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Magnetostriction varieties and stress relief caused by pulsed magnetic field

Zhipeng CAI, Xinjie DUAN, Jian LIN, Haiyan ZHAO

《机械工程前沿（英文）》 2011年第6卷第3期页码 354-358 doi: 10.1007/s11465-011-0123-4

摘要：

Magnetostriction is investigated to evaluate the stress relief caused by pulsed magnetic field treatment, because this physical property is closely associated with residual stress. Magnetostriction of different stressed samples is measured in this paper. The stress variations caused by pulsed magnetic treatment are also compared. It is found that magnetostriction variations are closely associated with stress changes. Thermodynamic potential is used to find the relationship between them. Based on several assumptions, we find that the product of magnetostriction amplitude and stress magnitude is nearly a constant during magnetic field treatment, which is valuable for stress relief evaluation and optimizing processing parameters. This conclusion is testified by stress measurements, and the calculated values are in accordance with the experiment results.

关键词： magnetostriction pulsed magnetic field treatment stress relief

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Dimensionality reduction and prediction of soil consolidation coefficient using random forest coupling with Relief

Hai-Bang LY; Huong-Lan Thi VU; Lanh Si HO; Binh Thai PHAM

《结构与土木工程前沿（英文）》 2022年第16卷第2期页码 224-238 doi: 10.1007/s11709-022-0812-6

摘要： The consolidation coefficient of soil (C_v) is a crucial parameter used for the design of structures leaned on soft soi. In general, the C_v is determined experimentally in the laboratory. However, the experimental tests are time-consuming as well as expensive. Therefore, researchers tried several ways to determine C_v via other simple soil parameters. In this study, we developed a hybrid model of Random Forest coupling with a Relief algorithm (RF-RL) to predict the C_v of soil. To conduct this study, a database of soil parameters collected from a case study region in Vietnam was used for modeling. The performance of the proposed models was assessed via statistical indicators, namely Coefficient of determination (R²), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE). The proposal models were constructed with four sets of soil variables, including 6, 7, 8, and 13 inputs. The results revealed that all models performed well with a high performance (R² > 0.980). Although the RF-RL model with 13 variables has the highest prediction accuracy ( R² = 0.9869), the difference compared with other models was negligible (i.e., R² = 0.9824, 0.9850, 0.9825 for the cases with 6, 7, 8 inputs, respectively). Thus, it can be concluded that the hybrid model of RF-RL can be employed to predict C_v based on the basic soil parameters.

关键词： soil consolidation coefficient machine learning random forest Relief

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Photoinduced dichroism and surface-relief-gratings of hyperbranched azo polymers synthesized by azo-coupling

CHE Pengchao, HE Yaning, WANG Xiaogong

《化学科学与工程前沿（英文）》 2007年第1卷第4期页码 360-364 doi: 10.1007/s11705-007-0065-x

摘要： This article reports the synthesis and photoresponsive properties of a hyperbranched azo polymer containing electron donor-acceptor type azo chromophores both in backbone and peripheral positions. For the synthesis, a hyperbranched azo precursor polymer was synthesized by step-growth polymerization of an AB monomer, bis[2-(-ethylanilino)ethyl] 5-aminoisophthalate, through azo-coupling reaction. The hyperbranched precursor polymer was then reacted with the diazonium salt from 4-cyanoaniline to introduce donor-acceptor azo chromophores in the peripheral groups. The resulting azo polymers were characterized by the spectroscopic methods and thermal analysis. The photoinduced dichroism of the hyperbranched polymer was studied and its orientation order parameter was estimated to be 0.063. Thin films of the hyperbranched azo polymers were used to fabricate surface-relief-gratings (SRGs) by exposing them to an interference pattern of Ar laser beam at modest intensities (150 mW/cm). The azo chromophores introduced by post-azo-coupling reaction at the para-positions of the peripheral azobenzenes shows a significant effect on the SRG inscription rate. The hyperbranched azo polymers can potentially be used for applications such as reversible optical data storage, photoswitch, sensors, and other photo-driven devices.

关键词： inscription 4-cyanoaniline orientation peripheral photoswitch

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利用机载激光雷达和近地表地球物理方法空间识别复杂低幅度第四纪硅质碎屑岩层——以美国得克萨斯滨海平原为例 Article

Jeffrey G. Paine,Edward W. Collins,Lucie Costard

《工程（英文）》 2018年第4卷第5期页码 676-684 doi: 10.1016/j.eng.2018.09.005

摘要：

保存在全球滨海平原上的沉积单元控制着浅地层岩性分布，这对基础设施的设计和建设至关重要，同时也是许多第四纪冰期—间冰期循环中发生大规模气候变化的重要信息库。我们对这些沉积单元的横纵向岩性、地层复杂性及其对气候和海平面变化的响应知之甚少，因此很难预测岩性分布，以及将发展历史、未来气候和海平面变化置于同一自然地质环境中。传统上在低幅度滨海平原上描绘的第四纪硅质碎屑沉积单元建立在航拍图和低分辨率地形图的基础上。低幅度和低曝光率影响了观测的准确性和精确性。高分辨率机载激光雷达探测、地表地球物理勘探和地球物理测井正被用于识别得克萨斯州滨海平原上第四纪地层岩性单元的精确横纵向边界。地表和井中电导率测量能从泥质泛滥平原、三角洲平原和河道沉积中区分出砂质障壁岛、河流和三角洲河道沉积物。井中电导率和自然伽马测井记录同样可以区分地下不同的岩性单元，并识别出可能在不同冰期- 间冰期阶段分离的沉积单元的侵蚀不整合面。从机载激光雷达探测获得的高分辨率数字高程模型揭示了以前不为人知的地形细节，有助于识别地表特征，如砂质通道、富含黏土的河间沉积和更新世障壁岛上的堆积特征。在低幅度滨海平原环境中识别岩性和地层分布的最佳方法是：①首先使用激光雷达探测生成详细的高程模型；②基于激光雷达数据和航拍图的初步定位，选择性进行地表采样和地球物理探测；③在激光雷达和地表探测完成后，选择关键位置进行钻孔取样、测井和分析。

关键词：岩性地球物理电磁感应激光雷达