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Dendritic spine degeneration:a primary mechanism in the aging process
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作者 Gonzalo Flores Leonardo Aguilar-Hernández +3 位作者 Fernado García-Dolores Humberto Nicolini Andrea Judith Vázquez-Hernández Hiram Tendilla-Beltrán 《Neural Regeneration Research》 SCIE CAS 2025年第6期1696-1698,共3页
Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a w... Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a wide range of factors, spanning from genetic to environmental factors, and even includes the gut microbiome(GM)(Mayer et al., 2022). All these processes coincide at some point in the inflammatory process, oxidative stress, and apoptosis, at different degrees in various organs and systems that constitute a living organism(Mayer et al., 2022;AguilarHernández et al., 2023). 展开更多
关键词 AGING process STRESS
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基于Arduino与Processing的心率检测计设计研究 被引量:1
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作者 臧红波 华拓 管志岳 《家电维修》 2024年第3期74-76,共3页
随着社会经济的高速发展,人们的物质生活也有了极大的提高,但同时也伴随着各种疾病的到来,身体健康已经成为人们普遍关注的焦点,因此,心率检测仪、血压计、血糖仪等各种家用医疗监测仪器已经逐渐融入日常生活。心脏病是人们难以预防的... 随着社会经济的高速发展,人们的物质生活也有了极大的提高,但同时也伴随着各种疾病的到来,身体健康已经成为人们普遍关注的焦点,因此,心率检测仪、血压计、血糖仪等各种家用医疗监测仪器已经逐渐融入日常生活。心脏病是人们难以预防的突发致命疾病之一,本文介绍的是一款基于Arduino【是基于易用硬件和软件的原型开源平台,包由可编程的电路板(简称微控制器),以及集成开发环境(称为Arduino IDE)的现成软件组成】Processing(开源编程语言,包括编辑器、编译器、展示器)的简易心率检测计系统,其功能实用、操作简单,可以测量心率,当超出正常心率范围时及时预警,是一款便携的实时心率测试仪。 展开更多
关键词 Arduino processing 心率检测计 设计研究
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The application of amplitude-preserved processing and migration for carbonate reservoir prediction in the Tarim Basin,China 被引量:6
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作者 Sam Zandong Sun Yang Haijun +4 位作者 Zhang Yuanyin Han Jianfa WangDan Sun Wenbo Jiang Shan 《Petroleum Science》 SCIE CAS CSCD 2011年第4期406-414,共9页
Conventional seismic exploration method based on post-stack data usually fails to identify the distribution of fractured and caved carbonate reservoirs in the Tarim Basin,so the rich pre-stack information should be ap... Conventional seismic exploration method based on post-stack data usually fails to identify the distribution of fractured and caved carbonate reservoirs in the Tarim Basin,so the rich pre-stack information should be applied to the prediction of carbonate reservoirs.Amplitude-preserved seismic data processing is the foundation.In this paper,according to the feature of desert seismic data (including weak reflection,fast attenuation of high frequency components,strong coherent noises,low S/N and resolution),a set of amplitude-preserved processing techniques is applied and a reasonable processing flow is formed to obtain the high quality data.After implementing a set of pre-stack amplitude-preserved processing,we test and define the kernel parameters of amplitude-preserved Kirchhoff PSTM (pre-stack time migration) and subsequent gathers processing,in order to obtain the amplitude-preserved gathers used to the isotropic pre-stack inversion for the identification of caved reservoirs.The AVO characteristics of obtained gathers fit well with the synthetic gathers from logging data,and it proves that the processing above is amplitudepreserved.The azimuthal processing techniques,including azimuth division and binning enlargement,are implemented for amplitude-preserved azimuthal gathers with the uniform fold.They can be used in the anisotropic inversion to detect effective fractures.The processing techniques and flows are applied to the field seismic data,and are proved available for providing the amplitude-preserved gathers for carbonate reservoir prediction in the Tarim Basin. 展开更多
关键词 Amplitude-preserved processing amplitude-preserved pre-stack time migration azimuth carbonate reservoir Tarim Basin
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The migration of total dissolved solids during natural freezing process in Ulansuhai Lake 被引量:13
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作者 Yan ZHANG ChangYou LI +1 位作者 XiaoHong SHI Chao LI 《Journal of Arid Land》 SCIE 2012年第1期85-94,共10页
High total dissolved solids (TDS) content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the o... High total dissolved solids (TDS) content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the object of study. Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness. TDS profiles were drawn to show the distribution of TDS and to describe TDS migration. The results showed that about 80% (that is 3.602x108 kg) of TDS migrated from ice to water during the whole growth period of ice. Within ice layer, TDS migration only occurred during initial ice-on period, and then perished. The TDS in ice decreased with increasing ice thickness, following a negative exponential-like trend. Within un- der-ice water, the TDS migrated from ice-water interface to the entire water column under the effect of concentra- tion gradient until the water TDS content was uniform. In winter, 6.044x 107 kg (16.78% of total TDS) TDS migrated from water to sedirnent, which indicated that winter is the best time for dredging sediment. The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River. The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate, which reveals that ice growth rate is one of the determinants of TDS migration. The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas. 展开更多
关键词 arid and semiarid areas Ulansuhai Lake total dissolved solids (TDS) migration natural freezing process transferflux ice growth rate
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Study on fault-controlled hydrocarbon migration and accumulation process and models in Zhu I Depression 被引量:2
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作者 Wenqi Zhu Keqiang Wu +2 位作者 Ling Ke Kai Chen Zhifeng Liu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第2期107-113,共7页
Through the analysis of the faults and their internal structure in Zhu I Depression,it is found that the internal structure of the late fault is obviously segmented vertically.It develops unitary structure(simple faul... Through the analysis of the faults and their internal structure in Zhu I Depression,it is found that the internal structure of the late fault is obviously segmented vertically.It develops unitary structure(simple fault plane)in shallow layers,binary structure(induced fracture zone in hanging wall and sliding fracture zone in footwall)in middle,layers and ternary structure(induced fracture zone in hanging wall and sliding fracture zone in middle,and induced fracture zone in footwall)in deep layers.Because the induced fracture zone is a high porosity and permeability zone,and the sliding fracture zone is a low porosity and ultra-low permeability zone,the late fault in middle layers has the character of"transporting while sealing".The late fault can transport hydrocarbon by its induced fracture zone in the side of the hanging wall and seal hydrocarbon by its sliding fracture zone in the side of the footwall.In deep layers,the late fault has the character of"dual-transportation",induced fracture zones in both sides of hanging wall and footwall can transport hydrocarbon.The early fault that only developed in the deep layers is presumed to be unitary structure,which plays a completely sealing role in the process of hydrocarbon migration and accumulation due to inactivity during the hydrocarbon filling period.Controlled by hydrocarbon source,early/late faults,sand bodies and traps,two reservoir-forming models of"inverted L"and"stereo-spiral"can be proposed in middle layers,while two reservoir-forming models of"cross fault"and"lateral fault sealing"are developed in the deep layers of Zhu I Depression. 展开更多
关键词 fault structure transport/sealing migration and accumulation process reservoir-forming model Zhu I Depression
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Mechanism of Salt Migration Driven by Tectonic Processes:Insights from Physical and Numerical Modeling 被引量:2
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作者 YIN Hongwei ZHENG Mianping +2 位作者 ZHANG Zhen WU Zhenyun WANG Xingyuan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期273-274,共2页
1 Introduction Physical and numerical models are constructed to investigate the evolution and mechanism of salt migration driven by tectonic processes.In recent years,we have designed and ran series of models to simul... 1 Introduction Physical and numerical models are constructed to investigate the evolution and mechanism of salt migration driven by tectonic processes.In recent years,we have designed and ran series of models to simulate salt 展开更多
关键词 In Mechanism of Salt migration Driven by Tectonic processes
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Application of Seismic Interferometric Migration for Shallow Seismic High Precision Data Processing: A Case Study in the Shenhu Area 被引量:3
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作者 WEI Jia LIU Huaishan +1 位作者 XING Lei DU Dong 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第1期46-52,共7页
The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed under... The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed understanding of common submarine geological hazards. Current marine seismic exploration methods are based on the most effective detection technologies. Therefore, current research focuses on improving the resolution and precision of shallow stratum structure detection methods. In this article, the feasibility of shallow seismic structure imaging is assessed by building a complex model, and differences between the seismic interferometry imaging method and the traditional imaging method are discussed. The imaging effect of the model is better for shallow layers than for deep layers because coherent noise produced by this method can result in an unsatisfactory imaging effect for deep layers. The seismic interference method has certain advantages for geological structural imaging of shallow submarine strata, which indicates continuous horizontal events, a high resolution, a clear fault, and an obvious structure boundary. The effects of the actual data applied to the Shenhu area can fully illustrate the advantages of the method. Thus, this method has the potential to provide new insights for shallow submarine strata imaging in the area. 展开更多
关键词 SEISMIC INTERFEROMETRIC migration SHALLOW STRATA Shenhu area migration IMAGING
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Interface Migration between Martensite and Austenite during Quenching and Partitioning (Q&P) Process 被引量:19
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作者 Ning ZHONG Xiaodong WANG +1 位作者 Yonghua RONG Li WANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2006年第6期751-754,共4页
An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning (Q&P) process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interf... An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning (Q&P) process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interface migration is excluded in constrained paraequilibrium (CPE) model. Based on "endpoint" predicted by CPE model the thermodynamic condition of interface migration is analyzed, that is, the difference in the chemical potential of iron in both ferrite (martenisite) and austenite produces the driving force of the iron atoms to migrate from one phase to the other phase. In addition, the interface migration can change the austenite fraction; as a result, the austenite fraction at partitioning temperature may be higher than that at quenching temperature through the interface migration, but this phenomenon cannot be explained by CPE model. 展开更多
关键词 Quenching and partitioning (Q&P) Constrained paraequilibrium (CPE) MARTENSITE AUSTENITE Interface migration
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Geomorphology Processes of Channel Planform Migration on Meandering Rivers 被引量:3
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作者 LIN Zhipeng SHAN Jingfu CHEN Le 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第S1期134-135,共2页
1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoratio... 1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoration of rivers through the 展开更多
关键词 Geomorphology processes of Channel Planform migration on Meandering Rivers
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Characteristics of Element Migration in the Process of Wall-Rock Alteration in the Shibangou Gold Deposit,Western Henan 被引量:2
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作者 WEI Junhao LI Jianwei YUAN Yanbin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1999年第2期201-207,共7页
Abstract The Shibangou gold deposit in western Henan is associated with irregular quartz veinlets occurring in altered shear zones dissecting a dioritic intrusion. The altered shear zones are characterized by silicifi... Abstract The Shibangou gold deposit in western Henan is associated with irregular quartz veinlets occurring in altered shear zones dissecting a dioritic intrusion. The altered shear zones are characterized by silicification, pyritization, sericilization, chloritization and K-feldspar alteration. Zoning of altered rocks adjacent to the Au-bearing quartz veins is obviously exhibited. Fine-grained sulphides and quartz veinlets of different ages and small-scale fissures are widely distributed in the central part of the altered zones. Major mineralization types in this gold deposit are Au-bearing quartz veinlets and altered rocks in the shear zones. Samples were collected from drilling cores according to the alteration zoning and mineralization type and all samples were analyzed for major and trace elements. Mass balance, volume change (fv=97.3–71.9%) and major element variation sequences are studied in terms of major elements. The changes of mobile components (SiO2, K2O, Fe2O3) and CaO) and immobile component (Al2O3) in the wall-rock alteration are discussed. The gold mineralization is associated with the enrichment of As, Ag, Hg and Pb and depletion of Cu and Zn. The study of compositional variation of altered rocks proves to be a very efficient method for defining the extent of wall-rock alteration, fluid activity and mineralization and enrichment. 展开更多
关键词 wall-rock alteration element migration mass balance Shibangou gold deposit
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Mother Tongue Influence on the Learning of a Foreign Language Positive and Negative Migration of Mother Tongue in the Learning Process of English 被引量:1
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作者 谢超 《海外英语》 2010年第8X期152-154,共3页
With economy increasing globalization, English as an international language of its important position can not be ignored. English teaching in China has been attached to great importance. Among the four basic skills of... With economy increasing globalization, English as an international language of its important position can not be ignored. English teaching in China has been attached to great importance. Among the four basic skills of listening, speaking, reading and writing, writing is considered a high-level cognitive behavior, it reflects the author's way of thinking and cognitive characteristics. Chinese students learning English, will be more or less influenced by the mother tongue without doubt, this would be contrary to the requirements of Standard English. Language migration theory in the field of applied linguistics is a controversial topic. Language migration, that is, the impact of mother tongue on second language acquisition process, is a central issue in applied linguistics, language acquisition and language teaching. The research of Language transfer is an important component of the study of second language acquisition. The correct understanding to the language of the migration will help us deepen their understanding of second language acquisition. This article will focus on the phenomenon of migrations in the different languages, especially between the Chinese and English 展开更多
关键词 NATIVE LANGUAGE acquisition LANGUAGE migration COMPARATIVE analysis
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Hydro-mechanical analysis of rainfall-induced fines migration process within unsaturated soils 被引量:2
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作者 LEI Xiao-qin YANG Zong-ji +3 位作者 HE Si-ming LIU En-long WONG Henry LI Xin-po 《Journal of Mountain Science》 SCIE CSCD 2017年第12期2603-2619,共17页
Seepage-induced fines migration under rainfall infiltration is a main cause leading to shallow failures in loose colluvial slopes. To describe the full process of fines migration within unsaturated soils during rainfa... Seepage-induced fines migration under rainfall infiltration is a main cause leading to shallow failures in loose colluvial slopes. To describe the full process of fines migration within unsaturated soils during rainfall infiltration and the associated hydromechanical behaviors, a seepage-erosion-deformation coupled formulation is proposed in this paper. The governing equations proposed are implemented into a finite element code and used to investigate the influences of skeleton deformation on the rainfall infiltration process through unsaturated soil columns.The numerical results were presented in detail for a better understanding of the rainfall-induced fines migration process within unsaturated soils. Further,the obtained results are integrated into an infinite slope model for slope stability analysis. The results show that, the skeleton deformation will affect the rainfall infiltration rate and hence the timing of slope failures; meanwhile their influences are more evident if the fines deposition process is taken into account.Moreover, the slope stability could be reduced gradually due to the soil strength loss along with loss of fine particles. Therefore, particular attentions should be paid to analyzing the stability of soil slopes susceptible to internal erosion. 展开更多
关键词 Rainfall infiltration Fines migration Internal erosion Seepage deformation Slope stability
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MIGRATION CHARACTERISTICS OF MICROELEMENTS IN PROCESS OF LANDSCAPE GEOCHEMISTRY IN MT.NAMJAGBARWA AREA 被引量:1
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作者 窦贻俭 彭补拙 +2 位作者 赵培道 刘育民 李春华 《Chinese Geographical Science》 SCIE CSCD 1992年第3期51-61,共11页
To provide scientific basis for appraising natural resources in Mt. Namjagbarwa area, the migration characteristics of geochemical microelements, such as Zn, V, Ti, Pb, Ni, Cu, Cr, Co, Be and Ba, in the landscape zone... To provide scientific basis for appraising natural resources in Mt. Namjagbarwa area, the migration characteristics of geochemical microelements, such as Zn, V, Ti, Pb, Ni, Cu, Cr, Co, Be and Ba, in the landscape zones of alpine scrub and meadow, the mountainous dark coniferous forest, the mountainous mixed broadleaf and coniferous forest, the mountainous quasi-subtropical semi-evergreen broadleaf forest, the mountainous subtropical evergreen broadleaf forest, and the valley quasi-tropical monsoon rainforest have been described in the paper. 展开更多
关键词 microelement migration LANDSCAPE ZONE Mt. Namjagbarwa area
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Optimization of the seismic processing phase-shift plus finite-difference migration operator based on a hybrid genetic and simulated annealing algorithm 被引量:2
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作者 Luo Renze Huang Yuanyi +2 位作者 Liang Xianghao Luo Jun Cao Ying 《Petroleum Science》 SCIE CAS CSCD 2013年第2期190-194,共5页
Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome... Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome this defect, a finite-difference method in the frequency-space domain is introduced in the migration process, because it can adapt to strong lateral velocity variation and the coefficient is optimized by a hybrid genetic and simulated annealing algorithm. The two measures improve the precision of the approximation dispersion equation. Thus, the imaging effect is improved for areas of high-dip structure and strong lateral velocity variation. The migration imaging of a 2-D SEG/EAGE salt dome model proves that a better imaging effect in these areas is achieved by optimized phase-shift migration operator plus a finite-difference method based on a hybrid genetic and simulated annealing algorithm. The method proposed in this paper is better than conventional methods in imaging of areas of high-dip angle and strong lateral velocity variation. 展开更多
关键词 migration operator phase-shift plus finite-difference hybrid algorithm genetic andsimulated annealing algorithm optimization coefficient
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Numerical Simulation of Bubble Migration in Liquid Titanium Alloy Melt During Vertical Centrifugal Casting Process 被引量:1
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作者 Qin Xu Xing Wang Shiping Wu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2019年第6期91-96,共6页
The bubble migration in liquid titanium alloy melt during vertical centrifugal casting process has been predicted. The effects of different parameters, such as the initial bubble location, the mold rotational speed an... The bubble migration in liquid titanium alloy melt during vertical centrifugal casting process has been predicted. The effects of different parameters, such as the initial bubble location, the mold rotational speed and the mold rotational direction on the bubble in the migration process are investigated. The results show that the bubble migration can be divided into the radial movement to the mould rotation axis and the circular movement to the mould wall opposite to rotational direction of the casting mould. The casting mould wall has an impeditive effect on the circular movement of the bubble during its migration process. And the bubble finally migrates like a straight line along the mould wall located at the opposite direction of the rotational casting mould whether it rotates clockwise or anti-clockwise. The bubbles at the position near the mould wall located at the opposite direction of the rotational casting mould are much easier to migrate in a straight line. The instantaneous speed of the gas bubble increases with the increment of the mould rotational speed. However the mould rotational speed is high or low, the moving speed of the gas bubble increases slightly at the primary stage, and then decreases gradually like a ladder. 展开更多
关键词 titanium alloy vertical centrifugal casting gas bubble migration numerical simulation
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Directional migration behavior of cerium during sintering process of mischmetal doped cemented carbide 被引量:4
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作者 张立 陈述 +2 位作者 熊湘君 余贤旺 王元杰 《Journal of Central South University of Technology》 EI 2008年第1期6-10,共5页
Three observation methods were used to investigate the existing form and the behavior of rare earth during the sintering process of high activity mischmetal (RE, with lanthanum and cerium) doped WC-8%Co-0.048%RE(ma... Three observation methods were used to investigate the existing form and the behavior of rare earth during the sintering process of high activity mischmetal (RE, with lanthanum and cerium) doped WC-8%Co-0.048%RE(mass fraction) alloy with low carbon-containing level by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS), considering the fact that the addition amount of rare earth in the alloy is very minute. The directional migration process and mechanism of cerium were discussed. First, the sinter skin (surface) is observed. oxide on the sinter skin, and lanthanum in these cerium observed, and lanthanum containing phase/micro-zone in It is shown that there exists a dispersedly distributed cerium containing enrichment positions is very minute. Secondly, the polished section is the alloy is identified. Finally, based on the fact that the fracture of cemented carbide is resulted from the heterogeneous phase or other defects within the microstructure, the fracture surface is observed and cerium containing phase/micro-zone in the fracture source approximately 260 μm from the surface is identified. These combined observations reveal adequately the fact that lanthanum and cerium get separated and cerium predominantly migrates towards the surface during the sintering process. 展开更多
关键词 cemented carbide rare earth surface segregation directional migration liquid phase sintering
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THE ASYMPTOTIC PROPERTIES OF SUPERCRITICAL BISEXUAL GALTON-WATSON BRANCHING PROCESSES WITH IMMIGRATION OF MATING UNITS 被引量:1
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作者 马世霞 邢永胜 《Acta Mathematica Scientia》 SCIE CSCD 2006年第4期603-609,共7页
In this article the supercritical bisexual Galton-Watson branching processes with the immigration of mating units is considered. A necessary condition for the almost sure convergence, and a sufficient condition for th... In this article the supercritical bisexual Galton-Watson branching processes with the immigration of mating units is considered. A necessary condition for the almost sure convergence, and a sufficient condition for the L^1 convergence are given for the process with the suitably normed condition. 展开更多
关键词 Bisexual Galton-Watson branching processes IMmigration almost sure convergence L^1-convergence
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THE ERGODICITY FOR BI-IMMIGRATION BIRTH AND DEATH PROCESSES IN RANDOM ENVIRONMENT 被引量:1
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作者 胡迪鹤 张书林 《Acta Mathematica Scientia》 SCIE CSCD 2008年第1期43-53,共11页
The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in ran... The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in random environment Q(θ) with birth rate λ 〈 death rate μ, the following results are proved, (1) there is an unique q-process in random environment, P^-(θ*(0);t) = (p^-(θ^*(0);t,i,j),i,j ≥ 0), which is ergodic, that is, lim t→∞(θ^*(0);t,i,j) = π^-(θ^*(0);j) ≥0 does not depend on i ≥ 0 and ∑j≥0π (θ*(0);j) = 1, (2) there is a bi-immigration birth and death process in random enjvironment (X^* = {X^*,t ≥ 0},ε^* = {εt,t ∈ (-∞, ∞)}) with random transition matrix P^-(θ^* (0);t) such that X^* is a strictly stationary process. 展开更多
关键词 Density matrix in random environment random transition matrix Markov process in random environment bi-immigration birth and death density matrix in random environment bi-immigration birth and death process in random environment
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Research progress on isotopic fractionation in the process of shale gas/coalbed methane migration 被引量:3
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作者 LI Wenbiao LU Shuangfang +6 位作者 LI Junqian WEI Yongbo ZHAO Shengxian ZHANG Pengfei WANG Ziyi LI Xiao WANG Jun 《Petroleum Exploration and Development》 CSCD 2022年第5期1069-1084,共16页
The research progress of isotopic fractionation in the process of shale gas/coalbed methane migration has been reviewed from three aspects: characteristics and influencing factors, mechanism and quantitative character... The research progress of isotopic fractionation in the process of shale gas/coalbed methane migration has been reviewed from three aspects: characteristics and influencing factors, mechanism and quantitative characterization model, and geological application. It is found that the isotopic fractionation during the complete production of shale gas/coalbed methane shows a four-stage characteristic of “stable-lighter-heavier-lighter again”, which is related to the complex gas migration modes in the pores of shale/coal. The gas migration mechanisms in shale/coal include seepage, diffusion, and adsorption/desorption. Among them, seepage driven by pressure difference does not induce isotopic fractionation, while diffusion and adsorption/desorption lead to significant isotope fractionation. The existing characterization models of isotopic fractionation include diffusion fractionation model, diffusion-adsorption/desorption coupled model, and multi-scale and multi-mechanism coupled model. Results of model calculations show that the isotopic fractionation during natural gas migration is mainly controlled by pore structure, adsorption capacity, and initial/boundary conditions of the reservoir rock. So far, the isotope fractionation model has been successfully used to evaluate critical parameters, such as gas-in-place content and ratio of adsorbed/free gas in shale/coal etc. Furthermore, it has shown promising application potential in production status identification and decline trend prediction of gas well. Future research should focus on:(1) the co-evolution of carbon and hydrogen isotopes of different components during natural gas migration,(2) the characterization of isotopic fractionation during the whole process of gas generation-expulsion-migration-accumulation-dispersion, and(3) quantitative characterization of isotopic fractionation during natural gas migration in complex pore-fracture systems and its application. 展开更多
关键词 shale gas coalbed methane diffusive fractionation adsorption/desorption fractionation isotope fractionation model natural gas migration
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Benefit evaluation of the Three-Gorges Reservoir migration by an assessment index model based on analytic hierarchy process 被引量:1
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作者 WANG Jun-hui GAN Lian-jun 《Journal of Chongqing University》 CAS 2007年第2期100-106,共7页
An assessment index model was established to evaulate the benefit of the Three-Gorges Reservoir migration through the analytical hierarchy process. Totally 43 indicators were selected to assess the impact of migration... An assessment index model was established to evaulate the benefit of the Three-Gorges Reservoir migration through the analytical hierarchy process. Totally 43 indicators were selected to assess the impact of migration on the economic, social and ecological environmental aspects of the migration communities, with the data of the indicators of the years 1992, 1998, 2002 which represented the period of premigration, the end of the first phase migration and the end of the second phase migration, respectively. The evaluation matrix is sufficiently consistent, with a consistency ratio CR equal to 0.086 3. The assessment turned out a benefit value for the economic subsystem in the year 2004 larger than triple the value in the year 1992, indicating a remarkable economic growth in the Reservoir area. The constantly increasing value for the social subsystem reflects the stable social situations. There is a slight decline in the assessment outcome of the ecological subsystem for the year 1998, which implies enviromental conservation was given insufficient importance during that period. On the whole, the implementation of the migration project is favorable to the Reservoir region, as confirmed by the stably increasing overall evaluation value from 42.22% in 1992 to 68.81% in 2002. However, there is still much room to improve from the status quo to the target criteria. 展开更多
关键词 Three-Gorges Reservoir migration benefit index system comprehensive assessment
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