检索结果-南通市图书馆

Spontaneous ignition of corrugated cardboard under dynamic high radiant flux

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

Defence Technology（防务技术） 2024年第10期40卷 65-77页

作者： liu liu Yan Gu Hong Yang Xing Wang Yang Zhou Xiaogan Dai Yong Han Shanggang wen ming Li Congmei Lin Changgen Feng Fei Tang Yushi wen Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026China Institute of Applied Physics and Computational Mathematics China Academy of Engineering PhysicsBeijing 100088China

Understanding the response of solid combustibles under high radiant fluxes is critical in predicting the thermal damage from extreme *** the more moderate radiant fluxes in conventional hydrocarbon fires,extreme events such as strong explosion,concentrated sunlight and directed energy can generate dynamic radiant fluxes at the MW/m^(2) level,creating a unique threat to *** study investigates the pyrolysis and spontaneous ignition behaviors of corrugated cardboard by using both experimental and numerical methods,under 10-cm dynamic high radiant fluxes ranging from 0.2 to 1.25 MW/m^(2) for 10 *** spontaneous ignition process at dynamic high radiant fluxes was recorded and *** ignition modes were found at the critical radiant flux of 0.4 MW/m^(2),namely hot-gas spontaneous ignition and hot-residue piloted *** latter is not the focus of this paper due to its extremely small probability of *** research reveals that the increase in flux intensity induces shorter delay times for both pyrolysis and ignition,lower ignition energy density,along with a corresponding rise in the critical mass flux and surface temperature at ignition *** simulation results are generally aligned with the experimental findings,despite some divergences may be attributed to model simplifications and parameter *** work contributes to a deeper insight into material behavior under extreme radiation,with valuable implications for fire safety and hazard assessment.

关键词： Extreme radiation Fire safety Corrugated cardboard Pyrolysis Ignition temperature

Investigation of Maxima Assumptions in Modelling Tropical Cyclone- Induced Hazards in the South China Sea

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第3期38卷 491-504页

作者： wen Ze-guo WANG Fu-ming WAN Jing YANG Fan School of Civil Engineering Sun Yat-sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Guangdong Academy of Safety Science and Technology Guangzhou 510060China Guangdong Key Laboratory of Oceanic Civil Engineering Guangzhou 510275China Advanced Energy Science and Technology Guangdong Laboratory(Yangjiang Offshore Wind Energy Laboratory) Yangjiang 529500China

The present study aims to examine the suitability of two commonly used assumptions that simplify modelling metoceanconditions for designing offshore wind turbines in the South China Sea (SCS). The first assumption assumes thatjoint N-year extreme wind and wave events can be independently estimated and subsequently combined. The secondone assumes peak wind and waves can be modelled as occurring simultaneously during a tropical cyclone (TC) *** better understand the potential TC activity, a set of 10000 years synthetic TC events are generated. The wind fieldmodel and the Mike 21 spectral wave model are employed to model the TC-induced hazards. Subsequently, theeffect of the assumptions is evaluated by analyzing the peak structural response of both monopile and semisubmersibleoffshore wind turbines during TC events. The results demonstrate that the examined assumptions are generally *** assessing the implications of these assumptions, valuable insights are obtained, which can inform andimprove the modelling of TC-induced hazards in the SCS region.

关键词： tropical cyclone numerical wave modelling hazards offshore wind turbines structural response

Thermodynamic nature of black holes in coexistence region

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-wen Wei Yu-Xiao liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Effect of cooling method on TiN precipitation behavior of high-titanium high-strength steel during solidification

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7期31卷 1692-1703页

作者： Xue-jian Zhang Guang-wei Yang Yong Wan Yong-hong wen Chuan-sheng Tang ming-qi liu Li-jie Tian Key Laboratory of Metallurgical Emission Reduction and Resources Recycling Anhui University of TechnologyMa'anshan 243002AnhuiChina School of Metallurgical Engineering Anhui University of TechnologyMa'anshan 243002AnhuiChina Baosteel Central Research Institute Baoshan Iron and Steel Co.Ltd.Shanghai 201999China

Metallographic microscopy,scanning electron microscopy and TiN growth thermodynamic and kinetic equations were used to investigate the morphology,quantity,and size of TiN in the center of high-titanium high-strength steels under different solidification cooling *** results showed that TiN in the center of the experimental steels mainly existed in three forms:single,composite(Al2O3-TiN),and multi-particle *** began precipitating at around 1497℃(solidification fraction of 0.74).From the end of melting to solidification for 180 s,the cooling rates in the center of the experimental steels for furnace cooling,air cooling,refractory mold cooling,and cast iron mold cooling tended to stabilize at 0.17,0.93,1.65,and 2.15℃/s,*** size of TiN in the center of the experimental steel cooled using furnace cooling was mainly concentrated in the 5-15 pm *** contrast,the size of TiN in the center of the experimental steels cooled using air cooling,refractory mold cooling,and cast iron mold cooling were mainly concentrated in the 1-5 pm *** addition,their density of TiN in the center of the experimental steels is signif-icantly higher than that of the furnace-cooled experimental *** and kinetic precipitation models of TiN established predicted the growth size of TiN in a high-titanium high-strength steel when the solidification cooling rates are not below 0.93℃/s.

关键词： High-titanium steel Cooling method TiN Thermodynamics Kinetics

Experimental Study of Local Scour Around Four Piles Under Different Attack Angles and Gap Ratios

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

China Ocean Engineering 2024年第4期38卷 612-624页

作者： liu ming-ming TANG Guo-qiang JIN Xin GENG Shao-yang School of Architecture and Engineering Liaocheng UniversityLiaocheng 252000China Water-Sediment Regulation and Sand Effective Utilization Special Laboratory of Shandong Provincial Education Department Liaocheng UniversityLiaocheng 252000China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China College of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225China College of Energy Chengdu University of TechnologyChengdu 610059China

In an effort to investigate and quantify the patterns of local scour,researchers embarked on an in-depth study using a systematic experimental *** research focused on the effects of local scour around a set of four piles,each subjected to different hydromechanical *** particular,this study aimed to determine how different attack angles—the angles at which the water flow impinges on the piles,and gap ratios—the ratios of the spacing between the piles to their diameters,influence the extent and nature of scour.A comprehensive series of 35 carefully designed experiments were orchestrated,each designed to dissect the nuances in how the gap ratio and attack angle might contribute to changes in the local scour observed at the base of pile *** these experimental trials,a wealth of local scour data were collected to support the *** data included precise topographic profiles of the sediment bed around the pile groups,as well as detailed scour time histories showing the evolution of scour at strategic feature points throughout the test *** analysis of the experimental data provided interesting *** study revealed that the interplay between the gap ratio and the attack angle had a pronounced influence on the scouring dynamics of the pile *** of the key observations was that the initial phases of scour,particularly within the first hour of water flow exposure,were characterized by a sharp increase in the scour depth occurring immediately in front of the *** this initial rapid development,the scour depth transitioned to a more gradual change *** contrast,the scour topography around the piles continuously *** suggests that sediment displacement and the associated sculpting of the seabed around pile foundations are sustained and progressive processes,altering the underwater landscape over *** results of this empirical investigation have significant implications for the design and constructio

关键词： local scour piles gap ratio attack angle

Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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4期42卷 544-557页

作者： Chi Zhang Rong liu Jing-Yuan liu wen-Wei Jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

Emerging materials and transistors for integrated circuits

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第3期11卷 7-8页

作者： ming liu Lian-Mao Peng Lab of Nanofabrication and Novel Device Integration Institute of Microelectronics Chinese Academy of Sciences Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of Electronics Peking University

The device technology for integrated circuits(ICs) has received a great deal of attention in the past decade since the mainstream silicon-based complementary metal-oxide-semiconductor(CMOS) field-effect transistor(FET) for modern ICs had been encountering development bottlenecks due to the combination of power constraints, physics, cost and fabrication processes.

关键词：

An Approximation Algorithm Based on Seeding Algorithm for Fuzzy k-Means Problem with Penalties

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2024年第2期12卷 387-409页

作者： wen-Zhao liu Min Li School of Mathematics and Statistics Shandong Normal UniversityJinan 250014ShandongChina

As a classic NP-hard problem in machine learning and computational geometry,the k-means problem aims to partition the given dataset into k clusters according to the minimal squared Euclidean *** from k-means problem and most of its variants,fuzzy k-means problem belongs to the soft clustering problem,where each given data point has relationship to every center *** to fuzzy k-means problem,fuzzy k-means problem with penalties allows that some data points need not be clustered instead of being paid *** this paper,we propose an O(αk In k)-approximation algorithm based on seeding algorithm for fuzzy k-means problem with penalties,whereαinvolves the ratio of the maximal penalty value to the minimal ***,we implement numerical experiments to show the effectiveness of our algorithm.

关键词： Approximation algorithm Seeding algorithm Fuzzy k-means problem with penalties

Morphology Study for GeV Emission of Nearby Supernova Remnant G332.5-5.6

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

Research in Astronomy and Astrophysics 2024年第4期24卷 134-140页

作者： ming-Hong Luo Qing-wen Tang Xiu-Rong Mo Department of Physics School of Physics and Materials ScienceNanchang UniversityNanchang 330031China

A spatial template is important to study nearby supernova remnants(SNRs).For SNR G332.5-5.6,we report a Gaussian disk with a radius of about 1°.06 to be a potential good spatial model in the γ-ray *** this new Gaussian disk,its GeV lightcurve shows a significant variability of about seven *** γ-ray observations of this SNR could be explained well either by a leptonic model or a hadronic model,in which a flat spectrum for the ejected electrons/protons is required.

关键词： ISM:supernova remnants gamma rays:ISM