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Soil seismic analysis for 2D oblique incident waves using exact free-field responses by frequency-based finite/infinite element method

《结构与土木工程前沿（英文）》 2022年第16卷第12期页码 1530-1551 doi: 10.1007/s11709-022-0900-7

摘要： The seismic analysis of a viscoelastic half-space under two-dimensional (2D) oblique incident waves is carried out by the finite/infinite element method (FIEM). First, the frequency-domain exact solutions for the displacements and stresses of the free field are derived in general form for arbitrary incident P and SV waves. With the present formulation, no distinction needs to be made for SV waves with over-critical incident angles that make the reflected P waves disappear, while no critical angle exists for P waves. Next, the equivalent seismic forces of the earthquake (Taft Earthquake 1952) imposed on the near-field boundary are generated by combining the solutions for unit ground accelerations with the earthquake spectrum. Based on the asymmetric finite/infinite element model, the frequency-domain motion equations for seismic analysis are presented with the key parameters selected. The results obtained in frequency and time domain are verified against those of Wolf’s, Luco and de Barros’ and for inversely computed ground motions. The parametric study indicated that distinct phase difference exists between the horizontal and vertical responses for SV waves with over-critical incident angles, but not for under-critical incident angles. Other observations were also made for the numerical results inside the text.

关键词： oblique incident waves critical angle half-space finite/infinite element approach seismic response analysis

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Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Dazhi WU,Lu YU

《结构与土木工程前沿（英文）》 2015年第9卷第2期页码 194-202 doi: 10.1007/s11709-015-0292-z

摘要： Considering the interactions between an embedded foundation and saturated soil, the torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic medium are analyzed in this paper. Both a rigid foundation and an elastic foundation are considered. Assuming both the side surface and the bottom surface of the foundation are perfectly bonded to soil, the reaction torques that the side soil and bottom soil acting on the foundation can be gained from basic dynamic equations of the poroelastic medium. According to the dynamic equilibrium equations of a foundation under harmonic torque, the torsional vibrations of an embedded cylindrical foundation are presented. Besides, the angular amplitude of the foundation, the equivalent stiffness and damping coefficients of the soil are expressed explicitly. Selected examples are presented to investigate the influence of relevant parameters on the torsional vibrations.

关键词： embedded foundation saturated soil rigid foundation elastic foundation torsional vibration

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What should be done for the “second half” of China’s urbanization?

Chunfei WU, Xiaojiang LI, Pengfei LI

《工程管理前沿（英文）》 2018年第5卷第2期页码 276-277 doi: 10.15302/J-FEM-2017106

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Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

《环境科学与工程前沿（英文）》 2014年第8卷第5期页码 683-692 doi: 10.1007/s11783-014-0680-y

摘要： In this paper the photolysis half-lives of the model dyes in water solutions and under ultraviolet (UV) radiation were determined by using a continuous-flow spectrophotometric method. A quantitative structure-property relationship (QSPR) study was carried out using 21 descriptors based on different chemometric tools including stepwise multiple linear regression (MLR) and partial least squares (PLS) for the prediction of the photolysis half-life ( ) of dyes. For the selection of test set compounds, a K-means clustering technique was used to classify the entire data set, so that all clusters were properly represented in both training and test sets. The QSPR results obtained with these models show that in MLR-derived model, photolysis half-lives of dyes depended strongly on energy of the highest occupied molecular orbital ( ), largest electron density of an atom in the molecule ( ) and lipophilicity (log ). While in the model derived from PLS, besides aforementioned and descriptors, the molecular surface area ( ), molecular weight ( ), electronegativity ( ), energy of the second highest occupied molecular orbital ( ) and dipole moment ( ) had dominant effects on logt values of dyes. These were applicable for all classes of studied dyes (including monoazo, disazo, oxazine, sulfonephthaleins and derivatives of fluorescein). The results were also assessed for their consistency with findings from other similar studies.

关键词： dye photolysis half-life quantitative structure-property relationship continuous-flow stepwise multiple linear regression partial least squares

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全/半双工混合蜂窝网络：用户准入和功率控制 None

Lu CHEN, Ding-zhu WEN, Cai-jun ZHONG, Guan-ding YU

《信息与电子工程前沿（英文）》 2018年第19卷第3期页码 379-387 doi: 10.1631/FITEE.1700027

摘要：考虑一个具有混合全/半双工基站的单小区蜂窝网络。对于有N条信道、K个上行用户和M个下行用户（max{K+M}≤N≤K+M）的实际场景，解决了用户准入和功率控制问题，在保证用户服务质量（QoS）的同时，最大化用户准入数量并最小化总发射功率。对于联合用户准入和功率分配问题，将该问题建模成一个0-1整数规划问题。由于寻找该问题最优解是一个NP-hard问题，通过引入“虚拟用户”的新概念，提出一种低复杂度算法。仿真结果表明，该算法和分支界定法性能相似，并且明显优于随机匹配算法的性能。

关键词：全双工；半双工；用户准入；功率控制

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descriptors into quantitative structure-property relationship models for prediction of the photolysis half-life

Yueping BAO, Qiuying HUANG, Wenlong WANG, Jiangjie XU, Fan JIANG, Chenghong FENG

《环境科学与工程前沿（英文）》 2011年第5卷第4期页码 505-511 doi: 10.1007/s11783-011-0318-2

摘要： Quantitative structure-property relationship (QSPR) models were developed for prediction of photolysis half-life ( ) of polychlorinated biphenyls (PCBs) in water under ultraviolet (UV) radiation. Quantum chemical descriptors computed by the PM3 Hamiltonian software were used as independent variables. The cross-validated value for the optimal QSPR model is 0.966, indicating good prediction capability for lg values of PCBs in water. The QSPR results show that the largest negative atomic charge on a carbon atom ( ) and the standard heat of formation (Δ ) have a dominant effect on values of PCBs. Higher values or lower Δ values of the PCBs leads to higher lg values. In addition, the lg values of PCBs increase with the increase in the energy of the highest occupied molecular orbital values. Increasing the largest positive atomic charge on a chlorine atom and the most positive net atomic charge on a hydrogen atom in PCBs leads to the decrease of lg values.

关键词： photolysis polychlorinated biphenyls (PCBs) quantitative structure-property relationships (QSPRs) quantum chemical descriptors

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The “Tiangong” Chinese Space Station project

Yang HONG

《工程管理前沿（英文）》 2018年第5卷第2期页码 278-283 doi: 10.15302/J-FEM-2018202

关键词： manned space station space station project basic design

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Application and development of modern long-span space structures in China

Shilin DONG, Yang ZHAO, Dong XING

《结构与土木工程前沿（英文）》 2012年第6卷第3期页码 224-239 doi: 10.1007/s11709-012-0166-6

摘要： Modern long-span space structures, developed during the 1970s and 1980s, are light and effective structures based on new technologies and light-weight high-strength materials, such as membranes and steel cables. These structures include air-supported membrane structures, cable-membrane structures, cable truss structures, beam string structures, suspen-domes, cable domes, composite structures of cable dome and single-layer lattice shell, Tensairity structures and so forth. For the premodern space structures widely used since the mid-twentieth century (such as thin shells, space trusses, lattice shells and ordinary cable structures), new space structures have been developed by the combination of different structural forms and materials. The application of prestressing technology and the innovation of structural concepts and configurations are also associated with modern space structures, including composite space trusses, open-web grid structures, polyhedron space frame structures, partial double-layer lattice shells, cable-stayed grid structures, tree-type structures, prestressed segmental steel structures and so forth. This paper provides a review of the structural characteristics and practical applications in China of modern rigid space structures, modern flexible space structures and modern rigid-flexible combined space structures.

关键词： modern long-span space structures rigid space structures flexible space structures rigid-flexible combined space structures application and development

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统筹空间科学、空间技术、空间应用协调发展的思考

周建平,吴季

《中国工程科学》 2023年第25卷第2期页码 59-66 doi: 10.15302/J-SSCAE-2023.02.007

摘要：

我国航天事业因历史原因和投入限制，在初期以空间技术、空间应用为主，对空间科学重视不足，空间科学、空间技术、空间应用基本上是独立发展的；着眼新时期航天强国建设，需要将空间技术的发展深度融合到空间科学、空间应用中去，从而创造新的机遇和成就。本文剖析了空间科学、空间技术、空间应用的基本内涵并明确三者的相互关系，在系统分析国际空间科学、空间技术、空间应用的整体态势，细致梳理我国相关领域发展情况的基础上，论证了统筹我国空间科学、空间技术、空间应用协调发展的必要性，凝练了三者协调发展面临的主要问题。空间科学、空间技术、空间应用之间既有需求交叉，又可互促带动，应在规划、部署、实施的全过程中进行统筹考虑：发挥新型举国体制优势，在统一管理下做好顶层规划；坚持创新驱动发展战略，以技术进步抢占国际航天制高点；支持空间领域基础研究，培育高水平的科学家和工程师队伍；加强资源统筹协调，促进空间应用数据的合理开放和充分利用。

关键词：航天事业；空间科学；空间技术；空间应用；协调发展；数据开放共享

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空间物理和空间天气探测与研究

王赤

《中国工程科学》 2008年第10卷第6期页码 41-45

摘要：

空间物理学是1957年人造卫星发射成功后迅速发展起来的一门交叉学科。近50年来，空间已成为人类生存的第四环境，其重要性日益突出。20世纪90年代初，空间物理学与空间应用的密切结合产生了专门研究和预报空间环境中灾害性过程及其变化规律，减轻或防止空间灾害并为人类活动服务的空间天气学。文章简要总结了国外及国内空间物理和空间天气探测的历程和发展趋势，并提出对我国未来空间物理和空间天气探测发展规划和探测路线图的几点建议。

关键词：空间物理空间天气空间物理探测发展规划

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基于碳纳米管场效应管的新型三元半加器及乘法器 Article

Sepehr TABRIZCHI,Nooshin AZIMI,Keivan NAVI

《信息与电子工程前沿（英文）》 2017年第18卷第3期页码 423-433 doi: 10.1631/FITEE.1500366

摘要：多值逻辑（multiple-valued logic, MVL），例如三元逻辑，在近年来是大量研究项目的研究对象。MVL可以降低必要操作的数目、减小芯片面积。碳纳米管场效应管（CNTFETs）被认为是硅晶体管可行的替代方案。将CNTFETs与MVL结合，可以得到更快、更灵活的独特设计方案。本文利用微纳技术和三元逻辑设计出了新型的半加器和乘法器。微纳技术和三元逻辑的采纳降低了元件功耗和面积，提升了元件运行速度。我们利用斯坦福CNTFET模型和HSPICE软件对本文设计器件进行了仿真，并将仿真结果与相关研究结果进行了对比。

关键词：碳纳米管场效应管设计；三元；半加器；乘法器；多值逻辑

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深空安全研究现状与未来发展

吴克,张哲,杨文飞,何建峰,张天柱,简抗抗,吴伟仁

《中国工程科学》 2022年第24卷第4期页码 240-248 doi: 10.15302/J-SSCAE-2022.04.023

摘要： Managing space radiation risk in the new era of space exploration [R].Managing space radiation risk in the new era of space exploration [R].Human space exploration the next fifty years [J].Human space exploration the next fifty years [J].Human space exploration the next fifty years [J].

关键词：深空安全空间辐射威胁行星保护太空遗产保护空间立法

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Promoting Si-graphite composite anodes with SWCNT additives for half and NCM811 full lithium ion batteries

Jingning SHAN, Xiaofang YANG, Chao YAN, Yiguang JU, Lin CHEN, Fang ZHAO

《能源前沿（英文）》 2019年第13卷第4期页码 626-635 doi: 10.1007/s11708-019-0650-y

摘要： Single wall carbon nanotube (SWCNT) additives were formulated into µm-Si-graphite composite electrodes and tested in both half cells and full cells with high nickel cathodes. The critical role of small amount of SWCNT addition (0.2 wt%) was found for significantly improving delithiation capacity, first cycle coulombic efficiency (FCE), and capacity retention. Particularly, Si (10 wt%)-graphite electrode exhibits 560 mAh/g delithiation capacity and 92% FCE at 0.2 C during the first charge-discharge cycle, and 91% capacity retention after 50 cycles (0.5 C) in a half cell. Scanning electron microscope (SEM) was used to illustrate the electrode morphology, compositions and promoting function of the SWCNT additives. In addition, full cells assembled with high nickel-NCM811 cathodes and µm-Si-graphite composite anodes were evaluated for the consistence between half and full cell performance, and the consideration for potential commercial application. Finally, criteria to assess Si-containing anodes are proposed and discussed from an industrial perspective.

关键词： lithium-ion battery Si anode Si-graphite composite single wall carbon nanotube (SWCNT) NCM811

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On subsurface box-shaped lined tunnel under incident SH-wave propagation

《结构与土木工程前沿（英文）》 2021年第15卷第4期页码 948-960 doi: 10.1007/s11709-021-0740-x

摘要： In this paper, a half-plane time-domain boundary element method is applied to obtain the seismic ground response, including a subsurface box-shaped lined tunnel deployed in a linear homogenous elastic medium exposed to obliquely incident SH-waves. Only the boundary around the tunnel is required to be discretized. To prepare an appropriate model by quadratic elements, a double-node procedure is used to receive dual boundary fields at corners as well as change the direction of the normal vector. After encoding the method in a previously confirmed computer program, a numerical study is carried out to sensitize some effective parameters, including frequency content and incident wave angle for obtaining a surface response. The depth and impedance ratio of the lining are assumed to be unvaried. The responses are illustrated in the time and frequency domains as two/three-dimensional graphs. The results showed that subsurface openings with sharp corners distorted the propagation path of the anti-plane waves to achieve the critical states on the ground surface. The present approach can be proposed to civil engineers for preparing simple underground box-shaped models with angular boundaries.

关键词： box-lined tunnel half-plane BEM surface response SH-wave time-domain

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Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive

《化学科学与工程前沿（英文）》页码 1623-1631 doi: 10.1007/s11705-022-2202-y

摘要： The number of active components and their dispersion degree are two key factors affecting the performance of adsorbents. Here, we report a simple but efficient strategy for dispersing active components by using a confined space, which is formed by mesoporous silica walls and templates in the as-prepared SBA-15 (AS). Such a confined space does not exist in the conventional support, calcined SBA-15, which does not contain a template. The Cu and Zn precursors were introduced to the confined space in the AS and were converted to CuO and ZnO during calcination, during which the template was also removed. The results show that up to 5 mmol·g^–1 of CuO and ZnO can be well dispersed; however, severe aggregation of both oxides takes place in the sample derived from the calcined SBA-15 with the same loading. Confined space in the AS and the strong interactions caused by the abundant hydroxyl groups are responsible for the dispersion of CuO and ZnO. The bimetallic materials were employed for the adsorptive separation of propene and propane. The samples prepared from the as-prepared SBA-15 showed superior performance to their counterparts from the calcined SBA-15 in terms of both adsorption capacity of propene and selectivity for propene/propane.

关键词： bimetallic adsorbents confined space mesoporous silica propene/propane separation