检索结果-内蒙古大学图书馆

Significant impact of TiO2 purity on the phase structure and electrical properties of BiFeO3-BaTiO3 lead-free piezoelectric ceramics

引用

JOURNAL OF THE AMERICAN CERAMIC SOCIETY 2024年第6期107卷 4232-4241页

作者： Chen, Xiaoxin Qin, Hailan Li, Hongtian Du, Yuxiao Wang, Shenghao Li, Peifeng Hu, Yongming Liu, Laijun Zhao, Jianwei Wang, Dawei Guilin Univ Technol Coll Mat Sci & Engn Guilin 541010 Peoples R China Chinese Acad Sci Shenzhen Inst Adv Elect Mat Shenzhen Inst Adv Technol Shenzhen 518055 Peoples R China Hubei Univ Hubei Key Lab Ferro & Piezoelectr Mat & Devices Wuhan Peoples R China Harbin Inst Technol Sch Instrumentat Sci & Engn Harbin 150080 Peoples R China

In many studies, the properties of BiFeO3-BaTiO3 (BF-BT) ceramics vary greatly using different raw reagents, which makes it challenging to obtain reliable and repeatable properties of BF-BT-based devices. In this work, 0.7BiFeO(3)-0.3BaTiO(3) (0.7BF-0.3BT) ceramics were fabricated by a conventional solid-phase synthesis using TiO2 reagents with varied purities of 98%, 99%, 99.9%, and 99.99%, respectively. The phase structure, microstructure, ferroelectric, and piezoelectric properties were comprehensively studied. All compositions of the ceramics exhibit a pseudo-cubic phase perovskite structure, and the fraction of the rhombohedral phase increases with increasing the TiO2 purity. Additionally, backscattered electron images and energy-dispersive spectroscopy revealed an obvious core-shell structure within grains. In particular, the 0.7BF-0.3BT ceramics prepared with 98% purity TiO2 exhibited superior ferroelectric and piezoelectric properties, d(33) similar to 220 pC/N and d(33)(& lowast;) similar to 230 pm/V. The ceramics prepared with higher purity TiO2 suffered from severe leakage conduction, which can be well addressed by adding excess TiO2. Our work reveals the importance of different grades of purity TiO2 on the electrical properties of BF-BT ceramics.

关键词： BiFeO3-BaTiO3 electric properties ferroelectric piezoelectric TiO2 purity

来源：评论

学校读者我要写书评

暂无评论

Challenges and approaches of single-crystal Ni-rich layered cathodes in lithium batteries

引用

National science Review 2023年第12期10卷 203-222页

作者： Jiangtao Hu Hongbin Wang Biwei Xiao Pei Liu Tao Huang Yongliang Li Xiangzhong Ren Qianling Zhang Jianhong Liu Xiaoping Ouyang Xueliang Sun Graphene Composite Research Center College of Chemistry and Environmental EngineeringShenzhen University GRINM(Guangdong) Institute for Advanced Materials and Technology School of Materials Science and Engineering Xiangtan University Department of Mechanical and Materials Engineering University of Western Ontario Eastern Institute for Advanced Study Eastern Institute of Technology

High energy density and high safety are incompatible with each other in a lithium battery, which challenges today's energy storage and power applications. Ni-rich layered transition metal oxides(NMCs) have been identified as the primary cathode candidate for powering next-generation electric vehicles and have been extensively studied in the last two decades, leading to the fast growth of their market share, including both polycrystalline and single-crystal NMC cathodes. Single-crystal NMCs appear to be superior to polycrystalline NMCs, especially at low Ni content(≤60%). However, Ni-rich single-crystal NMC cathodes experience even faster capacity decay than polycrystalline NMC cathodes, rendering them unsuitable for practical application. Accordingly, this work will systematically review the attenuation mechanism of single-crystal NMCs and generate fresh insights into valuable research pathways. This perspective will provide a direction for the development of Ni-rich single-crystal NMC cathodes.

关键词： single-crystal NMC attenuation mechanism modification strategy developing route

来源：评论

学校读者我要写书评

暂无评论

A Slightly Expanded Graphite Anode with High Capacity Enabled By Stable Lithium-Ion/Metal Hybrid Storage

引用

SMALL 2024年第40期20卷 e2403057页

作者： Li, Tong Cao, Yun Song, Qiuchen Peng, Linkai Qin, Xianying Lv, Wei Kang, Feiyu Tsinghua Univ Tsinghua Shenzhen Int Grad Sch Shenzhen 518055 Peoples R China Shenzhen Graphene Innovat Ctr Co Ltd Shenzhen 518107 Peoples R China

Integrating lithium-ion and metal storage mechanisms to improve the capacity of graphite anode holds the potential to boost the energy density of lithium-ion batteries. However, this approach, typically plating lithium metal onto traditional graphite anodes, faces challenges of safety risks of severe lithium dendrite growth and short circuits due to restricted lithium metal accommodation space and unstable lithium plating in commercial carbonate electrolytes. Herein, a slightly expanded spherical graphite anode is developed with a precisely adjustable expanded structure to accommodate metallic lithium, achieving a well-balanced state of high capacity and stable lithium-ion/metal storage in commercial carbonate electrolytes. This structure also enables fast kinetics of both Li intercalation/de-intercalation and plating/stripping. With a total anode capacity of 1.5 times higher (558 mAh g(-1)) than graphite, the full cell coupled with a high-loading LiNi0.8Co0.1Mn0.1O2 cathode (13 mg cm(-2)) under a low N/P ratio (similar to 1.15) achieves long-term cycling stability (75% of capacity after 200 cycles, in contrast to the fast battery failure after 50 cycles with spherical graphite anode). Furthermore, the capacity of the full cell also reaches a low capacity decay rate of 0.05% per cycle at 0.2 C under the low temperature of -20 degrees C.

关键词： expansion graphite hybrid anode lithium metal

来源：评论

学校读者我要写书评

暂无评论

Long-term evolutionary patterns matter: Self-supervised anomaly detection on dynamic graphs

引用

KNOWLEDGE-BASED SYSTEMS 2025年 311卷

作者： Fu, Yun Zhou, Che Li, Jintang Chen, Liang Sun Yat Sen Univ Sch Comp Sci & Engn Guangzhou Peoples R China Sun Yat Sen Univ Sch Software Engn Zhuhai Peoples R China

Graph anomaly detection (GAD) plays a crucial role in identifying anomalous individuals (e.g., nodes or edges) whose behaviors or patterns deviate significantly from the normal majority within a graph. Recent years have witnessed breakthrough advancements in research on static graphs. However, the GAD problem becomes more challenging when switching from static graphs to dynamic graphs due to the temporal evolution of graph structures and the scarcity of anomaly labels. Although various approaches have been proposed to address these challenges, they often struggle to capture the evolving dynamics and neglect the potential of capturing nodes' smooth long-term evolutionary patterns for self-supervised anomaly detection in dynamic graph. In this work, we empirically demonstrate that normal nodes exhibit smooth long-term evolutionary patterns, while anomalous nodes deviate significantly from their long-term histories. Motivated by this observation, we propose a multi-step histories-based contrastive learning framework, MHisCL, to detect anomalies in dynamic graphs in a self-supervised manner. Specifically, we treat a node's current state and its multi-step historical states as a positive contrastive pair, encouraging alignment between them to capture the smooth long-term evolutionary patterns of normal nodes. Consequently, MHisCL is capable of efficiently detecting anomalies by measuring the disagreement of nodes' positive pairs through a simple similarity computation. Furthermore, to better capture complex evolving dynamics, MHisCL incorporates a novel state space time encoding (SSTE), which explicitly models the temporal evolution of node representations through a linear dynamical system. We evaluate MHisCL on several dynamic graph benchmarks, and it outperforms state-of-the-art baseline by large margins.

关键词： Anomaly detection Dynamic graphs Contrastive learning

来源：评论

学校读者我要写书评

暂无评论

CAGAN: Constrained neural architecture search for GANs

引用

KNOWLEDGE-BASED SYSTEMS 2024年 302卷

作者： Yang, Yeming Zhang, Xinzhi Zhu, Qingling Chen, Weineng Wong, Ka-Chun Lin, Qiuzhen Shenzhen Univ Coll Comp Sci & Software Engn Shenzhen Peoples R China Shenzhen Univ Natl Engn Lab Big Data Syst Comp Technol Shenzhen Peoples R China South China Univ Technol Sch Comp Guangzhou Peoples R China City Univ Hong Kong Dept Comp Sci Hong Kong Peoples R China

Recently, a number of Neural Architecture Search (NAS) methods have been proposed to automate the design of Generative Adversarial Networks (GANs). However, due to the unstable training of GANs and the multi- model forgetting of one-shot NAS, the stability of embedding NAS into GANs is still not satisfactory. Thus, we propose a constrained evolutionary NAS method for GANs (called CAGAN) and design a first benchmark (NAS-GAN-Bench-101) for NAS in GANs. First, we constrain the sampling architecture size to steer the evolutionary search towards more promising and lightweight architectures. Subsequently, we propose a shape- constrained sampling strategy to select more reasonable architectures. Moreover, we present a multi-objective decomposition selection strategy to simultaneously consider the model shape, Inception Score (IS), and Fr & eacute;chet Inception Distance (FID), which produces diverse superior generator candidates. CAGAN has been applied to unconditioned image generation tasks, in which the evolutionary search of GANs on the CIFAR-10 is completed in 0.35 GPU days. Our searched GANs showed promising results on the CIFAR-10 with (IS = 8.96 +/- 0.06, FID = 9.45) and surpassed previous NAS-designed GANs on the STL-10 with (IS = 10.39 +/- 0.13, FID = 19.34). Our source codes are available at https://***/fly2tortoise/CAGAN.

关键词： Generative Adversarial Network Neural Architecture Search Evolutionary Algorithm

来源：评论

学校读者我要写书评

暂无评论

Blue-Emitting Iridium(III) Carbene Phosphors with Suppressed Efficiency Roll-Off and Enhanced Durability of Hyper-OLED Devices

引用

ADVANCED OPTICAL MATERIALS 2025年第4期13卷

作者： Yan, Jie Wu, Chengcheng Yiu, Shek-Man Kuhn, Martin Huang, Manli Zhang, Youming Zhou, Xiuwen Yang, Chuluo Wei, Guodan Chi, Yun City Univ Hong Kong Dept Mat Sci & Engn Dept Chem Kowloon Hong Kong 999077 Peoples R China City Univ Hong Kong Ctr Superdiamond & Adv Films COSDAF Hong Kong 999077 Peoples R China Tsinghua Univ Inst Mat Res Shenzhen 518055 Peoples R China Univ Queensland Sch Math & Phys Brisbane Qld 4072 Australia Shenzhen Univ Coll Mat Sci & Engn Shenzhen Key Lab New Informat Display & Storage Ma Shenzhen 518055 Peoples R China Queensland Univ Technol Sch Chem & Phys Brisbane Qld 4000 Australia

OLED technology has been long hampered by the slow progress of efficient and durable blue phosphors. To circumvent this issue, a novel imidazo[4,5-b]pyrazin-2-ylidene chelate with both the bulky tert-butyl and 2,6-dimethylphenyl appendages is rationally employed in synthesizing Ir(III) carbene phosphors f-ct8c and f-ct8d. Installation of bulky groups at the proper location not only reduces the anticipated product isomers to two, but also improves the photophysical efficiency of these Ir(III) emitters. Notably, these emitters exhibited blue photoluminescence with excellent quantum yields and short radiative lifetimes. One device with assistant sensitizer f-ct8c at 10 wt% and terminal emitter nu-DABNA at 1 wt% has successfully achieved a remarkable EQEmax of 30.5%, CIExy chromaticity of (0.129, 0.079), confirming the generation of exceptional blue hyperphosphorescence. Moreover, the same emitter f-ct8c co-doped in exciplex co-host of SiCzCz: SiTrzCz2 afforded EQEmax of 28.4% and EQE of 23.6% at practical luminance of 1000 cd m-2, respectively, together with max. luminance exceeding 27000 cd m-2. A long operational lifetime LT50 of 309 h is obtained for f-ct8d at an initial brightness of 500 cd m-2, affirming the improved efficiency and stability of the molecular designs.

关键词： carbene F & ouml rster resonance energy transfer iridium organic light emitting diodes phosphorescence

来源：评论

学校读者我要写书评

暂无评论

Understanding the determinants of member participation intentions in web-based time banking platforms: role of perceived trust and perceived risk

引用

BEHAVIOUR & INFORMATION technology 2024年

作者： Jiao, Huifang Lin, Meiyan Ma, Lijun He, Mei Guo, Caixuan Shenzhen Inst Informat Technol Sch Management Shenzhen Peoples R China Shenzhen Univ Coll Management Shenzhen Peoples R China Shenzhen Univ Coll Management Room A310Mingli BldgLihu Campus1066 Xueyuan Ave Shenzhen 518055 Guangdong Peoples R China Shenzhen Univ Inst Big Data Intelligent Management & Decis Room A310Mingli BldgLihu Campus1066 Xueyuan Ave Shenzhen 518055 Guangdong Peoples R China

Time banking is a feasible solution to alleviate pension pressure;however, a low user participation rate hinders its development. This research centres the factors affecting the intention to participate in web-based time banking. Drawing on stimulus-organism-response framework, the authors develop and test a model that explains how technological support and institutional support influence behavioural intention, mediated by perceived trust and perceived risk. An online survey was conducted on the members of 'Nansha Time Bank' in China, 315 valid responses were received and analysed. PLS-SEM was applied to check the effects of those factors with the intention of the members. Outcomes suggest that perceived trust is significantly and positively related to member's intention to participate, and perceived risk is negatively related to member's intention to participate. Website quality of the platform can significantly increase perceived trust and reduce perceived risk. However, transaction convenience of the platform is found only to have a negative effect on perceived risk. Finally, government support and sense of community are positively related to perceived trust and negatively associated with perceived risk. The results of this study provide knowledge about members' pattern of participating in time banking and implications for better organisation of those web-based time banks.

关键词： Time banking perceived trust perceived risk behavioural intention

来源：评论

学校读者我要写书评

暂无评论

2D Semantic-Guided Semantic Scene Completion

引用

INTERNATIONAL JOURNAL OF COMPUTER VISION 2025年第3期133卷 1306-1325页

作者： Liu, Xianzhu Xie, Haozhe Zhang, Shengping Yao, Hongxun Ji, Rongrong Nie, Liqiang Tao, Dacheng Harbin Inst Technol Weihai Peoples R China Nanyang Technol Univ Nanyang Singapore Harbin Inst Technol Harbin Peoples R China Xiamen Univ Xiamen Peoples R China Harbin Inst Technol Shenzhen Peoples R China

Semantic scene completion (SSC) aims to simultaneously perform scene completion (SC) and predict semantic categories of a 3D scene from a single depth and/or RGB image. Most existing SSC methods struggle to handle complex regions with multiple objects close to each other, especially for objects with reflective or dark surfaces. This primarily stems from two challenges: (1) the loss of geometric information due to the unreliability of depth values from sensors, and (2) the potential for semantic confusion when simultaneously predicting 3D shapes and semantic labels. To address these problems, we propose a Semantic-guided Semantic Scene Completion framework, dubbed SG-SSC, which involves Semantic-guided Fusion (SGF) and Volume-guided Semantic Predictor (VGSP). Guided by 2D semantic segmentation maps, SGF adaptively fuses RGB and depth features to compensate for the missing geometric information caused by the missing values in depth images, thus performing more robustly to unreliable depth information. VGSP exploits the mutual benefit between SC and SSC tasks, making SSC more focused on predicting the categories of voxels with high occupancy probabilities and also allowing SC to utilize semantic priors to better predict voxel occupancy. Experimental results show that SG-SSC outperforms existing state-of-the-art methods on the NYU, NYUCAD, and SemanticKITTI datasets. Models and code are available at https://***/aipixel/SG-SSC.

关键词： Semantic scene completion RGB-D images Semantic-guided fusion Volume-guided semantic predictor

来源：评论

学校读者我要写书评

暂无评论

High-power pulsed Raman fiber laser with wavelength over 2.4 μm

引用

OPTICS AND LASER technology 2025年 182卷

作者： Wang, Meng Ouyang, Deqin Chen, Yewang Liu, Minqiu Zhao, Junqing Zheng, Zhijian Li, Chunbo Ruan, Shuangchen Shenzhen Inst Informat Technol Coll Intelligent Mfg & Equipment Shenzhen 518118 Peoples R China Shenzhen Technol Univ Guangdong Higher Educ Inst Key Lab Adv Opt Precis Mfg Technol Shenzhen 518118 Peoples R China

In this paper, the compact high-power pulsed Raman fiber lasers based on single-pass stimulated Raman scattering have been experimentally presented. Home-built noise-like pulse laser centered at-1994.7 nm with an envelope width of-20.8 ns was utilized as the pump laser, which can provide a maximal output power of-19.1 W without a notable spectral broadening. The 1st-order Raman laser operated at-2190.8 nm with a maximal output power of-4.11 Wand a spectral purity of-93 % was achieved. Furthermore, by finely optimizing the length of Raman-gain fiber, the 2nd-order Raman laser centered at-2408.5 nm with a maximal power of-2.36 W was achieved, which represents the maximal value of Raman laser at 2.4 mu m in silica-core fiber, to the best of our knowledge. The high-power pulsed Raman fiber lasers may have the potential applications in polymer material processing and spectroscopy.

关键词： Stimulated Raman scattering

来源：评论

学校读者我要写书评

暂无评论

Dynamics of pulsating solitons with chaotic behaviors from a 1.7 μ m ultrafast fiber laser

引用

CHAOS SOLITONS & FRACTALS 2024年 187卷

作者： Ji, Yubo Yang, Yatao Song, Yufeng Wang, Ke Du, Geguo Liu, Jun Tang, Dingyuan Wang, Zhenhong Shenzhen Univ Coll Elect & Informat Engn Shenzhen 518060 Peoples R China Shenzhen Technol Univ Future Technol Sch Shenzhen 518118 Peoples R China

We demonstrate observation and dynamics of unique soliton pulsation regime in an ultrafast fiber laser at 1.7 mu m. It is found that with either single-soliton pulse or multiple-soliton pulses in cavity the laser emission could exhibit periodic intensity and shot-to-shot spectra variations as measured based on the dispersive Fourier transformation (DFT) technique. Further, detailed studies turned out that the soliton pulsation can comprise numerous small pulses with random intensities, exhibiting chaotic characteristics. Besides, all the pulses within the multiple solitons possess identical pulsation period. In addition, despite of the fact that the temporal intervals between the multiple solitons are on the order of tens of nanoseconds among them, their pulsations demonstrate excellent synchronicity. The experimental observations are further revealed by numerical simulations. These results can provide insights into ways to optimize designs of laser sources and open up new potential for generation of pulsating solitons in ultrafast fiber lasers at different wavelengths.

关键词： Ultrafast fiber lasers 1.7 mu m Pulsating solitons Soliton dynamics

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：