摘要：目前超低场磁共振成像(MRI)质量较差,为提升图像信噪比,射频线圈需尽可能贴近成像区域从而提升信噪比。该文采用间接边界元法并从逆问题角度求出线圈流函数分布,再利用线性规划寻找最优线圈结构。为验证超低场MRI诊断颅脑疾病的有效性,采用上述方法,在54 mT下针对大鼠头-脑几何形状设计了双通道射频接收线圈,并对大鼠脑卒中及脑外伤模型进行成像试验研究。试验结果表明,54mTMRI能够检出水肿和血肿病变,且与病理切片或临床3T MRI图像结果相符。同时,通过脑外伤模型7天的追踪观察,54 mT图像中病变的信号演变规律与高场影像一致。针对特定成像对象和非规则布线曲面,该文利用间接边界元逆问题法设计高信噪比射频接收线圈,大鼠模型试验证明超低场磁共振成像技术具有脑卒中与脑外份早期诊断与床旁影像监护潜力与价值。

摘要：建国初期我国修建的重力坝中除黄坛口和三门峡为实体重力坝外,其余都是宽缝重力坝。宽缝重力坝更加适合当时的时代背景,具有散热容易、渗透压力很小和节省混凝土等优点。某宽缝重力坝已运行60余年,根据近年大坝检查结果,坝体存在宽缝空腔积水、坝体裂缝发育且其发展长度及深度较大、溢流坝段溢流面混凝土冲蚀破坏及河床坝段渗漏量较大等问题。本文根据大坝自身现状及宽缝重力坝特点,结合现行规范进行该水电站大坝缺陷及宽缝对结构受力及耐久性影响研究的必要性分析。

摘要：在超低场磁共振成像设备中,铁磁材料(抗涡流板、铁轭等)会对成像目标区域梯度磁场产生影响,并且在梯度线圈,特别是Z方向线圈工作时,这些金属部件中感应的涡流会导致成像伪影。为解决上述问题,该文提出一种针对永磁型超低场磁共振设备的平面抗涡流Z梯度线圈设计方法。首先,对线圈外侧的铁磁材料进行等效简化,将高磁导率的复杂抗涡流板结构(硅钢片压叠而成)简化为均质磁性板结构以减少计算复杂度。然后,提出一种梯度线圈的参数化设计方法,通过对线圈结构进行参数化表达,直接对Z方向梯度线圈的最终绕线结构进行多目标快速优化,同时在线圈外侧设置反向电流绕线控制系统涡流效应。在保证线圈效率(200μT/(m·A))、最大非线性度(小于5%)的前提下,线圈外侧目标平面最大杂散磁场降低了52%。最后,通过有限元仿真与实验验证了模型简化的准确性与所设计Z梯度线圈的抗涡流性能。

摘要：烷氧基硅烷的水解缩合反应是制备含Si-O-Si功能化有机-无机杂化材料的重要基本反应之一,在有机硅工业应用中占据重要地位。深入了解烷氧基硅烷的水解缩合反应机理及反应动力学,对新型硅基材料的设计、合成及性能调控,以及工业生产过程和产品质量控制均具有重要意义。从实验研究和理论研究两个角度出发,对烷氧基硅烷水解缩合反应机理及反应动力学的研究进展进行了综述。其中,实验研究手段包括核磁共振波谱法、傅里叶变换红外光谱法、拉曼光谱法、气相色谱法、气相色谱质谱联用法,理论研究主要采用量子化学理论计算法。

摘要：目的探讨楚漆器造物艺术当代设计转化的思路与发展策略。方法采用文献研究、案例分析等方法,从功能、形式、审美、伦理4个层面,针对目前楚漆器造物艺术在当代设计转化中呈现的问题,进行反思、分析与策略制定。结论楚漆器造物艺术的当代设计转化在目前仍有实用性不强、同质化泛滥、亲体性不足、伦理意识缺乏等问题,其需要在新时代背景下,从融合新技术、再现恢诡浪漫的艺术风格、融汇亲体性图式语言、融入伦理意识4个方面,进行转化设计实践,以提升设计转化产品的实用价值、艺术价值、审美价值及社会价值。通过对楚漆器造物艺术当代设计转化问题的分析和设计策略研究,为楚漆器造物艺术当代设计转化和相关文创产品设计发展提供有价值的理论参考。

摘要：Based on the obtained data of half-lives（t1/2） for 31 polychlorinated biphenyl congeners（PCBs）, 3D quantitative structure-activity relationship（QSAR） pharmacophore was used to establish a 3D QSAR model to predict the t1/2 values of the remaining 178 PCBs, using the structural parameters as independent variables and lgt1/2 values as the dependent variable. Among this process, the whole data set（31 compounds） was divided into a training set（24 compounds） for model generation and a test set（7 compounds） for model validation. Then, the full factor experimental design was used to research the potential second-order interactional effect between different substituent positions, obtaining the final regulation scheme for PCB. At last, a 3D QSAR pharmacophore model was established to validate the reasonable regulation targeting typical PCB with respect to half-lives and thermostability. As a result, the cross-validation correlation coefficient（q2） obtained by the 3D QSAR model was 0.845（〉0.5） and the coefficient of determination（r2） obtained was 0.936（〉0.9）, indicating that the models were robust and predictive. CoMSIA analyses upon steric, electrostatic and hydrophobic fields were 0.7%, 85.9%, and 13.4%, respectively. The electrostatic field was determined to be a primary factor governing the tt/2. From CoMSIA contour maps, tl/2 increased when substi- tuents possessed electropositive groups at the 2＇-, 3-, Y-, 5- and 5＇- positions and electronegative groups at the 3-, 3＇-, 5-, 6- and 6＇- positions, which could increase the PCB stability in transformer insulation oil. Modification of two typical PCB congeners（PCB-77 and PCB-81） showed that the lgtl/2 for three selected modified compounds increased by 13%（average ratio） compared with that of each congener and the thermostability of them were higher, validating the reasonability of the regulatory scheme obtained from the 3D QSAR model. These results are expected to be beneficial in predicting tl/2 values of PCB homologues and d

摘要：近代中国染织设计史上,同章绸庄的凤韶织物图画馆具有重要意义。这是一个从属于绸庄的设计部门,集中了绸庄的设计力量,为旗下的各大生产企业设计纹样,并以统一品牌对外销售。凤韶图画馆留下了大量织物纹样设计档案,对这些设计档案的分析和解读,使我们得以了解民国时期染织企业的设计管理模式、染织设计的艺术风格。

摘要：Significant advancements have been achieved in the field of Single Image Super-Resolution(SISR)through the utilization of Convolutional Neural Networks(CNNs)to attain state-of-the-art *** efforts have explored the incorporation of Transformers to augment network performance in ***,the high computational cost of Transformers makes them less suitable for deployment on lightweight ***,the majority of enhancements for CNNs rely predominantly on small spatial convolutions,thereby neglecting the potential advantages of large kernel *** this paper,the authors propose a Multi-Perception Large Kernel convNet(MPLKN)which delves into the exploration of large kernel ***,the authors have architected a Multi-Perception Large Kernel(MPLK)module aimed at extracting multi-scale features and employ a stepwise feature fusion strategy to seamlessly integrate these *** addition,to enhance the network's capacity for nonlinear spatial information processing,the authors have designed a Spatial-Channel Gated Feed-forward Network(SCGFN)that is capable of adapting to feature interactions across both spatial and channel *** results demonstrate that MPLKN outperforms other lightweight image super-resolution models while maintaining a minimal number of parameters and FLOPs.

摘要：鄂西土家族村落是我国具有代表性的乡村聚落,特殊的地理和人文环境孕育了其独特的地域文化特征。本文以鄂西土家村落代表性的彭家寨村为例,梳理和分析了鄂西村落不同于其他村落的选址特色和房屋营建特点,挖掘了其背后的精神文化内涵,阐述了土家族的风水观念和崇巫思想。

摘要：文化之于城市是精神是灵魂。铜文化之于铜陵,是城市特色化空间建构的灵魂因子。文章从文化之于城市特色空间战略构建的意义出发,阐明铜艺在铜陵区域文化空间建设中的现实价值。继而着重以铜艺设计实践教学为切入点,论述在提倡创新创意设计的时代背景下,综合文化及文化认知能力的培养在未来铜艺设计实践教学改革中的重要意义。