期刊文献+
共找到789篇文章
< 1 2 40 >
每页显示 20 50 100
Small World Effects in a Harmonious Unifying Hybrid Preferential Model Networks
1
作者 FANG Jin-Qing BI Qiao LI Yong LU Xin-Biao LIU Qiang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第2X期377-383,共7页
Small worm effects in the harmonious unifying hybrid preferential model (HUHPM) networks are studied both numerically and analytically. The idea and method of the HUHPM is applied to three typical examples of unweig... Small worm effects in the harmonious unifying hybrid preferential model (HUHPM) networks are studied both numerically and analytically. The idea and method of the HUHPM is applied to three typical examples of unweighted BA model, weighted BBV model, and the TDE rnodel, so-called HUHPM-BA, HUHPM-BBV and HUHPM- TDE networks. Comparing the HUHPM with current typical models above, it is found that the HUHPM networks has the smallest average path length and the biggest average clustering coefficient. The results demonstrate that the HUHPM is more suitable not only for the un-iveighted models but also for the weighted models. 展开更多
关键词 harmonious unifying hybrid preferential model small world effect network science
在线阅读 下载PDF
A Unifying Theory of Dark Energy, Dark Matter, and Baryonic Matter in the Positive-Negative Mass Universe Pair: Protogalaxy and Galaxy Evolutions
2
作者 Ding-Yu Chung 《Journal of Modern Physics》 2020年第7期1091-1122,共32页
This paper modifies the Farnes’ unifying theory of dark energy and dark matter which are negative-mass, created continuously from the negative-mass universe in the positive-negative mass universe pair. The first modi... This paper modifies the Farnes’ unifying theory of dark energy and dark matter which are negative-mass, created continuously from the negative-mass universe in the positive-negative mass universe pair. The first modification explains that observed dark energy is 68.6%, greater than 50% for the symmetrical positive-negative mass universe pair. This paper starts with the proposed positive-negative-mass 11D universe pair (without kinetic energy) which is transformed into the positive-negative mass 10D universe pair and the external dual gravities as in the Randall-Sundrum model, resulting in the four equal and separate universes consisting of the positive-mass 10D universe, the positive-mass massive external gravity, the negative-mass 10D universe and the negative-mass massive external gravity. The positive-mass 10D universe is transformed into 4D universe (home universe) with kinetic energy through the inflation and the Big Bang to create positive-mass dark matter which is five times of positive-mass baryonic matter. The other three universes without kinetic energy oscillate between 10D and 10D through 4D, resulting in the hidden universes when D > 4 and dark energy when D = 4, which is created continuously to our 4D home universe with the maximum dark energy = 3/4 = 75%. In the second modification to explain dark matter in the CMB, dark matter initially is not repulsive. The condensed baryonic gas at the critical surface density induces dark matter repulsive force to transform dark matter in the region into repulsive dark matter repulsing one another. The calculated percentages of dark energy, dark matter, and baryonic matter are 68.6 (as an input from the observation), 26 and 5.2, respectively, in agreement with observed 68.6, 26.5 and 4.9, respectively, and dark energy started in 4.33 billion years ago in agreement with the observed 4.71 <span style="white-space:nowrap;">&plusmn;</span> 0.98 billion years ago. In conclusion, the modified Farnes’ unifying theory reinterprets the Farnes’ equations, and is a unifying theory of dark energy, dark matter, and baryonic matter in the positive-negative mass universe pair. The unifying theory explains protogalaxy and galaxy evolutions in agreement with the observations. 展开更多
关键词 unifying Theory Farnes Dark Energy Dark Matter Baryonic Matter Negative Mass Positive-Negative Mass Universe Pair Protogalaxy Evolution Galaxy Evolution
在线阅读 下载PDF
Unifying Markets
3
作者 Zhu Weidong 《ChinAfrica》 2018年第5期10-11,共2页
An agreement signed in Kigali, capital of Rwanda, has caught the world's attention. On March 21, a total of 44 African countries agreed to establish the African Continental Free Trade Area (AfCFTA), aimed at creat ... An agreement signed in Kigali, capital of Rwanda, has caught the world's attention. On March 21, a total of 44 African countries agreed to establish the African Continental Free Trade Area (AfCFTA), aimed at creat ing a single continental market for goods and services with free movement of busi nesses and investments. The agreement, signed at the 10th Extraordinary Session of the Assembly of the African Union (AU), wlll be submitted for ratification by state parties in accordance with their domestic laws. 展开更多
关键词 EAC FTA unifying Markets EU
原文传递
ChinAfrica A Unifying Tool
4
《ChinAfrica》 2013年第9期11-11,共1页
Media has the ability to play an important role in providing readers with information with which to shape opinions, drive initiatives and open discussion on a wide variety of topics.ChinAfrica reader, Christopher S.A.... Media has the ability to play an important role in providing readers with information with which to shape opinions, drive initiatives and open discussion on a wide variety of topics.ChinAfrica reader, Christopher S.A.Gonolinje. 展开更多
关键词 ChinAfrica A unifying Tool
原文传递
Molecular Computational Anatomy:Unifying the Particle to Tissue Continuum via Measure Representations of the Brain
5
作者 Michael Miller Daniel Tward Alain Trouvé 《Biomedical Engineering Frontiers》 2022年第1期453-468,共16页
Objective.The objective of this research is to unify the molecular representations of spatial transcriptomics and cellular scale histology with the tissue scales of computational anatomy for brain mapping.Impact State... Objective.The objective of this research is to unify the molecular representations of spatial transcriptomics and cellular scale histology with the tissue scales of computational anatomy for brain mapping.Impact Statement.We present a unified representation theory for brain mapping based on geometric varifold measures of the microscale deterministic structure and function with the statistical ensembles of the spatially aggregated tissue scales.Introduction.Mapping across coordinate systems in computational anatomy allows us to understand structural and functional properties of the brain at the millimeter scale.New measurement technologies in digital pathology and spatial transcriptomics allow us to measure the brain molecule by molecule and cell by cell based on protein and transcriptomic functional identity.We currently have no mathematical representations for integrating consistently the tissue limits with the molecular particle descriptions.The formalism derived here demonstrates the methodology for transitioning consistently from the molecular scale of quantized particles—using mathematical structures as first introduced by Dirac as the class of generalized functions—to the tissue scales with methods originally introduced by Euler for fluids.Methods.We introduce two mathematical methods based on notions of generalized functions and statistical mechanics.We use geometric varifolds,a product measure on space and function,to represent functional states at the micro-scales—electrophysiology,molecular histology—integrated with a Boltzmann-like program to pass from deterministic particle descriptions to empirical probabilities on the functional states at the tissue scales.Results.Our space-function varifold representation provides a recipe for traversing from molecular to tissue scales in terms of a cascade of linear space scaling composed with nonlinear functional feature mapping.Following the cascade implies every scale is a geometric measure so that a universal family of measure norms can be introduced which quantifies the geodesic connection between brains in the orbit independent of the probing technology,whether it be RNA identities,Tau or amyloid histology,spike trains,or dense MR imagery.Conclusions.We demonstrate a unified brain mapping theory for molecular and tissue scales based on geometric measure representations.We call the consistent aggregation of tissue scales from particle and cellular scales,molecular computational anatomy. 展开更多
关键词 ANATOMY UNIFIED function
原文传递
Bridging the Domain Gap in Grounded Situation Recognition via Unifying Event Extraction across Modalities 被引量:1
6
作者 Qingwen Liu Zejun Li +5 位作者 Zhihao Fan Cunxiang Yin Yancheng He Jing Cai Jinhua Fu Zhongyu Wei 《Data Intelligence》 2025年第1期143-162,共20页
Event extraction extracts event frames from text, while grounded situation recognition detects events in images. As real-world applications frequently encounter a multitude of unforeseen events, certain researchers ha... Event extraction extracts event frames from text, while grounded situation recognition detects events in images. As real-world applications frequently encounter a multitude of unforeseen events, certain researchers have introduced cross-domain and in-domain event extraction, while grounded situation recognition primarily explores in-domain scenarios. Therefore, in this paper, we propose cross-domain grounded situation recognition and establish a new benchmark SWiG-XD. In this more challenging setting, we deepen the connection between the two tasks based on their underlying unity in two different modalities and explore how to transfer the generalization ability from text to images. Firstly, we utilize ChatGPT to automatically generate textual data, which can be divided into two categories. One category is directly matched with images, establishing a direct connection with the images. The other category encompasses all event types and possesses greater generalization. Then we employ a unified model framework to establish the association between textual concepts and local image features and achieve cross-domain generalization transfer across modalities through modality-shared prompts and self-attention mechanism. Furthermore, we incorporate textual data with higher generalization to further assist in improving generalization on images. The experimental results on the newly constructed benchmark demonstrate the effectiveness of our method. 展开更多
关键词 Event argument extraction Cross-domain generalization Unified cross-modal framework Modalityshared prompt Grounded situation recognition
原文传递
基于UPLC-Q-TOF MS技术结合UNIFI软件快速筛查中药中非法添加调节性功能化合物
7
作者 廖敏 王影超 +2 位作者 陈琪 姜莲 王海宁 《质谱学报》 北大核心 2025年第3期370-379,共10页
本研究采用超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF MS)技术结合UNIFI软件,建立了一种快速、准确检测中药中非法添加调节性功能化合物的方法。根据中药剂型的不同选择相应的样品制备方法,使用ACQUITY UPLC HSS T3色谱柱(2.1 mm&#... 本研究采用超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF MS)技术结合UNIFI软件,建立了一种快速、准确检测中药中非法添加调节性功能化合物的方法。根据中药剂型的不同选择相应的样品制备方法,使用ACQUITY UPLC HSS T3色谱柱(2.1 mm×100 mm,1.8μm),以乙腈-0.1%甲酸溶液为流动相进行梯度洗脱;在电喷雾离子源正离子模式下,使用MS^(E)模式采集数据。通过UNIFI软件建立靶向筛查数据库,并参考欧盟SANTE/11312/2021指南设定筛查条件,实现检测结果的自动化筛查。结果表明,本方法能够在12 min内快速筛查31种目标化合物,检出限为0.25~15.00 mg/kg(或mg/L)。在对20批次补肾壮阳类中药样品的检测中发现,7批次样品存在非法添加,其中4批次样品检出标准检测方法以外的化合物。该方法具有快速、准确、覆盖范围广且可灵活扩展的优点,可为中药中非法添加物的监管提供技术支持。 展开更多
关键词 超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF MS) UNIFI软件 中药 非法添加 调节性功能化合物 快速筛查
在线阅读 下载PDF
UPLC-Q-TOF/MS法分析金雀花总黄酮入血成分 被引量:2
8
作者 布比阿加尔·哈依拉提 秦亚迪 +2 位作者 程煜凤 沈静 姚军 《中成药》 北大核心 2025年第1期126-132,共7页
目的建立UPLC-Q-TOF/MS法分析金雀花总黄酮入血成分,探究其药效物质基础。方法分析采用ACQUITY UPLC BEH C 18色谱柱(100 mm×2.1 mm,1.7μm);流动相水(含0.1%甲酸)-乙腈,梯度洗脱;体积流量0.3 mL/min;柱温35℃;进样量5μL;电喷雾... 目的建立UPLC-Q-TOF/MS法分析金雀花总黄酮入血成分,探究其药效物质基础。方法分析采用ACQUITY UPLC BEH C 18色谱柱(100 mm×2.1 mm,1.7μm);流动相水(含0.1%甲酸)-乙腈,梯度洗脱;体积流量0.3 mL/min;柱温35℃;进样量5μL;电喷雾离子源(ESI);正负离子扫描。结合UNIFI平台,对提取物、空白血清和含药血清图谱进行差异分析,解析提取物经大鼠灌胃后血清原型成分和代谢产物。结果含药血清中初步鉴定出78种成分,包括8种原型成分和70种代谢产物。结论本实验可为进一步研究金雀花总黄酮药效物质和作用机制奠定基础。 展开更多
关键词 金雀花 总黄酮 入血成分 UPLC-Q-TOF/MS UNIFI
暂未订购
基于UPLC-Q-TOF-MS/MS结合UNIFI的珠子参皂苷类化学成分分析及多指标含量测定 被引量:1
9
作者 张苡嘉 杨婧潇 +4 位作者 胡新悦 黄嘉诚 王炜 刘乐平 严建业 《天然产物研究与开发》 北大核心 2025年第5期904-917,共14页
对珠子参中皂苷类成分进行定性鉴别分析,建立珠子参皂苷类多成分含量测定方法。采用超高效液相色谱-飞行时间质谱(UPLC-Q-TOF-MS/MS)技术对珠子参进行正、负离子模式扫描,使用UNIFI天然产物信息平台对珠子参所含的化学成分进行定性鉴别... 对珠子参中皂苷类成分进行定性鉴别分析,建立珠子参皂苷类多成分含量测定方法。采用超高效液相色谱-飞行时间质谱(UPLC-Q-TOF-MS/MS)技术对珠子参进行正、负离子模式扫描,使用UNIFI天然产物信息平台对珠子参所含的化学成分进行定性鉴别分析;以0.1%磷酸水-乙腈溶液为流动相进行梯度洗脱,柱温30℃,流速0.3 mL/min,进行珠子参皂苷类多成分含量测定。珠子参中共鉴定出39个化学成分,包括37个皂苷类化合物和2个皂苷母核,并总结了皂苷类化合物的裂解规律,建立了UPLC同时测定珠子参中人参皂苷Rb1、人参皂苷Ro、人参皂苷Rb3、竹节参皂苷IV、竹节参皂苷IVa、人参皂苷Rd、姜状三七皂苷R1和金盏花苷E的多指标含量测定方法,该方法中8个待测成分在检测质量浓度范围内线性关系良好,精密度、重复性、稳定性的相对标准偏差(relative standard deviation,RSD)均小于3.0%,样品中人参皂苷Rb1、人参皂苷Ro、人参皂苷Rb3、竹节参皂苷IV、竹节参皂苷IVa、人参皂苷Rd、姜状三七皂苷R1和金盏花苷E的平均加样回收率分别为102.4%、103.1%、97.97%、99.42%、102.7%、102.1%、95.23%、100.5%,RSD分别为1.0%、0.98%、0.81%、2.3%、0.81%、1.9%、0.96%、1.8%。该研究建立的方法可快速、准确地对珠子参中的皂苷类成分进行定性及定量分析。 展开更多
关键词 珠子参 UPLC-Q-TOF-MS/MS UNIFI 成分分析 含量测定
暂未订购
A harmonious unifying hybrid preferential model and its universal properties for complex dynamical networks 被引量:13
10
作者 FANG JinQing BI Qiao +2 位作者 LI Yong LU XinBiao LIU Qiang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2007年第3期379-396,共18页
To describe the real world which is a harmonious unification world with both de- terminism and randomness, we propose a harmonious unifying hybrid preferential model (HUHPM) of a certain class of complex dynamical net... To describe the real world which is a harmonious unification world with both de- terminism and randomness, we propose a harmonious unifying hybrid preferential model (HUHPM) of a certain class of complex dynamical networks. HUHPM is gov- erned only by the total hybrid ratio d/r according to the practical need. As some typical examples, the concepts and methods of the HUHPM are applied to the un-weighted BA model proposed by Barabási et al., the weighted BBV model pro- posed by Barat et al. and the weighted TDE model proposed by Wang et al. to get the so-called HUHPM-BA network, HUHPM-BBV network and HUHPM-TDE network. These HUHPM networks are investigated both analytically and numerically. It is found that the HUHPM reveals several universal properties, which more approach to the real-world networks for both un-weighted and weighted networks and have potential for applications. 展开更多
关键词 HARMONIOUS unifying HYBRID preferential MODEL total HYBRID ratio small world effect SCALE-FREE property un-weighted and WEIGHTED networks
原文传递
An Analysis about the Origin and Essence of Mass Based on Particle-Propagating Model and Wave Equations of Scalar Waves 被引量:1
11
作者 Jiang Jian-zhong Chen Xi-qi 《Journal of Environmental Science and Engineering(B)》 2025年第2期65-75,共11页
If the singularity of the cosmic Big Bang is taken as the origin of the reference coordinate system,the surrounding vacuum in the initial moments of it would exhibit radially-outward right-handed spiral motion at ligh... If the singularity of the cosmic Big Bang is taken as the origin of the reference coordinate system,the surrounding vacuum in the initial moments of it would exhibit radially-outward right-handed spiral motion at light speed.Based on this spatial motion hypothesis,we derive a unified field equation and a set of Maxwell’s equations for vacuum SWs(Scalar Waves)generating a huge spiral force field that drives the energy to spiral inwardly and distort,leading to the formation of mass.Furthermore,they also uncover that mass is fundamentally an ultimate expression of energy,manifesting as the result of spiral motion of space at light speed.And then,we indirectly validate the theory that coherent light waves’collision generate SWs and subsequently mass through the experiment verifying the Breit-Wheeler process.The establishment of our theory offers a new analytical tool for the exploration of mass origin,the cosmic Big Bang,unified field theories. 展开更多
关键词 QED(Quantum Electrodynamics) SW mass origin unified field theories
在线阅读 下载PDF
超高效液相色谱-四极杆-飞行时间高分辨质谱技术结合UNIFI高通量筛查面膜类化妆品中141种非法添加成分
12
作者 范晨丽 王海波 +1 位作者 蒋培 申二永 《分析科学学报》 北大核心 2025年第4期405-414,共10页
建立了一种基于超高效液相色谱-四极杆-飞行时间高分辨质谱技术,结合UNIFI软件的高通量筛查方法,用于检测面膜类化妆品中141种非法添加成分。样品经饱和氯化钠溶液溶解后,加入含0.5%甲酸的乙腈进行超声提取,采用Oasis HLB固相萃取小柱... 建立了一种基于超高效液相色谱-四极杆-飞行时间高分辨质谱技术,结合UNIFI软件的高通量筛查方法,用于检测面膜类化妆品中141种非法添加成分。样品经饱和氯化钠溶液溶解后,加入含0.5%甲酸的乙腈进行超声提取,采用Oasis HLB固相萃取小柱净化。使用BEH C18(100 mm×2.1 mm,1.7μm)色谱柱分离,并在电喷雾离子源(ESI)正负扫描模式下,采用MS^(E)模式采集化合物的质谱信息。通过化合物的母离子和二级碎片离子的精准质量数以及保留时间等参数,利用UNIFI软件构建筛查数据库。最终通过基质标曲外标法进行定量分析。141种非法添加成分响应值与浓度呈良好线性关系(R^(2)>0.99),检出限为0.15~1.35 mg/kg;定量限为0.45~4.05 mg/kg。空白基质样品(面贴式乳液剂和涂抹式膏霜剂)中加入3个水平点的平均回收率为63.0%~124.5%;日内、日间相对标准偏差(RSD)分别为1.2%~9.1%(n=6)和1.3%~13.9%(n=3)。采用该方法测定市售86批面膜类产品,检出1批氯倍他索丙酸脂和3批酮康唑,检出含量范围为0.3~561.3 mg/kg。该方法操作简便、高效准确,具有良好的专属性,可实现面膜类化妆品中141种非法添加成分的高通量筛查,为化妆品质量监管提供了可靠的技术支持。 展开更多
关键词 UPLC-Q-TOF-MS^(E) 面膜类化妆品 非法添加成分 UNIFI 高通量筛查
在线阅读 下载PDF
CHINA SCENE
13
《China Standardization》 2025年第5期8-11,共4页
Downloads of national standards exceed 10 million times in the first half of 2025 In response to social needs,State Administration for Market Regulation(SAMR)had steadily promoted the full-text disclosure and free dow... Downloads of national standards exceed 10 million times in the first half of 2025 In response to social needs,State Administration for Market Regulation(SAMR)had steadily promoted the full-text disclosure and free download of over 30,000 national standards that do not adopt international standards since the beginning of this year.In the first half of 2025,downloads exceeded 10 million times,providing strong support for the construction of a unified national market.Social groups accessing national standards for free increased significantly.In the first half of this year,the average monthly downloads of national standards surged tenfold from 190,000 times last year to 2.03 million times.Online reading reached nearly 15 million times,and page views hit 89 million times.The disclosure of national standards for free has effectively broken information barriers in standards,ensuring equal rights for business entities to read and download national standards. 展开更多
关键词 national standards construction unified national downloads market regulation information barriers unified national market
原文传递
Towards Efficient Vehicle Recognition:A Unified System for VMMR,ANPR,and Color Classification
14
作者 Saad Sadiq Kashif Sultan +2 位作者 Muhammad Sheraz Teong Chee Chuah Muhammad Usman Hashmi 《Computers, Materials & Continua》 2025年第11期3945-3963,共19页
Vehicle recognition plays a vital role in intelligent transportation systems,law enforcement,access control,and security operations—domains that are becoming increasingly dynamic and complex.Despite advancements,most... Vehicle recognition plays a vital role in intelligent transportation systems,law enforcement,access control,and security operations—domains that are becoming increasingly dynamic and complex.Despite advancements,most existing solutions remain siloed,addressing individual tasks such as vehicle make and model recognition(VMMR),automatic number plate recognition(ANPR),and color classification separately.This fragmented approach limits real-world efficiency,leading to slower processing,reduced accuracy,and increased operational costs,particularly in traffic monitoring and surveillance scenarios.To address these limitations,we present a unified framework that consolidates all three recognition tasks into a single,lightweight system.The framework utilizes MobileNetV2 for efficient VMMR,YOLO(You Only Look Once)for accurate license plate detection,and histogram-based clustering in the HSV color space for precise color identification.Rather than optimizing each module in isolation,our approach emphasizes tight integration,enabling improved performance and reliability.The system also features adaptive image calibration and robust algorithmic enhancements to ensure consistent results under varying environmental conditions.Experimental evaluations demonstrate that the proposedmodel achieves a combined accuracy of 93.3%,outperforming traditional methods and offering practical scalability for deployment in real-world transportation infrastructures. 展开更多
关键词 VMMR ANPR unified framework deep learning
在线阅读 下载PDF
Unified construction of prenylated and reverse-prenylated oxindoles from isoprene launched by Ni catalysis
15
作者 Ying-Ying Liu Ying Li +4 位作者 Xue-Ting Li Su-Yang Xu Ding-Wei Ji Xiang-Ping Hu Qing-An Chen 《Chinese Journal of Catalysis》 2025年第3期444-454,共11页
As important natural and pharmaceutical motifs,the catalytic construction of structurally diverse 3,3-disubstituted oxindoles often requires elaborate synthetic efforts on optimizations.Herein,we developed a simple an... As important natural and pharmaceutical motifs,the catalytic construction of structurally diverse 3,3-disubstituted oxindoles often requires elaborate synthetic efforts on optimizations.Herein,we developed a simple and divergent approach for constructing reverse-prenylated and prenylated oxindoles launched by Ni catalysis with bulk chemical isoprene.Using C3-unsubstituted oxindoles as starting materials,mono reverse-prenylation was demonstrated in high chemo-and regioselectivities facilitated by the combination of Ni(0)and monodentate phosphine ligand.Using the obtained reverse-prenylated oxindoles as versatile synthon,substitutions at the pseudobenzylic position with various electrophiles created vicinal quaternary centers in a concise way.With the help of additives(PPh3 and NaH),air could be directly used as green oxidant to construct prenylated and reverse-prenylatedα-hydroxy-oxindoles divergently from the same substrates.In situ esterification of prenylatedα-hydroxy-oxindoles allowed subsequent Friedel-Crafts substitutions with diverse nucleophiles to deliver prenyl substituted dimeric or spiro-oxindoles.This protocol provides a divergent synthetic approach for the construction of highly functionalized 3,3-disubstituted oxindoles,which have been otherwise difficult to access in a unified approach. 展开更多
关键词 Nickel catalysis Unified construction ISOPRENE (Reverse-)prenylation OXINDOLE
在线阅读 下载PDF
Ground reaction curves for strain-softening rock masses with ground reinforcement based on unified strength criterion
16
作者 CHEN Xuan-hao ZHANG Ding-li +1 位作者 SUN Zhen-yu CHEN Wen-bo 《Journal of Central South University》 2025年第9期3383-3404,共22页
Ground reinforcement is crucial for tunnel construction, especially in soft rock tunnels. Existing analytical models are inadequate for predicting the ground reaction curves (GRCs) for reinforced tunnels in strain-sof... Ground reinforcement is crucial for tunnel construction, especially in soft rock tunnels. Existing analytical models are inadequate for predicting the ground reaction curves (GRCs) for reinforced tunnels in strain-softening (SS) rock masses. This study proposes a novel analytical model to determine the GRCs of SS rock masses, incorporating ground reinforcement and intermediate principal stress (IPS). The SS constitutive model captures the progressive post- peak failure, while the elastic-brittle model simulates reinforced rock masses. Nine combined states are innovatively investigated to analyze plastic zone development in natural and reinforced regions. Each region is analyzed separately, and coupled through boundary conditions at interface. Comparison with three types of existing models indicates that these models overestimate reinforcement effects. The deformation prediction errors of single geological material models may exceed 75%. Furthermore, neglecting softening and residual zones in natural regions could lead to errors over 50%. Considering the IPS can effectively utilize the rock strength to reduce tunnel deformation by at least 30%, thereby saving on reinforcement and support costs. The computational results show a satisfactory agreement with the monitoring data from a model test and two tunnel projects. The proposed model may offer valuable insights into the design and construction of reinforced tunnel engineering. 展开更多
关键词 ground reinforcement STRAIN-SOFTENING unified strength criterion tunnel responses analytical model
在线阅读 下载PDF
Stress gradient analytic solution and reasonable support prestress of roadway surrounding rock based on unified strength criterion:A case study
17
作者 JING Suo-lin WEN Zhi-jie +2 位作者 ZUO Yu-jun LI Qiu-ju HAO Peng 《Journal of Central South University》 2025年第2期449-468,共20页
The stress gradient of surrounding rock and reasonable prestress of support are the keys to ensuring the stability of roadways.The elastic-plastic analytical solution for surrounding rock was derived based on unified ... The stress gradient of surrounding rock and reasonable prestress of support are the keys to ensuring the stability of roadways.The elastic-plastic analytical solution for surrounding rock was derived based on unified strength theory.A model for solving the stress gradient of the surrounding rock with the intermediate principal stress parameter b was established.The correctness and applicability of the solution for the stress gradient in the roadway surrounding rock was verified via multiple methods.Furthermore,the laws of stress,displacement,and the plastic zone of the surrounding rock with different b values and prestresses were revealed.As b increases,the stress gradient in the plastic zone increases,and the displacement and plastic zone radius decrease.As the prestress increases,the peak stress shifts toward the sidewalls,and the stress and stress gradient increments decrease.In addition,the displacement increment and plastic zone increment were proposed to characterize the support effect.The balance point of the plastic zone area appears before that of the displacement zone.The relationship between the stress gradient compensation coefficient and the prestress is obtained.This study provides a research method and idea for determining the reasonable prestress of support in roadways. 展开更多
关键词 PRESTRESS support compensation surrounding rock damage stress gradient analytic solution unified strength theory
在线阅读 下载PDF
Degradation of natural red mudstone subjected to long-term relative humidity cycles
18
作者 Kang Chen Rui Zhang +2 位作者 Shengyang Yuan Jie Ma Huan Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第9期5800-5815,共16页
This paper presents a multi-scale experimental investigation of the weathering degradation of red mudstone.Natural rocks were extracted from the surface ground to 120 m,inwhich three sets of samples were selected to c... This paper presents a multi-scale experimental investigation of the weathering degradation of red mudstone.Natural rocks were extracted from the surface ground to 120 m,inwhich three sets of samples were selected to consider the different initial rock fabrics.The long-term relative humidity(RH)cycles under two amplitudes were imposed on red mudstone to simulate the weathering process.After RH cycles,a series of uniaxial compression tests,Brazilian splitting tests and bender-extender element tests were carried out to examine the reduction in strength and stiffness.The objective of this study is to develop an extended stress-volume framework characterizing the degradation of natural red mudstone both at microscale and macroscale.Accompanied by the irreversible swelling of the rock specimen is the progressive degradation of strength,stiffness and Poisson's ratio.A unified exponential degradation model in terms of the irreversible volumetric strain was thus proposed to capture such a degradation pattern.The effect of the initial rock fabric was evident.The highest degradation rate and potential were identified in slightly weathered specimens.Significant slaking of aggregates and crack propagation were confirmed by scanning electron microscope(SEM)micrographs,which were considered as the main consequence of structure damage leading to degradation of mechanical properties.The structure damage during RH cycles denoted the hysteresis nature in the response to the cycling hydraulic reaction,in turn causing the increase in volumetric strain.Thus,the stress-volume relation rather than the suction relation was found in more reasonable agreement with the experimental results. 展开更多
关键词 Red mudstone Weathering degradation Relative humidity cycles Unified degradation model Microstructure tests
在线阅读 下载PDF
UAF-based integration of design and simulation model for system-of-systems
19
作者 FENG Yimin GE Ping +2 位作者 SHAO Yanli ZOU Qiang LIU Yusheng 《Journal of Systems Engineering and Electronics》 2025年第1期108-126,共19页
Model-based system-of-systems(SOS)engineering(MBSoSE)is becoming a promising solution for the design of SoS with increasing complexity.However,bridging the models from the design phase to the simulation phase poses si... Model-based system-of-systems(SOS)engineering(MBSoSE)is becoming a promising solution for the design of SoS with increasing complexity.However,bridging the models from the design phase to the simulation phase poses significant challenges and requires an integrated approach.In this study,a unified requirement modeling approach is proposed based on unified architecture framework(UAF).Theoretical models are proposed which compose formalized descriptions from both topdown and bottom-up perspectives.Based on the description,the UAF profile is proposed to represent the SoS mission and constituent systems(CS)goal.Moreover,the agent-based simulation information is also described based on the overview,design concepts,and details(ODD)protocol as the complement part of the SoS profile,which can be transformed into different simulation platforms based on the eXtensible markup language(XML)technology and model-to-text method.In this way,the design of the SoS is simulated automatically in the early design stage.Finally,the method is implemented and an example is given to illustrate the whole process. 展开更多
关键词 model-based systems engineering unified architecture framework(UAF) system-of-systems engineering model transformation SIMULATION
在线阅读 下载PDF
The benefits and challenges of well monitoring of Gulong shale oil
20
作者 Yin Jia Chen Han Yi Wang Mukul Sharma 《Earth Energy Science》 2025年第2期120-122,共3页
This study discusses the benefits and challenges of well monitoring for Gulong shale oil production.It examines the Unified Transient Analysis(UTA)method,which integrates rate and pressure data to monitor changes in f... This study discusses the benefits and challenges of well monitoring for Gulong shale oil production.It examines the Unified Transient Analysis(UTA)method,which integrates rate and pressure data to monitor changes in fracture surface area and production efficiency in real-time.The UTA method allows for early detection of production impairments and provides feedback to optimize drawdown pressure,enhancing production without damaging fracture conductivity.Analysis of production data from Well A in the Daqing Oilfield demonstrates the method's efficacy,particularly in managing choke size adjustments and identifying fracture conductivity degradation.Despite its benefits,challenges such as data quality,manual data analysis,and the need for automated choke management are highlighted.The study underscores the necessity of integrating intelligent monitoring technologies and automating workflows to optimize Gulong shale oil production. 展开更多
关键词 Shale oil Well monitoring Rate transient analysis Unified transient analysis Choke management
在线阅读 下载PDF
上一页 1 2 40 下一页 到第
使用帮助 返回顶部