海洋溴酚化合物BDDPM促进肝糖原合成及缓解胰岛素抵抗的作用研究

BDDPM是一种从海洋松节藻中分离出来的全新结构的溴酚类化合物,前期研究表明BDDPM具有良好的PTP1B蛋白酶活抑制能力。在本文中利用Hep G2细胞和C2C12细胞,研究BDDPM对肝细胞糖原合成能力的影响及对胰岛素抵抗的作用。结果表明,1μmol/L BDDPM可以在细胞水平显著激活胰岛素信号通路,提高肝糖原的合成,缓解棕榈酸诱导的胰岛素抵抗,初步具有开发成为新型抗糖尿病海洋药物的潜力。     

基于BP神经网络的变形三体船布局优化研究

针对以DTMB5415为基础船型提出的高速可变形三体船,以CFD软件计算结果为样本值,利用BP神经网络方法对三体船静水阻力进行多次训练,在保证精度的基础上模拟预测了多组不同航速、不同布局下的单位排水量阻力值,从而得出了随航速变化下该船型可调节的适航布局。BP神经网络法较之传统CFD计算不仅能极大的缩短计算时间,而且能快速可靠的搜索到任意航速下能耗最小的布局,打破了CFD方法必须通过限定布局和航速求得阻力值来进行比较的固有模式,真正实现了三体船"可变形"的优势,工程适用性强,为计算机辅助三体船布局优化研究提供了一种新思路。     

Neural Network Model for Predicting the Resistance of Driven Piles

Although numerous investigations have been performed over the years to predict the behavior and resistance of piles, the mechanisms are not yet entirely understood. Predicting pile resistance is a difficult task because there are a large number of parameters affecting the capacity that have complex relationships with each other. It is extremely difficult to develop appropriate relationships between various essential parameters, including the soil condition, pile type, driving condition, time effect, and others. This paper describes the application of an artificial neural network (ANN) to predict the resistance of driven piles in dynamic load tests. The training and testing of the ANN were based on 165 data points for driven piles at various construction sites in Korea. Predictions on the tip, shaft, and total pile resistance were made for piles with available corresponding measurements of such values. The effect of the essential parameters on the pile resistance values was investigated through parametric analysis using ANN modeling. The results of this study indicate that the ANN model serves as a reliable and simple predictive tool to appropriately consider various essential parameters for predicting the resistance of driven piles.     

Influence of vacuum preloading on vertical bearing capacities of piles installed on coastal soft soil

Abstract

Land reclamation has increased significantly in the eastern coastal areas of China. The increased exploitation of offshore resources has made cast-in-situ piles more preferable in these regions. However, precise prediction of axial forces and shaft resistances of piles is particularly difficult because geological conditions are complex after the foundation is treated by vacuum preloading. In this study, two groups of cast-in-situ piles, each of which consisted of two piles installed in soft soil in Oufei Project, Wenzhou, China, were compared by conducting tests using the slow static loading method to evaluate the influence of applying vacuum preloading to deal with soft soil foundation on the vertical bearing capacities of the piles. Two piles were located in an untreated area, while the other two were located in a vacuum preloading treating area. All the piles had the same length and diameter. In addition, the axial forces and shaft resistances of piles were calculated based on the measured strains. The field tests revealed that the ultimate bearing capacities and shaft resistances of test piles were significantly improved compared to those of the piles in untreated area. The experimental results presented in this study are expected to be highly beneficial for practical engineering.     

Calibration of LRFD Format for Steel Jacket Offshore Platform in China Offshore Area （2） ： Load, Resistance and Load Combination Factors

1.IntroductionLoad and Resistance Factor Design(LRFD)isthe commonly adoptedreliability-based designfor-mat for structural design(CNE,1990;AAHTO,1994;OMTC,1983;CMC,1984).Code calibra-tionforthe LRFDformat is a processto determinethetarget reliability by de…     

Global buckling of pipelines in the vertical plane with a soft seabed

Offshore pipelines are usually buried to avoid damage from fishing activities and to provide thermal insulation. Provided that the buried pipelines are sufficiently confined in the lateral direction by the passive resistance of the trench walls, they may be subject to vertical buckling caused by a rise in temperature. Vertical buckling is usually called upheaval buckling because the heated pipeline is assumed to move upwards conventionally. However, the seabed may be very soft, especially where a pockmark or abyssal ooze appears. Consequently, under thermal compressive force, the pipeline may buckle downward and penetrate into the seabed because the downward soil resistance is small. In this study, we extended an analytical solution for vertical pipeline buckling on a rigid seabed to a soft seabed, and the effects of soil resistance on pipeline stability, buckling mode and amplitude are illustrated and analyzed.     

外源添加剂水杨酸对菊花江蓠抗寒性的影响

通过室内实验生理生态学的方法研究了外源添加剂水杨酸(SA)对菊花江蓠(Gracilaria lichevoides)抗寒性的影响.研究表明,通过添加0.5 mmol/L的SA,可以明显降低(实验组)江蓠的丙二醛(MDA)积累量、电解质渗透率;其脯氨酸含量、特定生长率(RsG)、超氧化物歧化酶(SOD)、过氧化物酶(PO...     

Pressure resistance of the corrugated stainless steel membranes of LNG carriers

Corrugated stainless steel membranes have been used as the primary barriers for LNG carriers to reduce thermal stresses at cryogenic temperatures. As the capacity of the LNG cargo is increased, however, the corrugated stainless steel membranes suffer from buckling and collapse due to increased sloshing loads in large-capacity LNG cargo carriers. In this study, the pressure resistance of the corrugated part of the stainless steel membrane was evaluated using a finite element method for better design of the LNG containment system, and an experimental equipment was developed and the pressure resistance of the stainless steel corrugations was measured and compared with the calculated results. In addition, a new membrane with high-pressure resistance and its reinforcing method were developed and evaluated experimentally.     

离岸裙式吸力基础在砂土地基中沉贯性研究

吸力基础是海洋工程中新型的一种基础型式,广泛应用于海洋平台、海洋浮动式结构等,近年来,也被作为浅海离岸风力发电工程的基础。吸力基础易遭受较大的水平动力荷载和弯矩,从而可能产生较大水平位移和转角;同时,由于海床冲刷,会降低其承载能力。为克服这些不足,提出了一种新型吸力基础———裙式吸力基础,把分析传统吸力基础砂土中的沉贯方法,拓广到裙式吸力基础中,研究该基础型式在砂土中的可沉贯性以及所需的吸力;并与同情况下的传统吸力基础进行了比较,证明了所提出的裙式吸力基础具有较好的沉贯性能,具有工程实践推广价值。     

Time domain three-dimensional fully nonlinear computations of steady body–wave interaction problem

Three-dimensional fully nonlinear waves generated by moving disturbances with steady forward speed without motions are solved using a mixed Eulerian–Lagrangian method in terms of an indirect boundary integral method and a Runge–Kutta time marching approach which integrates the fully nonlinear free surface boundary conditions with respect to time.A moving computational window is used in the computations by truncating the fluid domain (the free surface) into a computational domain. The computational window maintains the computational domain and tracks the free surface profile by a node-shifting scheme applied within it. An implicit implement of far field condition is enforced automatically at the truncation boundary of the computational window.Numerical computations are applied to free surface waves generated by Wigley and Series 60 hulls for the steady problem. The present numerical results are presented and compared with existing linear theory, experimental measurements, and other numerical nonlinear computations. The comparisons show satisfactory agreements for these hydrodynamic problems.