检索结果-南通市图书馆

Rubik's cube as in-situ programmable matter and a reconfigurable mechanical metamaterial

Science China Technological Sciences 2024年第10期67卷 3221-3234页

作者： ZHU ShaoWei CHEN Huan YANG XiaoQiang tan Li JIN Shuai CHEN LiMing LIU Tao tan xiaojun WANG LianChao WANG Bing MUAMER Kadic College of Aerospace Engineering Chongqing University State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University School of Civil Aviation Northwestern Polytechnical University National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Institut FEMTO-ST CNRS UMR 6174University Bourgogne

As part of the 4th industrial revolution, programmable mechanical metamaterials exhibit great application potential in flexible robotics, vibration control, and impact protection. However, maintaining a programmed state without sustaining the external stimulus is often challenging and leads to additional energy consumption. Inspired by Rubik's cube, we design and study an insitu programmable and distribution-reconfigurable mechanical metamaterial(IPDR-MM). A matrix model is developed to model IPDR-MMs and describe their morphological transitions. Based on this model, the reinforcement learning method is employed to find the pathways for morphological transitions. We find that IPDR-MMs have controllable stiffness across several orders of magnitude and a wide range of adjustable anisotropies through morphology transformation. Additionally, because of the independence of the directions of morphology transformation and bearing, IPDR-MMs exhibit good stability in bearing and can readily achieve high stiffness. The Rubik's cube-inspired design concept is also instructive for other deformable structures and metamaterials, and the current version of the proposal should be sufficiently illustrative to attract and broaden interdisciplinary interests.

关键词： mechanical metamaterials in-situprogrammable distribution-reconfigurable Rubik's cube controllable stiffness and anisotropy

来源：

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

冰球和钨珠非正冲击下T800-CFRP层合板损伤特性的研究

引用

振动与冲击 2024年第11期43卷 135-147页

作者：尚晓壮刘瑶璐冯晓伟胡宁谭晓军胡艳辉重庆大学航空航天学院重庆400044 重庆大学非均质材料力学重庆市重点实验室重庆400044 中国工程物理研究院总体工程研究所四川绵阳621900 河北工业大学机械工程学院天津300401

通过试验和仿真相结合的方法研究了T800碳纤维增强复合材料(CFRP)层合板在冰球和钨珠非正冲击作用下的损伤特性。首先开展了冰球和钨珠在给定工况下高速撞击T800-CFRP层合板试验,以此对仿真模型的有效性进行验证;然后讨论了T800-CFRP层... 详细信息

通过试验和仿真相结合的方法研究了T800碳纤维增强复合材料(CFRP)层合板在冰球和钨珠非正冲击作用下的损伤特性。首先开展了冰球和钨珠在给定工况下高速撞击T800-CFRP层合板试验,以此对仿真模型的有效性进行验证;然后讨论了T800-CFRP层合板在两种冲击体以不同冲击能量与冲击角度作用下的损伤特性及其差异性。研究表明:钨珠在冲击能量较低时就能对层合板造成穿孔损伤,但随着冲击能量增大层合板的损伤程度呈下降趋势;冰球对层合板造成损伤的冲击能量阈值与钨珠的相比要高很多,且随着冲击能量的增加损伤程度明显加剧;钨珠在冲击角度为45°和60°时造成的损伤与正冲击的情况相比要更加严重,而冲击角度为30°时造成的损伤却小于正冲击的情况;冰球冲击时,层合板的损伤程度随冲击角度的增加而减小。该研究有助于深化对T800-CFRP层合板在冲击载荷作用下的损伤与破坏行为的认识,具有重要的科学意义和工程应用价值。

关键词： T800碳纤维增强复合材料冰球钨珠非正冲击损伤特性

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Graphical representations and worm algorithms for the O(N) spin model

引用

Communications in Theoretical Physics 2023年第11期75卷 152-161页

作者： Longxiang Liu Lei Zhang xiaojun tan Youjin Deng Simulation of Physical Systems Division Beijing Computational Science Research CenterBeijing 100193China National Laboratory for Physical Sciences at Microscale University of Science and Technology of ChinaHefeiAnhui 230026China Department of Modern Physics University of Science and Technology of ChinaHefeiAnhui 230026China

We present a family of graphical representations for the O(N)spin model,where N≥1 represents the spin dimension,and N=1,2,3 corresponds to the Ising,XY and Heisenberg models,*** an integer parameter 0≤ℓ≤N/2,each configuration is the coupling of ℓ copies of subgraphs consisting of directed flows and N−2ℓ copies of subgraphs constructed by undirected loops,which we call the XY and Ising subgraphs,*** each lattice site,the XY subgraphs satisfy the Kirchhoff flow-conservation law and the Ising subgraphs obey the Eulerian bond ***,we formulate worm-type algorithms and simulate the O(N)model on the simple-cubic lattice for N from 2 to 6 at all possibleℓ.It is observed that the worm algorithm has much higher efficiency than the Metropolis method,and,for a given N,the efficiency is an increasing function ofℓ.Besides Monte Carlo simulations,we expect that these graphical representations would provide a convenient basis for the study of the O(N)spin model by other state-of-the-art methods like the tensor network renormalization.

关键词： Markov-chain Monte Carlo algorithms continuous spin models graphical representations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

碳化硅陶瓷超快激光双光束精密抛光技术研究

引用

激光技术 2024年第2期48卷 180-187页

作者：肖海兵张庆茂谭小军周泳全张卫罗博伟深圳信息职业技术学院智能制造与装备学院深圳518172 华南师范大学信息光电子科技学院、广东省微纳光子功能材料与器件重点实验室广州510006

为了有效提高碳化硅陶瓷材料抛光精度,采用了一种红外脉冲和超快紫外皮秒激光双光束抛光碳化硅陶瓷技术。通过红外纳秒激光与超快紫外皮秒激光抛光碳化硅陶瓷材料激光双光束抛光方法,实验研究了激光功率、重复频率、扫描速率、离焦量等... 详细信息

为了有效提高碳化硅陶瓷材料抛光精度,采用了一种红外脉冲和超快紫外皮秒激光双光束抛光碳化硅陶瓷技术。通过红外纳秒激光与超快紫外皮秒激光抛光碳化硅陶瓷材料激光双光束抛光方法,实验研究了激光功率、重复频率、扫描速率、离焦量等抛光工艺参数对抛光SiC表面质量的影响。结果表明,在激光功率24 W、扫描速率200 mm/s、激光重复频率500 kHz、离焦1 mm时,陶瓷表面粗糙度达到最优,激光双光束抛光和单光束抛光原始粗糙度碳化硅2.87μm分别下降至0.42μm和0.53μm;激光双光束抛光SiC陶瓷致密化,陶瓷表面呈现有规律的整齐排列,且碳化硅抛光表面的晶粒平均大小为1.48μm,表面力学性能得到改善。该研究为陶瓷等硬脆材料激光精密抛光提供了参考。

关键词：激光技术激光抛光超快光学激光双光束碳化硅陶瓷表面形貌

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Method for Classification and Evaluation of Pilot’s Mental States Based on CNN

引用

Computer Systems Science & Engineering 2023年第8期46卷 1999-2020页

作者： Qianlei Wang Zaijun Wang Renhe Xiong Xingbin Liao xiaojun tan Chengdu Institute of Computer Application Chinese Academy of SciencesChengdu610041SichuanChina School of Computer Science and Technology University of Chinese Academy of SciencesBeijing 100080China Key Laboratory of Flight Techniques and Flight Safety Civil Aviation Flight University of ChinaGuanghan618307SichuanChina School of Air Traffic Management Civil Aviation Flight University of ChinaGuanghan618307SichuanChina Neurology Department Deyang Second People’s HospitalGuanghan618307SichuanChina

How to accurately recognize the mental state of pilots is a focus in civil aviation *** mental state of pilots is closely related to their cognitive ability in *** the cognitive ability meets the standard is related to flight ***,the pilot’s working state is unique,which increases the difficulty of analyzing the pilot’s mental *** this work,we proposed a Convolutional Neural Network(CNN)that merges attention to classify the mental state of pilots through electroencephalography(EEG).Considering the individual differences in EEG,semi-supervised learning based on improvedK-Means is used in themodel training to improve the generalization ability of the *** collected the EEG data of 12 pilot trainees during the simulated flight and compared the method in this paper with other methods on this *** method in this paper achieved an accuracy of 86.29%,which is better than 4D-aNN and HCNN *** emotion will increase the probability of fatigue appearing,and emotion recognition is also meaningful during the *** we conducted experiments on the public dataset SEED,and our method achieved an accuracy of 93.68%.In addition,we combine multiple parameters to evaluate the results of the classification network on a more detailed level and propose a corresponding scoring mechanism to display the mental state of the pilots directly.

关键词： Pilot mental state EEG attention CNN semi-supervised learning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

THREE DIMENSIONAL DATA STRUCTURE AND DATA MODEL

引用

Geo-Spatial Information Science 2000年第3期3卷 19-23页

作者： Bian Fuling Zhu Guobin Li Jun tan xiaojun School of Inforrmtion Enginaering WTUSM

3D GISs were developed simultaneously in the late 1980s in a number of different *** development of these 3D GISs can not yet meet all needs for new representations and analytical tool s in 3D envir *** this paper,the data structures,especially solid-based data representa tions are ***,a typical object-oriented data model is put forth to s how a new data *** at last,two data access methods are proposed to make th e data model clear.

关键词： 3D data structure data model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Grain size and surface micro-texture characteristics and their paleoenvironmental significance of Holocene sediment in southern margin of the Gurbantunggut Desert,China

引用

Journal of Arid Land 2024年第5期16卷 632-653页

作者： MA Yunqiang LI Zhizhong tan Dianjia ZOU xiaojun TAO Tonglian School of Geographical Sciences Fujian Normal UniversityFuzhou 350117China Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 350117China Institute of Geography Fujian Normal UniversityFuzhou 350117China

The southern margin of the Gurbantunggut Desert,China,is characterized by alternating layers of aeolian and alluvial *** the characteristics of arenaceous sediment in this area is of significant importance for understanding the interactive processes of wind and water forces,as well as the provenance of ***,there are relatively few investigations on the characteristics of such sediment at *** this study,we researched three aeolian-alluvial interactive stratigraphic profiles and different types of surface sediment on the desert-oasis transitional zone of southern margin of the Gurbantunggut *** on the optically stimulated luminescence(OSL)dating of aeolian sand and analyses of quartz sand grain size and surface micro-texture,we explored the aeolian-alluvial environmental change at southern margin of the desert in Holocene,as well as the provenance of *** results indicated that the grain size characteristics of different types of sediment in the stratigraphic profiles were similar to those of modern dune sand,interdune sand,muddy desert surface soil,and riverbed *** frequency curves were unimodal or bimodal,and cumulative probability curves were two-segment or three-segment,mainly composed of suspension load and saltation *** quartz sand in the sediment at southern margin of the desert had undergone alternating transformation of various exogenic forces,with short transportation distance and time,and sedimentary environment was relatively *** Holocene,southern margin of the desert primarily featured braided river deposits,and during intermittent period of river activity,there were also aeolian deposits such as sand sheet deposits,stabilized dune deposits,and mobile dune *** provenance for Holocene alluvial deposits at southern margin of the desert remains relatively constant,with the debris of the Tianshan Mountains being the primary *** sand is mainly near-source recharge,

关键词： aeolian-alluvial deposition grain size surface micro-texture sedimentary environment Holocene

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Au nanospheres modified boron-doped diamond microelectrode grown via hydrogen plasma etching solid doping source for dopamine detection

引用

Journal of Materials Science & Technology 2020年第14期47卷 42-46页

作者： Kaili Yao xiaojun tan Bing Dai Jie Bai Qiaoyang Sun Wenxin Cao Jiwen Zhao Lei Yang Jiecai Han Jiaqi Zhu National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin150080China

Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s *** this work,we developed a new doping source-graphite and solid boron oxide powders to synthesize BDD film with microwave plasma chemical vapor deposition,so as to avoid using toxic or corrosive dopants,such as boroethane and *** synthesized BDD film is pinhole free and with high doping density of 8.44×10^20 cm^-3 calculated from the Raman ***,Au nanospheres were decorated on the surface of BDD film to improve electrochemical performance of the BDD *** Au nanoparticles modified BDD electrode demonstrates an excellent electrochemical response,a high sensitivity(in the range of 5μM-1 m M),and a low detection limit(~0.8μM)for detecting dopamine.

关键词： Boron doped diamond Graphite powders Boron oxide powders Optical emission spectroscopy Dopamine

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

二氧化硅空心球/碳锂离子电池负极材料

引用

山东化工 2024年第15期53卷 24-27,31页

作者：代晓雪史超云赵云浩陈敬波谭晓军贵州大学化学与化工学院贵州贵阳550025 贵州能矿锰业集团有限公司贵州铜仁550004

锂离子电池具有能量密度高、使用寿命长、绿色环保、安全性能良好等优点。二氧化硅具有较高的理论比容量、储量丰富、绿色无污染等特点,是最有前景的锂离子电池负极材料之一。但二氧化硅在脱嵌锂过程中产生的体积效应,使得锂离子电池的... 详细信息

锂离子电池具有能量密度高、使用寿命长、绿色环保、安全性能良好等优点。二氧化硅具有较高的理论比容量、储量丰富、绿色无污染等特点,是最有前景的锂离子电池负极材料之一。但二氧化硅在脱嵌锂过程中产生的体积效应,使得锂离子电池的性能大大降低。为提高锂离子电池的电化学性能,本文制备了二氧化硅/碳(SiO_(2)@C)复合材料,并将其作为锂离子电池负极材料。中空结构有效地缓解了二氧化硅充放电过程中的体积膨胀,提高了复合材料在锂化过程中的结构稳定性。碳层可以作为“缓冲层”,缓解了二氧化硅的体积膨胀,同时碳具有良好的导电性,可以提高复合材料的导电性。在0.1 Ag^(-1)电流密度下经过50次循环后,SiO_(2)@C的放电比容量为766.2 mAhg^(-1),表现出良好的电化学性能。

关键词：二氧化硅中空结构锂离子电池负极材料

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

术前γ-谷氨酰转肽酶对非转移性肾细胞癌预后的影响

引用

西部医学 2024年第5期36卷 749-754页

作者：孙静龙琼先夏中友谭小军王浩吕宸伍季南充市中心医院·川北医学院第二临床医学院泌尿外科四川南充637000 南充市中心医院·川北医学院第二临床医学院病理科四川南充637000

目的评价术前γ-谷氨酰转肽酶(GGT)对非转移性肾细胞癌(nmRCC)患者术后预后的影响。方法收集2013年1月—2018年7月在本院接受根治性肾切除手术或肾部分切除术治疗的118例nmRCC患者的临床资料。按受试者工作特征(ROC)曲线确定GGT最佳临... 详细信息

目的评价术前γ-谷氨酰转肽酶(GGT)对非转移性肾细胞癌(nmRCC)患者术后预后的影响。方法收集2013年1月—2018年7月在本院接受根治性肾切除手术或肾部分切除术治疗的118例nmRCC患者的临床资料。按受试者工作特征(ROC)曲线确定GGT最佳临界值并分为高GGT组和低GGT组,比较两组患者性别、年龄、肿瘤直径等临床资料,运用Kaplan-Meier法进行生存分析,绘制生存曲线,并采用Log-rank法比较各组生存曲线的差异,采用Cox多因素回归分析影响nmRCC患者预后的独立危险因素。结果根据ROC曲线最大约登指数得出GGT最佳截断值为48.5。本研究结果显示,高GGT组的T3-T4分期所占百分比高于低GGT组(38.9%vs 13.0%,P<0.05)和高GGT组的G3-G4分级所占百分比高于低GGT组(33.3%vs 3.0%,P<0.05)。高GGT组总生存期(OS)和无复发生存期(RFS)均低于低GGT组(Log-rank=33.743,P<0.001;Log-rank=30.854,P<0.001)。Cox多因素分析结果表明,肿瘤大小≥4 cm、更高的肿瘤T分期、术前GGT≥48.5和更高的G分级是影响nmRCC患者术后OS和RFS的独立危险因素(P<0.05)。结论nmRCC患者术前高GGT是肿瘤高T分期和高G分级的重要预测指标,同时也是患者术后总生存期和无复发生存期不佳的独立危险因素,能预测其预后。

关键词：肾癌 γ-谷氨酰转肽酶预后独立危险因素

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：