free-floating flexible dual-arm space robot

The Free-floating Flexible Dual-arm Space Robot is a highly nonlinear and coupled dynamics system. In this paper, the dynamic model is derived of a Free-floating Flexible Dual-arm Space Robot holding a rigid payload. Furthermore, according to the singular perturbation method, the system is separated into a slow subsystem representing rigid body motion of the robot and a fast subsystem representing the flexible link dynamics. For the slow subsystem, based on the second method of Lyapunov, using simple quantitative bounds on the model uncertainties, a robust tracking controller design is used during the trajectory tracking phase. The optimal control method is designed in the fast subsystem to guarantee the exponential stability. With the combination of the two above, the system can track the expected trajectory accurately, even though with uncertainty in model parameters, and its flexible vibration gets suppressed, too. Finally, some simulation tests have been conducted to verify the effectiveness of the proposed methods.