检索结果-南通市图书馆

Catalyst-free and Reprocessable Aromatic Polydithiourethanes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第10期42卷 1435-1441页

作者： Bo Yang Hai-jun Feng Tian-Tian Ni Xiao-Rui Zhou tao Xie Ning Zheng State Key Laboratory of Chemical Engineering College of Chemical and Biological Engineering Zhejiang University Department of Colorectal Surgery and Oncology Key Laboratory of Cancer Prevention and Intervention Ministry of Education The Second Affiliated HospitalZhejiang University School of Medicine

The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks, thereby meeting the sustainable requirements for polymer recycling. However, the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing conditions. In this work, we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst, enabling the efficient reprocessing of the corresponding *** a consequence, the mechanical properties of the polydithiourethane can be largely preserved after reprocessing. The discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.

关键词： Dynamic covalent bond Polydithiourethane Reprocessing

Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 composites prepared by an in-situ synthesis method

在线全文

学校读者我要写书评

暂无评论

China Foundry 2024年第2期21卷 168-174页

作者： Zhi-yong Zhang jiao-jiao Cheng jia-qi Xie Shi-bing Liu Kun Shi jun Zhao Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high *** this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting *** characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were *** revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and ***,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like *** increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature ***,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

关键词： titanium matrix composites microstucture microhardness tensile properties in-situ synthesis

Optimizing near-carbon-free nuclear energy systems:advances in reactor operation digital twin through hybrid machine learning algorithms for parameter identification and state estimation

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第8期35卷 177-203页

作者： Li‑Zhan Hong He‑Lin Gong Hong‑jun Ji jia‑Liang Lu Han Li Qing Li Paris Elite Institute of Technology Shanghai Jiao Tong UniversityShanghai 200240China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610041China

Accurate and efficient online parameter identification and state estimation are crucial for leveraging digital twin simulations to optimize the operation of near-carbon-free nuclear energy *** previous studies,we developed a reactor operation digital twin(RODT).However,non-differentiabilities and discontinuities arise when employing machine learning-based surrogate forward models,challenging traditional gradient-based inverse methods and their *** study investigated deterministic and metaheuristic algorithms and developed hybrid algorithms to address these *** efficient modular RODT software framework that incorporates these methods into its post-evaluation module is presented for comprehensive *** methods were rigorously assessed based on convergence profiles,stability with respect to noise,and computational *** numerical results show that the hybrid KNNLHS algorithm excels in real-time online applications,balancing accuracy and efficiency with a prediction error rate of only 1%and processing times of less than 0.1 ***,algorithms such as FSA,DE,and ADE,although slightly slower(approximately 1 s),demonstrated higher accuracy with a 0.3%relative L_2 error,which advances RODT methodologies to harness machine learning and system modeling for improved reactor monitoring,systematic diagnosis of off-normal events,and lifetime management *** developed modular software and novel optimization methods presented offer pathways to realize the full potential of RODT for transforming energy engineering practices.

关键词： Parameter identification State estimation Reactor operation digital twin Reduced order model Inverse problem

Changes in microstructure and properties of weld heat-affected zone of high-strength low-alloy steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第8期31卷 2041-2052页

作者： Shu-jun jia Qi-lin Ma Yu Hou Ba Li He-song Zhang Qing-you Liu Central Iron and Steel Research Institute Co. Ltd.Beijing 100081China Collaborative Innovation Center for Steel Commonality University of Science and Technology BeijingBeijing 100083China Construction Project Management Branch of China National Petroleum Pipeline Network Group Co. Ltd.Langfang 065000HebeiChina

The evolution of the microstructure and toughness of APL5L X80 pipeline steel after thermal welding simulation was investigated by X-ray diffraction,electron backscatter diffraction,and transmission electron *** results indicated that primary heat-affected zones can be divided into weld,coarse-grained,fine-grained,intercritical,and sub-critical *** microstructure of the weld zone is mainly composed of bainitic ferrite and a small amount of granular bainite;however,the original austenite grains are distributed in the columnar *** structure of the coarse-grained zone is similar to that of the weld zone,but the original austenite grains are *** contrast,the microstructure in the fine-grained zone is dominated by fine granular bainite,and the effective grain size is only 8.15μm,thus providing the highest toughness in the entire heat-affected *** intercritical and subcritical zones were brittle valley regions,and the microstructure was dominated by granular ***,the martensite-austenite(M/A)constituents are present in island chains along the grain boundaries,and the coarse size of the M/A constituents seriously reduces the *** results of the crack propagation analyzes revealed that high-angle grain boundaries can significantly slow down crack growth and change the crack direction,thereby increasing the material *** impact toughness of the low-temperature tempering zone was equivalent to that of the columnar grain zone,and the impact toughness was between those of the critical and fine-grained zones.

关键词： Welding thermal simulation Impact toughness Crack propagation Martensite-austenite constituent High-strength low-alloy steel weld Heat-affected zone

An origami shield with supporting frame structures optimized by a feature-driven topology optimization method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 447-456页

作者： Dongsheng jia Pengcheng Feng Liangdi Wang Longcan Chen jun Wang Jihong Zhu Yingjie Xu Weihong Zhang State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi'an710072China

In this paper,the design,manufacture and testing of an origami protective shield with a supporting frame structure are *** consists of an origami shield surface and a deployable supporting frame structure that needs to be portable and sufficiently ***,for the design of the shield surface,a threestage origami crease pattern is developed to reduce the shield size in the folded *** shield surface consists of several stiff modular panels and layered with flexible *** modular panels are made of a multi-layer composite where a ceramic layer is made of small pieces to improve durability as those small pieces enable restriction of crack ***,the supporting frame structure is designed as a chain-of-bars structure in order to fold into a highly compact state as a bundle of bars and deploy in ***,a feature-driven topology structural optimization method preserving component sequence is developed where the inter-dependence of sub-structures is taken into account.A bar with semi-circular ends is used as a basic design *** positions of the bar’s end points are treated as design variables and the width of the bars is kept ***,a constraint on the total length of the chain of bars is ***,the modular panels made of multi-layer composite and the full-scale prototype of the origami shield are fabricated and tested to verify the bullet-proof performance.

关键词： Origami Deployable structure Structure design Shield Composite materials

Magnetic nanoparticle-modified hollow double-shell SiC@C@FeCo with excellent electromagnetic wave absorption

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 3164-3174页

作者： Guiyu Peng Jintang Zhou jiaqi tao Weize Wang jun Liu junru Yao Yijie Liu Zhengjun Yao College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211100China Key Laboratory of Material Preparation and Protection for Harsh Environment(Nanjing University of Aeronautics and Astronautics) Ministry of Industry and Information TechnologyNanjing 211100China

Integrated micro and nanostructures,heterogeneous components,defects,and interfaces is the way to develop high-performance microwave absorbing ***,there still needs to be more precise experimental routes and effective *** this work,by a continuous process of vacuum sintering,hydrothermal,and carbon thermal reduction,magnetic FeCo nanoparticles were successfully embedded on the hollow double-shell mesoporous SiC@C surface,thus solving the challenges of a single component loss *** hollow double-shell nanostructure introduces air to enhance impedance matching while significantly reducing the density of the *** extensive defects and heterogeneous grain boundaries effectively enhance the polarization loss *** magnetic loss mechanism introduced by the magnetic particles effectively improves the impedance matching properties of the *** synergy of these multiple advantages has enabled the SCFC_(2)-8(here SiC@C@FeCo is abbreviated to SCFC,2 represents the initial metal ion content,and 8 represents the hydrothermal time)sample to achieve an adequate absorption bandwidth of 6.09 GHz at 2.0 *** a minimum reflection loss of-60.56 dB,the absorption bandwidth can cover the entire C,X,and Ku bands by adjusting the matching thickness(1.3–4.0 mm).This work provides a valuable paradigm for the deeper exploitation of microwave absorption potential and guides the development of other high-performance materials.

关键词： SiC@C@FeCo(SCFC)composites core–shell hollow structure microwave absorption

Study of the reaction mechanism for preparing powdered activated coke with SO_(2)adsorption capability via one-step rapid activation method under flue gas atmosphere

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第1期65卷 158-168页

作者： Binxuan Zhou Jingcai Chang jun Li Jinglan Hong tao Wang Liqiang Zhang Ping Zhou Chunyuan Ma School of Environmental Science and Engineering Shandong UniversityQingdao 266237China School of Energy and Power Engineering Shandong UniversityJinan 250061China Weihai Research Institute of Industrial Technology of Shandong University Weihai 264209China

In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is *** indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this *** stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of *** stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as ***,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third *** the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.

关键词： Reaction mechanism Powdered activated coke preparation SO_(2)adsorption One-step rapid activation Flue gas atmosphere

Hydrogel-Assisted Electrokinetics for High-Resolution and Non-invasive Flow Monitoring in Microfluidic Chips

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第6期42卷 571-577页

作者： Na Zhao Yanni Ma Zehua Yu jun Huang Xiangqian Fu tao Qiu Kang Liu MOE Key Laboratory of Hydraulic Machinery Transients School of Power and Mechanical EngineeringWuhan UniversityWuhanHubei430072 China Department of Urology Renmin Hospital of Wuhan UniversityWuhanHubei430072 China Department of Organ Transplantation Renmin Hospital of Wuhan UniversityWuhanHubei430072 China

Convenient non-invasive flow monitoring would facilitate the operation and control in microfluidic chips,but is challenging due to the small space of microchannels and complex operation required in traditional optical *** this work,we propose a novel non-invasive strategy to probe microfluidic flows via streaming potential *** sealing one side of the microchannel with a piece of hydrogel film,streaming potential inside the channel can be clearly detected by electrodes at outer surface of the hydrogel due to ion diffusion in the *** is detected without sensors contacting with the internal ***,the electrodes shape like a tiny probe,which can move around mapping the flow distribution in a chip with the spatial resolution of 1 mm and flow rate detection limit of 3μL·min–*** inside the channels can also be detected,due to the fluctuation of streaming voltage when gas-liquid interface flows through the electrode,showing an easy and potential way for multi-functional flow monitoring in microfluidic chips.

关键词： Microfluidics Hydrogels Electrokinetics Flow monitoring Non-invasive Sensor Charge transport

Identification of an immune-related gene signature for predicting prognosis and immunotherapy efficacy in liver cancer via cell-cell communication

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第11期30卷 1609-1620页

作者： jun-tao Li Hong-Mei Zhang Wei Wang Dong-Qing Wei College of Mathematics and Information Science Henan Normal UniversityXinxiang 453007Henan ProvinceChina College of Computer and Information Engineering Henan Normal UniversityXinxiang 453007Henan ProvinceChina State Key Laboratory of Microbial Metabolism and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China

BACKGROUND Liver cancer is one of the deadliest malignant tumors *** has provided hope to patients with advanced liver cancer,but only a small fraction of patients benefit from this treatment due to individual *** immune-related gene signatures in liver cancer patients not only aids physicians in cancer diagnosis but also offers personalized treatment strategies,thereby improving patient survival *** several methods have been developed to predict the prognosis and immunotherapeutic efficacy in patients with liver cancer,the impact of cell-cell interactions in the tumor microenvir-onment has not been adequately *** To identify immune-related gene signals for predicting liver cancer prognosis and immunotherapy *** Cell grouping and cell-cell communication analysis were performed on single-cell RNA-sequencing data to identify highly active cell groups in immune-related *** active immune cells were identified by intersecting the highly active cell groups with B cells and T *** significantly differentially expressed genes between highly active immune cells and other cells were subsequently selected as features,and a least absolute shrinkage and selection operator(LASSO)regression model was constructed to screen for diagnostic-related *** genes that were selected more than 5 times in 10 LASSO regression experiments were included in a multivariable Cox regression ***,3 genes(stathmin 1,cofilin 1,and C-C chemokine ligand 5)significantly associated with survival were identified and used to construct an immune-related gene *** The immune-related gene signature composed of stathmin 1,cofilin 1,and C-C chemokine ligand 5 was identified through cell-cell *** effectiveness of the identified gene signature was validated based on experi-mental results of predictive immunotherapy response,tumor mutation burden analysis,immune cell infiltrat

关键词： Liver cancer Cell-cell communication Gene signature Prognosis Immunotherapy Single-cell RNA sequencing