检索结果-南通市图书馆

Geochronological and geochemical constraints on the petrogenesis and geodynamic process of Hemler,Vlinder,and Il'ichev seamount lavas in NW Pacific

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第6期67卷 1856-1871页

作者： Xun WEI Yan ZHANG Xuefa shi Hui ZHANG Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Qingdao Marine Science and Technology CenterQingdao 266237China Shandong Key Laboratory of Deep Sea Mineral Resources Development(Preparatory) Qingdao 266061China

Oceanic intraplate volcanoes with linear age progressions are usually accepted to be derived from melting of an upwelling mantle *** seamount groups in NW Pacific,however,show complex age-distance relationships that are difficult to explain using the classic“mantle plume hypothesis”,and thus their origins are *** this study,we present ^(40)Ar-^(39)Ar age,geochemical,and Sr-Nd-Pb-Hf isotopic data of lavas from Hemler,Vlinder,and Il’ichev seamounts in NW Pacific,to elucidate their petrogenesis and geodynamic *** lavas from Hemler,Vlinder,and Il’ichev seamounts are classified as alkali basalt,basanite/nephelinite,and *** with Mg O>8 wt.%exhibit high contents of CaO,FeO^(T),and TiO_(2),similar to the composition of melts formed from reaction between carbonated eclogite-derived melts and fertile *** lavas have elevated Zr/Hf ratios(40.6-45.2)and negative Zr and Hf anomalies,indicating the presence of a carbonate component in the mantle *** are enriched in incompatible trace elements and have enriched mantle 1(EM1)-like SrNd-Pb-Hf isotopic *** isotopic compositions of Vlinder,Il’ichev basanite,and Hemler lavas in this study are similar to the Rarotonga *** occurring at the same seamount,the Il’ichev alkali basalts display more depleted SrNd-Hf isotopic compositions compared to Il’ichev *** to plate tectonic reconstruction results,the ages of Hemler(100.1 Ma),Vlinder pre-(100.2 Ma)and post-shield(87.5 Ma),and Il’ichev(56.4 Ma)lavas clearly deviate from the Macdonald,Arago,Rarotonga,and Samoa hotspot tracks,indicating that they cannot directly originate from mantle *** propose that in the mid-Cretaceous,when the Pacific plate passed over Rarotonga hotspot,melting of Rarotonga plume formed the Vlinder(main-shield stage),Pako,and Ioah *** Rarotonga(and possibly Samoa)plume materials would have been dispersed into the surrounding asthenosphere by mantle conve

关键词： Mantle plume Magellan seamount trail Carbonated mantle component Hotspot Lithosphere extension

同方期刊数据库

Experimental investigation on the origin of carbonaceous materials in the fault zone of the Wenchuan earthquake

在线全文

学校读者我要写书评

暂无评论

Earthquake Science 2024年第3期37卷 189-199页

作者： Deyang shi Yaowei Liu Jin shi Institute of Geophysics China Earthquake AdministrationBeijing 10081China National Institute of Natural Hazards Ministry of Emergency Management of People's Republic of ChinaBeijing 10085China College of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China

Carbonaceous materials in seismic fault zones may considerably influence seismic fault slip;however,the formation mechanism of carbonaceous materials remains *** this study,we proposed a novel hypothesis for the formation of carbonaceous materials in fault ***,we conducted a CO_(2) hydrogenation experiment in a high-temperature reactor at a co-seismic temperature,with fault gouge formed during the Wenchuan earthquake as the *** experimental results demonstrate that carbonaceous materials in fault zones are formed on the fault gouge during the chemical reaction process,suggesting that the carbonaceous materials are possibly generated from the catalytic hydrogenation of CO_(2),followed by thermal cracking of its *** results of this study provide a theoretical basis for understanding fault behavior and earthquake physics.

关键词： carbon dioxide hydrogenation carbonaceous mineral formation co-seismic temperature fault weakening fault gouge

GNSS gyroscopes:determination of angular velocity and acceleration with very high-rate GNSS

在线全文

学校读者我要写书评

暂无评论

Satellite Navigation 2024年第1期5卷 74-90页

作者： Yun shi Peiliang Xu Yuanming Shu Xiaolin Meng School of Geomatics Xi’an University of Science and TechnologyXi’an710054People’s Republic of China Disaster Prevention Research Institute Kyoto UniversityUjiKyoto611-0011Japan College of Marine Geosciences Ocean University of ChinaQingdaoPeople’s Republic of China School of Instrument Science and Engineering Southeast UniversityNanjing210096People’s Republic of China

Although global navigation satellite systems(GNSS)have been routinely applied to determine attitudes,there exists no literature on determining angular velocity and/or angular acceleration from *** by the invention of computerized accelerometers of the correspondence author and following the success of accurately recovering translational velocity and acceleration waveforms from very high-rate GNSS precise positioning by Xu and his collaborators in 2021,we propose the concept of GNSS gyroscopes and reconstruct angular velocity and acceleration from very high-rate GNSS attitudes by applying regularization under the criterion of minimum mean squared *** major results from the experiments can be summarized in the following:(i)angular velocity and acceleration waveforms computed by applying the difference methods to high-rate GNSS attitudes are too noisy and can be physically not meaningful and numerically *** same can be said about inertial measurement unit(IMU)attitudes,if IMU gyros are not of very high accuracy;(ii)regularization is successfully applied to reconstruct the high-rate angular velocity and acceleration waveforms from 50 Hz GNSS attitudes and significantly outperforms the difference methods,validating the proposed concept of GNSS *** comparing the angular velocity and acceleration results by using the difference methods and regularization,we find that the peak values of angular velocity and acceleration by regularization are much smaller by a maximum factor of 1.57 in the angular velocity to a maximum factor of 8662.53 times in the angular acceleration in the case of high-rate GNSS,and by a maximum factor of 1.26 in the angular velocity to a maximum factor of 2819.85 times in the angular acceleration in the case of IMU,respectively;and(iii)the IMU attitudes apparently lead to better regularized angular velocity and acceleration waveforms than the high-rate GNSS attitudes,which can well be explained by the fact that the

关键词： Angular velocity Angular acceleration High-rate GNSS GNSS attitudes GNSS gyroscopes Regularization

Systematic study of the synthesis of heavy and superheavy nuclei in 48Ca-induced fusion-evaporation reactions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第7期35卷 157-172页

作者： shi-Hao Zhu Tian-Liang Zhao Xiao-Jun Bao Department of Physics Collaborative Innovation Center for Quantum EffectsKey Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationHunan Normal UniversityChangsha410081China School of Nuclear Science and Technology Lanzhou UniversityLanzhou730000China School of Physics Xi’an Jiaotong UniversityXi’an710049China

We systematically studied the evaporation residue cross sections of ^(48)Ca-induced reactions on lanthanide and actinide target nuclei under the Dinuclear System(DNS)model framework to check the reliability and applicability of the *** produce new proton-rich Fl and Lv isotopes through hot fusion reactions in the superheavy element region with Z≥104,we utilized the reactions ^(48)Ca+^(236,238,239) Pu and ^(48)Ca+^(242,243,244,250) ***,owing to the detection limit of available equipment(0.1 pb),only 283Fl and 287−289Lv,which have the maximum evaporation residue cross section values of 0.149,0.130,9.522,and 0.309 pb,respectively,can be ***,to produce neutron-deficient isotopes of actinides near the proton drip line with Z=93−100,we attempted to generate the new isotopes(224−227Pu,228−232,237Cm)using the reactions ^(48)Ca+180,182,183 W and ^(48)Ca+^(184,186,187,192) *** maximum evaporation residue cross section values are 0.07,0.06,0.26,and 0.30 nb for the former set of reactions,and 1.96 pb,5.73 pb,12.16 pb,19.39 pb,54.79 pb,and 6.45 nb for the latter,*** results are expected to provide new information for the future synthesis of unknown neutron-deficient isotopes.

关键词： Dinuclear system(DNS)model Evaporation residue cross section Neutron-deficient isotopes

Clinical features and prognostic factors of duodenal neuroendocrine tumours:A comparative study of ampullary and nonampullary regions

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2024年第3期16卷 907-918页

作者： Sa Fang Yu-Peng shi Lu Wang Shuang Han Yong-Quan shi Department of Gastroenterology Honghui HospitalXi’an Jiaotong UniversityXi'an 710054Shanxi ProvinceChina Department of Gastroenterology The Second Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710032Shaanxi ProvinceChina Department of Gastroenterology Xijing Hospital Affiliated to Air Force Medical UniversityXi'an 710032Shaanxi ProvinceChina

BACKGROUND Duodenal neuroendocrine tumours(DNETs)are rare ***,the incidence of DNETs has been increasing in recent years,especially as an incidental finding during endoscopic ***,there is no consensus regarding the ideal treatment of *** there are few studies on the clinical features and survival analysis of *** To analyze the clinical characteristics and prognostic factors of patients with duodenal neuroendocrine *** The clinical data of DNETs diagnosed in the First Affiliated Hospital of Air Force Military Medical University from June 2011 to July 2022 were ***-docrine tumours located in the ampulla area of the duodenum were divided into the ampullary region group;neuroendocrine tumours in any part of the duo-denum outside the ampullary area were divided into the nonampullary region *** a retrospective study,the clinical characteristics of the two groups and risk factors affecting the survival of DNET patients were *** Twenty-nine DNET patients were *** male to female ratio was 1:1.9,and females comprised the *** ampullary region group accounted for 24.1%(7/29),while the nonampullary region group accounted for 75.9%(22/29).When diagnosed,the clinical symptoms of the ampullary region group were mainly abdominal pain(85.7%),while those of the nonampullary region groups were mainly abdominal distension(59.1%).There were differences in the composition of staging of tumours between the two groups(Fisher's exact probability method,P=0.001),with nonampullary stage II tumours(68.2%)being the main stage(P<0.05).After the diagnosis of DNETs,the survival rate of the ampullary region group was 14.3%(1/7),which was lower than that of 72.7%(16/22)in the nonampullary region group(Fisher's exact probability method,P=0.011).The survival time of the ampullary region group was shorter than that of the nonampullary region group(P<0.000).The median survival time of the ampullary

关键词： Duodenum Neuroendocrine Tumour Ampullary Nonampullary Clinical features Prognostic

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 405-417页

作者： Yi Yu Guo-Ping Liu Yi Huang Peng shi IEEE Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and TechnologyShenzhen 518055China School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China School of Electrical and Mechanical Engineering the University of AdelaideSA 5005Australia Research and Innovation Centre Obuda University1034 BudapestHungary

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

关键词： DC microgrids distributed control high-order fully actuated system approach linear quadratic regulator microgrid modeling secondary control

Combustion mechanism of benzene in iron ore sintering process:experimental and simulation

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1期31卷 195-203页

作者： Zhi-gang Que Jin-ming shi Xian-bin Ai Institute of Energy Research Jiangxi Academy of ScienceNanchang330096JiangxiChina Jiangxi Carbon Neutralization Research Center Nanchang330096JiangxiChina

Benzene is a typical component of volatile organic compounds(VOCs)in the iron ore sintering flue *** combustion behavior of benzene directly affects the emission of VOCs in iron ore sintering *** effects of temperature,benzene,and oxygen concentrations on the conversion ratio of benzene were investigated by experiments and numerical *** experiments were carried out in a tube reactor at temperatures of 773-1098 K,benzene concentrations of 0.01-0.03 vol.%,and oxygen concentrations of 10-21 vol.%.The numerical simulation was performed with the plug flow model in the CHEMKIN program based on a kinetic model that consists of 132 chemical species and 772 elementary step-like *** experimental results reveal that increasing the temperature and benzene concentration could signifi-cantly promote benzene *** is attributed to the increase in the reaction rates of all steps in the pathway for forming CO_(2)and H_(2)*** addition,due to the large equivalent ratio of oxygen to benzene,the conversion ratio of benzene remained constant at different oxygen *** simulation results were in good agreement with the experimental results and indicated that six elementary reactions dominated the formations of CO_(2)and H_(2)*** oxidations of C_(6)H_(5)O,CO,and C_(5)H_(4)O intermediates to CO_(2)were the limiting steps in the reaction pathways.

关键词： Benzene Volatile organic compound Iron ore sinter Combustion Simulation Temperature Oxygen

A low-melting-point metal doping strategy for the synthesis of small-sized intermetallic Pt5Ce fuel cell catalysts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8112-8118页

作者： Zi-Jun Zou shi-Yi Yin Yao Tang Sheng-Liang Zhong Lei Wang shi-Long Xu Hai-Wei Liang College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China Department of Chemistry University of Science and Technology of ChinaHefei 230026China School of Materials and Chemical Engineering Anhui Jianzhu UniversityHefei 230601China

Carbon-supported platinum-lanthanum(Pt-Ln)intermetallic compound(IMC)nanoparticles with high activity and robust stability have been demonstrated as promising cathode catalysts for proton-exchange membrane fuel ***,the preparation of Pt-Ln IMC catalysts needs high-temperature annealing treatment that inevitably causes nanoparticle sintering,resulting in significant reduction of the electrochemical surface area and mass-based ***,we prepare small-sized M-doped Pt5Ce(M=Ga,Cd,and Sb)IMCs catalysts via a low-melting-point metal doping *** speculate that the doping of low-melting-point metals can facilitate the generation of vacancies in the crystal lattice through thermal activation and thus reduce the kinetic barriers for the formation of intermetallic Pt5Ce *** prepared Ga-doped Pt5Ce catalyst exhibits a higher electrochemical active surface area(81 m^(2)·gPt^(-1))and a larger mass activity(0.45 A·mgPt^(-1)at 0.9 V)over the undoped Pt5Ce and commercial Pt/C *** the membrane electrode assembly test,the Ga-doped Pt5Ce cathode delivers a power density of 0.98 W·cm^(-2)at 0.67 V,along with a voltage loss of only 27 mV at 0.8 A·cm^(-2)at the end of accelerated stability test.

关键词： P5Ce low-melting-point metal small-sized intermetallic compound catalysis fuel cells

A Survey on Graph Neural Network Acceleration: A Hardware Perspective

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 Electronics 2024年第3期33卷 601-622页

作者： shi CHEN Jingyu LIU Li SHEN School of Computer National University of Defense Technology Key Laboratory of Advanced Microprocessor Chips and Systems

Graph neural networks(GNNs) have emerged as powerful approaches to learn knowledge about graphs and *** rapid employment of GNNs poses requirements for processing *** to incompatibility of general platforms,dedicated hardware devices and platforms are developed to efficiently accelerate training and inference of *** conduct a survey on hardware acceleration for *** first include and introduce recent advances of the domain,and then provide a methodology of categorization to classify existing works into three ***,we discuss optimization techniques adopted at different *** finally we propose suggestions on future directions to facilitate further works.

关键词： Graph neural networks Deep learning acceleration Domain-specific architecture Hardware accelerator MODEL