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Shear strength degradation of gas hydrate-bearing sediment due to partial hydrate dissociation

Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2749-2763页

作者： Yuan zhou Jiazuo zhou Pan Chen Changfu Wei State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China China University of Geosciences Wuhan430074China

Extraction of methane hydrate from subseafloor reservoir may potentially trigger seabed slides and induce *** address the problems,it is crucial to properly characterize the phase equilibrium condition of pore hydrate and the shear strength of the *** one of the key constitutive components,the phase equilibrium condition enforces a constraint over pore gas pressure,temperature and unhydrated water *** a constraint,however,has been traditionally ignored in analyzing the mechanical behavior of hydrate-bearing *** this paper,a series of stepwise hydrate dissociation tests was performed,and the phase equilibrium condition of pore hydrate was determined,providing an effective way to evaluate the unhydrated water content during hydrate ***,a series of direct shear tests was also conducted to explore the shear strength characteristics of the *** is shown that the shear strength of the hydrate-bearing soil can be significantly influenced by pore gas pressure,unhydrated water content,hydrate saturation and several other *** particular,the measured shear strength depends upon the initial water content of the sample,pointing to a potential problem that the shear strength could be wrongly determined if not properly interpreted.A shear strength criterion,which enforces the equilibrium condition of pore hydrate,is developed for hydrate-bearing soil,establishing a link between the equilibrium condition and the shear *** proposed equation describes well the shear strength characteristics of hydrate-bearing soils,remarkably unifying the effects of pore pressure,temperature,water content and hydrate saturation.

关键词： Hydrate-bearing soil Phase equilibrium condition Shear strength Unhydrated water content Mechanical behavior

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An automatic Q-factor matching method for eliminating 77%of the ZRO of a MEMS vibratory gyroscope in rate mode

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Microsystems & Nanoengineering 2024年第3期10卷 35-48页

作者： Jingbo Ren Tong zhou Yi zhou Yixuan Li Yan Su School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210000China

Mismatching quality factors(Q-factors)is one of the main factors causing zero-rate output(ZRO)in degenerate(DE)Micro-Electro-Mechanical Systems(MEMS)vibratory *** eliminate the ZRO of the DE MEMS gyroscope,this study introduces a method for real-time identification and automatic matching of Q-factors in rate *** leveraging the vibration characteristics of the DE MEMS vibratory gyroscope in rate mode,dedicated online test methods are designed to determine the Q-factors for both the drive and sense modes,enabling online identification of the Q-factor ***,an automatic Q-factor matching system is designed utilizing the mechanical-thermal dissipation mechanism of the resistive *** effectiveness of this proposed method is validated through simulations and experiments conducted on a MEMS disk resonator gyroscope(DRG).The results show a measurement error within 4%for Q-factor identification,and automatic Q-factor matching effectively reduces the ZRO by 77%.Employing this automatic Q-factor matching method successfully reduces the ZRO that is caused by the mismatching of Q-factors in the MEMS DRG from 0.11°/s to 0.025°/s and improves the bias instability(BI)from 0.40°/s to 0.19°/s.

关键词： matching mode method

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Quantitative characterization of fusion state of virgin and aged asphalt using nano-ferrous ferric oxide tracer

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 467-480页

作者： Qiang Li Song Liu Huameng Wen zhou zhou College of Civil Engineering Nanjing Forestry UniversityNanjing 210037China School of Transportation Southeast UniversityNanjing 211189China

The exact evaluation of the fusion rate of virgin and aged asphalt is essential to optimize the performance of the recycled asphalt *** fusion rate index was developed by tracing the distribution of tracer asphalt,which contains nano-ferrous ferric oxide(nano-Fe_(3)O_(4))*** fusion simulation tests were performed on three types of asphalt to obtain different fusion states,and fatigue tests were performed to evaluate the influence of the fusion rate on the fatigue life of the recycled *** was found that the tracer asphalt containing 4%nano-Fe_(3)O_(4)shows the optimal trace effect,and the developed fusion rate index can quantitatively characterize the influence of different factors on the fusion state of the recycled *** fusion state is closely related to the fatigue performance of recycled asphalt,and the fusion rate index can fairly evaluate its fatigue *** relationship between the fusion rate and the fatigue life of recycled asphalt depends on the factors that cause the fusion rate *** the influence of the amount of rejuvenator,the fatigue life of recycled asphalt grows exponentially with increasing fusion rate due to enhancement of molecular motion as well as a supplement of lightweight *** the influence of heat preservation treatment,fatigue life increases linearly with increasing fusion *** proposed fusion rate index can be utilized to quantitatively characterize the fusion state of virgin and aged asphalt,thus providing a simple way to guide the practical application of recycled asphalt.

关键词： Recycled asphalt Rejuvenator Tracing technique Fusion rate Fatigue

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Construction Activity Analysis of Workers Based on Human Posture Estimation Information

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Engineering 2024年第2期33卷 225-236页

作者： Xuhong zhou Shuai Li Jiepeng Liu zhou Wu Yohchia Frank Chen School of Civil Engineering Chongqing UniversityChongqing 400044China School of Automation Chongqing UniversityChongqing 400044China Department of Civil Engineering The Pennsylvania State UniversityMiddletownPA 17057USA

Identifying workers’construction activities or behaviors can enable managers to better monitor labor efficiency and construction ***,current activity analysis methods for construction workers rely solely on manual observations and recordings,which consumes considerable time and has high labor *** have focused on monitoring on-site construction activities of ***,when multiple workers are working together,current research cannot accu rately and automatically identify the construction *** research proposes a deep learning framework for the automated analysis of the construction activities of multiple *** this framework,multiple deep neural network models are designed and used to complete worker key point extraction,worker tracking,and worker construction activity *** designed framework was tested at an actual construction site,and activity recognition for multiple workers was performed,indicating the feasibility of the framework for the automated monitoring of work efficiency.

关键词： Pose estimation Activity analysis Object tracking Construction workers Automatic systems

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谈影响英语听力的问题阻隔及消解

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延边教育学院学报 2008年第3期22卷 69-72页

作者：周玉敏诸暨浣江中学浙江诸暨311800

在新一轮基础教育课程改革中,英语基础学科的地位再一次被强化,英语听力培养也放在非常重要的位置。但在实践中我们发现,大多数学生经过三年初中的英语学习,听力水平却始终难以提高。对此,本文就初中英语听力教学中影响学生听力水平发... 详细信息

在新一轮基础教育课程改革中,英语基础学科的地位再一次被强化,英语听力培养也放在非常重要的位置。但在实践中我们发现,大多数学生经过三年初中的英语学习,听力水平却始终难以提高。对此,本文就初中英语听力教学中影响学生听力水平发展的主要问题阻隔进行剖析并提出化解策略,以期在英语新课改教学中对如何提高学生听力水平起到抛砖引玉的作用。

关键词：英语听力问题阻隔消解策略

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Energy-information trade-off induces continuous and discontinuous phase transitions in lateral predictive coding

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 79-85页

作者： Zhen-Ye Huang Ruyi zhou Miao Huang Hai-Jun zhou Key Laboratory for Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China Minjiang Collaborative Center for Theoretical Physics Minjiang UniversityFuzhou 350108China

Lateral predictive coding is a recurrent neural network that creates energy-efficient internal representations by exploiting statistical regularity in sensory ***,we analytically investigate the trade-off between information robustness and energy in a linear model of lateral predictive coding and numerically minimize a free energy *** observed several phase transitions in the synaptic weight matrix,particularly a continuous transition that breaks reciprocity and permutation symmetry and builds cyclic dominance and a discontinuous transition with the associated sudden emergence of tight balance between excitatory and inhibitory *** optimal network follows an ideal gas law over an extended temperature range and saturates the efficiency upper bound of energy *** results provide theoretical insights into the emergence and evolution of complex internal models in predictive processing systems.

关键词： predictive coding recurrent neural network phase transition internal model free energy

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General properties of the spectral form factor in open quantum systems

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Frontiers of physics 2024年第3期19卷 229-237页

作者： Yi-Neng zhou Tian-Gang zhou Pengfei Zhang Institute for Advanced Study Tsinghua UniversityBeijing 100084China Department of Physics Fudan UniversityShanghai 200438China

The spectral form factor(SFF)can probe the eigenvalue statistic at different energy scales as its time variable *** closed quantum chaotic systems,the SFF exhibits a universal dip-ramp-plateau behavior,which reflects the spectrum rigidity of the *** this work,we explore the general properties of SFF in open quantum *** find that in open systems the SFF first decays exponentially,followed by a linear increase at some intermediate time scale,and finally decreases to a saturated plateau *** derive general relations between(i)the early-time decay exponent and Lindblad operators;(ii)the long-time plateau value and the number of steady *** also explain the effective field theory perspective of general *** verify our theoretical predictions by numerically simulating the Sachdev−Ye−Kitaev(SYK)model,random matrix theory(RMT),and the Bose−Hubbard model.

关键词： spectral form factor open quantum system quantum chaos

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一二八事变与上海金融市场

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档案春秋 1999年第1期 39-43页

作者：周育民

1931年下半年至1932年春，南京国民政府面临着极为严峻的形势：长江流域发生空前的水灾，两广军阀公开反蒋，九一八事变日寇入侵东北，12月蒋介石下野，1932年1月，日军又在上海发动了一二八事变。与政治形势紧密相关的上海公债市场随... 详细信息

1931年下半年至1932年春，南京国民政府面临着极为严峻的形势：长江流域发生空前的水灾，两广军阀公开反蒋，九一八事变日寇入侵东北，12月蒋介石下野，1932年1月，日军又在上海发动了一二八事变。与政治形势紧密相关的上海公债市场随之波澜迭起，对上海金融市场的发展产生了深（共5页)

关键词：上海华商证券交易所全国银行年鉴上海商业储蓄银行上海金融界公债还本付息一二八事变一·二八淞沪抗战上海银行界内债国债

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Origin and tectonic setting of low-Si alkaline magma

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Science China Earth Sciences 2024年第5期67卷 1417-1435页

作者： Qiushi zhou Rui WANG State Key Laboratory of Geological Processes and Mineral Resources and Institute of Earth SciencesChina University of GeosciencesBeijing 100083China Frontiers Science Center for Deep-time Digital Earth China University of Geosciences(Beijing)Beijing 100083China

Despite of the relatively rare occurrence of alkaline igneous rocks on Earth, they are the most diverse group of igneous rocks due to variations in their mineral assemblages and geochemical compositions. Alkaline igneous rocks are generally characterized by Si undersaturation, and K-Na(and in some cases C) enrichment. Although there is no unified alkaline igneous rock classification scheme, diagrams such as total alkalis-SiO_(2) or K_(2)O-SiO_(2) can be used to classify alkaline igneous rocks. The origins of silica-saturated alkaline rocks(SiO_(2)>52 wt.%) are relatively complex because multiple episodes of magmatism are often involved, therefore most studies have focused on the origins of silica-undersaturated alkaline *** experimental petrological studies have been conducted in the past few decades. Initially, it was considered that enrichment of trace elements was only achieved by low-degree partial melting of mantle peridotite, but the experimental melts could not reproduce the geochemical composition of natural alkaline igneous rocks. Subsequent studies have focused on carbonate-bearing eclogites that represent the average component of subducted oceanic crust. Although experimental studies indicate that silica-undersaturated and alkali-oversaturated melts can be generated from eclogites, some studies have considered that natural silica-undersaturated alkaline igneous rocks are the result of multi-stage source enrichment by incompatible elements. Low-degree partial melts of the mantle can be emplaced in the lithospheric mantle, forming veins consisting of phlogopite, amphibole, and pyroxene. Melting experiments including these components show that the produced melts better reproduce the naturally occurring silica-undersaturated alkaline magmas. Silica-deficient alkaline igneous rocks occur in various tectonic settings. Those in intraplate and divergent settings(i.e., mainly continental rifts) normally involve contributions from recycled components su

关键词： Alkaline igneous rock Tectonic setting Petrogenesis Big data

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Revealing the Void Formation Mechanism during Superplastic Deformation of a Fine-Grained Ni-Co-Base Superalloy

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 915-920页

作者： Rashad AAl-Hammadi Rui Zhang Chuanyong Cui Zijian zhou Yizhou zhou Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The mechanism behind void formation during superplasticity remains a subject of *** study presented a novel insight into the void formation in a fine-grained Ni-Co-based superalloy during *** was observed that the dissolution ofγ′-particles resulted in the creation of vacancies due to differences in atomic size between the matrix and the *** vacancies acted as inclusions,leading to the formation of ***,excessive void formation correlated with higher particle dissolution was experimentally observed,highlighting a direct relationship between void formation and particle dissolution.

关键词： Superplasticity Void formation Ni-Co-based superalloy Microstructure

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