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Petrophysical insights into pore structure in complex carbonate reservoirs using NMR data

PETROLEUM RESEARCH 2024年第3期9卷 439-450页

作者： Mondal, Ilius Singh, Kumar Hemant Indian Inst Technol Dept Earth Sci Mumbai India

The study delves into pore structure attributes within the complex Eocene carbonate of an Indian offshore field, encompassing pore throat, radius and their characteristics. Nuclear Magnetic Resonance (NMR) experimental data reveals crucial insights into pore structures and fluid states. This study compares the NMR T-2 distribution curve with capillary pressure data from the Mercury Injection Capillary Pressure (MICP) technique, deriving linear and nonlinear conversion coefficients to transform NMR T-2 spectra into equivalent pore radius distribution. Pore radius-dependent porosity partitioning, linked to permeability and the distribution of irreducible water, is conducted utilizing NMR-derived data. Following the T-2 cut-off analysis, a two-segment fractal analysis of NMR T-2 distribution is also carried out. This analysis unveils associations between fractal dimensions and various petrophysical parameters, including permeability, porosity, T2LM, irreducible water saturation and R-50. The NMR-derived pore radius distribution is mostly unimodal, occasionally slightly bimodal. Six different pore size classes (less than 0.05 mu m to more than 5 mu m) are analysed in relation to permeability, porosity and irreducible water. Small pores (<1 mu m) contribute more to irreducible water with low porosity and permeability. The fractal dimension of large pores correlates strongly with porosity, permeability, T2LM, irreducible water and R-50 suggesting significant impact on reservoir seepage capacity. In addition to porosity partitioning, the current study demonstrates effectiveness in modelling modified permeability and correlating it with in situ permeability when applied to field NMR log data from the study area. While numerous studies focus on sandstone, our study marks the pioneering attempt at a comprehensive analysis on complex carbonate reservoirs. (c) 2024 The Authors. Publishing services provided by Elsevier B.V. on behalf of KeAi Communication Co. Ltd. This is an ope

关键词： Pore structure NMR T-2 distribution Irreducible water Fractal analysis Permeability SANDSTONE MODEL

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Equivariant Tautological Integrals on Flag Varieties

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 463-486页

作者： Xiaobo ZHUANG Department of Mathematical sciences Zhejiang Sci-Tech UniversityHangzhou 310018China

The author apples the Atiyah-Bott-Berline-Vergne formula to the equivariant tautological integrals over flag varieties of types A,B,C,D,and recovers the formulas expressing the integrals as iterated residues at infini... 详细信息

关键词： Localization Flag variety Residue

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Construction and properties of venlafaxine hydrochloride sustained release system based on hollow mesoporous silica microspheres

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Particuology 2024年第3期86卷 205-210页

作者： Chenjing Liang Lingling Shi Zhengguo Chen Lan Zhou Zhaoxia Zhang Guoqing Zhang School of Materials science and Engineering Zhejiang Sci-tech UniversityHangzhouChina College of Textile science and Engineering Zhejiang Sci-tech UniversityHangzhouChina Zhejiang Provincial Innovation Center of Advanced Textile Technology ShaoxingChina

The aim of this work is to develop a venlafaxine hydrochloride sustained release system based on hollow mesoporous silica microspheres(HMSMs).HMSMs were innovatively prepared with tetraethyl silicate(TEOS)as the precursor and volatile n-heptane as a soft *** obtained HMSMs show a well-defined hollow structure with an average size of 967 nm and pore volume of 0.85 cm^(3)/g,implying it is a potential drug ***,venlafaxine hydrochloride(VF)was absorbed in the HMSMs with a content of 37.67% or *** sustained release effect is further measured by the dissolution in-strument at 37℃ and 50 rpm in ultrapure *** results showed that the HMSMs/VF system shows good sustained release properties compared with sustained release tablets with hydroxypropyl meth-ylcellulose as the main *** HMSMs sustained release system appears to be a promising candidate for a sustained drug release.

关键词： Hollowmesoporous silica microspheres(HMSMs) Venlafaxine hydrochloride Drug loading Sustained release

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In-beam gamma rays of CSNS Back-n characterized by black resonance filter

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NUCLEAR sciENCE AND TECHNIQUES 2024年第10期35卷 1-12页

作者： Wang, Jin-Cheng Ren, Jie Jiang, Wei Ruan, Xi-Chao Liu, Ying-Yi Yang, Hao-Lan Xu, Kuo-Zhi Pan, Xin-Yi Sun, Qi Bao, Jie Huang, Han-Xiong Bai, Hao-Fan Bai, Jiang-Bo Cao, Ping Chen, Qi-Ping Chen, Yong-Hao Duan, Wen-Hao Fan, An-Chuan Fan, Rui-Rui Feng, Chang-Qing Gu, Min-Hao Han, Chang-Cai Han, Zi-Jie He, Guo-Zhu He, Yong-Cheng Hong, Yang Hu, Yi-Wei Jiang, Zhi-Jie Kang, Ling Lan, Chang-Lin Li, Bo Li, Feng Li, Qiang Li, Xiao Li, Yang Liu, Jie Liu, Rong Liu, Shu-Bin Liu, Yi-Na Luan, Guang-Yuan Ning, Chang-Jun Qiu, Yi-Jia Ren, Wen-Kai Ren, Zhi-Zhou Song, Zhao-Hui Sun, Kang Tan, Zhi-Xin Tang, Jing-Yu Tang, Sheng-Da Wang, Li-Jiao Wang, Peng-Cheng Wang, Zhao-Hui Wen, Zhong-Wei Wu, Xiao-Guang Wu, Xuan Wu, Ze-Peng Xia, Cong Xie, Li-Kun Yi, Han Yu, Tao Yu, Yong-Ji Zhang, Guo-Hui Zhang, Hang-Chang Zhang, Qi-Wei Zhang, Xian-Peng Zhang, Yu-Liang Zhang, Zhi-Yong Zhao, Mao-Yuan Zhou, Zhi-Hao Zhu, Ke-Jun Zou, Chong China Inst Atom Energy Key Lab Nucl Data Beijing 102413 Peoples R China Chinese Acad sci Inst High Energy Phys Beijing 100049 Peoples R China Spallat Neutron Source sci Ctr Dongguan 523803 Peoples R China Chinese Acad sci Inst High Energy Phys State Key Lab Particle Detect & Elect Beijing 100049 Peoples R China Univ Chinese Acad sci Beijing 100049 Peoples R China Peking Univ Sch Phys State Key Lab Nucl Phys & Technol Beijing 100871 Peoples R China Fudan Univ Inst Modern Phys Shanghai 200433 Peoples R China Univ sci & Technol China State Key Lab Particle Detect & Elect Hefei 230026 Peoples R China Univ sci & Technol China Sch Nucl Sci & Technol Hefei 230026 Peoples R China Univ sci & Technol China Dept Modern Phys Hefei 230026 Peoples R China China Acad Engn Phys Inst Nucl Phys & Chem Mianyang 621900 Peoples R China Univ sci & Technol China USTC Archaeometry Lab Hefei 230026 Peoples R China Northwest Inst Nucl Technol Xian 710024 Peoples R China Lanzhou Univ Sch Nucl Sci & Technol Lanzhou 730000 Peoples R China Univ sci & Technol China Inst Adv Technol Hefei 230027 Peoples R China

The back-streaming white-neutron beamline (Back-n) of the China Spallation Neutron Source is an essential neutron- research platform built for the study of nuclear data, neutron physics, and neutron applications. Many types of cross-sectional neutron-reaction measurements have been performed at Back-n since early 2018. These measurements have shown that a significant number of gamma rays can be transmitted to the experimental stations of Back-n along with the neutron beam. These gamma rays, commonly referred to as in-beam gamma rays, can induce a non-negligible experimental background in neutron-reaction measurements. Studying the characteristics of in-beam gamma rays is important for understanding the experimental background. However, measuring in-beam gamma rays is challenging because most gamma-ray detectors are sensitive to neutrons; thus, discriminating between neutron-induced signals and those from in-beam gamma rays is difficult. In this study, we propose the use of the black resonance filter method and a CeBr3 scintillation detector to measure the characteristics of the in-beam gamma rays of Back-n. Four types of black resonance filters, Ta-181, Co-59, Ag-nat, and Cd-nat, were used in this measurement. The time-of-flight (TOF) technique was used to select the detector signals remaining in the absorption region of the TOF spectra, which were mainly induced by in-beam gamma rays. The energy distribution and flux of the in-beam gamma rays of Back-n were determined by analyzing the deposited energy spectra of the CeBr3 scintillation detector and using Monte Carlo simulations. Based on the results of this study, the background contributions from in-beam gamma rays in neutron-reaction measurements at Back-n can be reasonably evaluated, which is beneficial for enhancing both the experimental methodology and data analysis.

关键词： In-beam gamma rays Back-n Black filter resonance technique In-beam gamma rays Back-n CeBr3 scintillator Black filter resonance technique C6D6 DETECTOR SYSTEM LINE

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Advances in the research and application of neurokinin-1 receptor antagonists

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Journal of Zhejiang University-science B(Biomedicine & Biotechnology) 2024年第2期25卷 91-105页

作者： Xiangyu HONG Junjie MA Shanshan ZHENG Guangyu ZHAO Caiyun FU College of Life sciences and Medicine Zhejiang Sci-Tech UniversityHangzhou310018China

Recently,the substance P(SP)/neurokinin-1 receptor(NK-1R)system has been found to be involved in various human pathophysiological disorders including the symptoms of coronavirus disease 2019(COVID-19).Besides,studies in the oncological field have demonstrated an intricate correlation between the upregulation of NK-1R and the activation of SP/NK-1R system with the progression of multiple carcinoma types and poor clinical *** findings indicate that the modulation of SP/NK-1R system with NK-1R antagonists can be a potential broad-spectrum antitumor *** review updates the latest potential and applications of NK-1R antagonists in the treatment of human diseases and cancers,as well as the underlying ***,the strategies to improve the bioavailability and efficacy of NK-1R antagonist drugs are summarized,such as solid dispersion systems,nanonization,and *** a radiopharmaceutical therapeutic,the NK-1R antagonist aprepitant was originally developed as radioligand receptor to target NK-1R-overexpressing ***,combining NK-1R antagonists with other drugs can produce a synergistic effect,thereby enhancing the therapeutic effect,alleviating the symptoms,and improving patients’quality of life in several diseases and cancers.

关键词： Neurokinin-1 receptor(NK-1R)antagonist Pathophysiological disorder Tumor target Bioavailability Nanoencapsulation Synergistic therapy

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Braille Character Segmentation Algorithm Based on Gaussian Diffusion

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Computers, Materials & Continua 2024年第4期79卷 1481-1496页

作者： Zezheng Meng Zefeng Cai Jie Feng Hanjie Ma Haixiang Zhang Shaohua Li School of Computer science and Technology Zhejiang Sci-Tech UniversityHangzhou310018China

Optical braille recognition methods typically employ existing target detection models or segmentation modelsfor the direct detection and recognition of braille characters in original braille images. However, these methodsneed improvement in accuracy and generalizability, especially in densely dotted braille image environments. Thispaper presents a two-stage braille recognition framework. The first stage is a braille dot detection algorithmbased on Gaussian diffusion, targeting Gaussian heatmaps generated by the convex dots in braille images. Thisis applied to the detection of convex dots in double-sided braille, achieving high accuracy in determining thecentral coordinates of the braille convex dots. The second stage involves constructing a braille grid using traditionalpost-processing algorithms to recognize braille character information. Experimental results demonstrate that thisframework exhibits strong robustness and effectiveness in detecting braille dots and recognizing braille charactersin complex double-sided braille image datasets. The framework achieved an F1 score of 99.89% for Braille dotdetection and 99.78% for Braille character recognition. Compared to the highest accuracy in existing methods,these represent improvements of 0.08% and 0.02%, respectively.

关键词： Computer vision image recognition optical braille recognition

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Study on the thermo-hydraulic behaviors of the new-pattern fuel assembly in lead-based fast reactors based on OpenFOAM

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NUCLEAR sciENCE AND TECHNIQUES 2024年第10期35卷 1-14页

作者： Li, Yun-Xiang Yang, Run-Sheng Li, Yue Su, Xing-Kang Huang, Zi-Nan Meng, Lu Li, Song Xi, Bin Zhang, You-Peng Zhang, Lu Jiang, Wei Fudan Univ Inst Modern Phys Shanghai 200433 Peoples R China Lanzhou Univ Sch Nucl Sci & Technol Lanzhou 730000 Peoples R China Chinese Acad sci Inst Modern Phys Lanzhou 730000 Peoples R China

To improve the heat transfer efficiency of the coolant in lead-based fast reactors, this study optimized the configuration and rotational direction of the spacer wires in fuel assemblies to design a new-pattern fuel assembly. This study conducted detailed comparisons between traditional and new pattern fuel assembly rod bundles utilizing the open-source computational fluid dynamics platform, OpenFOAM. The results indicated that the new design may significantly reduce the pressure drop along the rod bundle, which is beneficial for lowering the pressure drop. Furthermore, this new design improved coolant mixing in the subchannels, which facilitated a more uniform temperature distribution and lower thermal gradients at the assembly outlet. These factors collectively reduced the thermal fatigue and creep in nearby internal components. Overall, the new-pattern fuel assembly proposed in this study may have better heat transfer performance, thereby enhancing the Integrated Thermal-Hydraulic factor by 48.2% compared to the traditional pattern.

关键词： Spacer wires Enhanced coolant mixing OpenFOAM CFD simulations 3-DIMENSIONAL FLOW

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Research on blade tip clearance cavitation and turbulent kinetic energy characteristics of axial flow pump based on the partially-averaged Navier-Stokes model

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Journal of Hydrodynamics 2024年第1期36卷 184-201页

作者： Xiao-qi Jia Shuai-kang Zhang Zu-chao Zhu Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou310018China

To reveal the cavitation forms of tip leakage vortex(TLV)of the axial flow pump and the flow mechanism of the flow field,this research adopts the partially-averaged Navier-Stokes(PANS)model to simulate the cavitation values of an axial flow pump,followed by experimental *** experimental result shows that compared with the shear stress transport(SST)k-ωmodel,the PANS model significantly reduces the eddy viscosity of the flow field to make the vortex structure clearer and allow the turbulence scale to be more robustly *** cavitation area within the axial flow pump mainly comprises of TLV cavitation,clearance cavitation and tip leakage flows combined effect of triangular cloud cavitation *** formation and development of cavitation are accompanied by the formation and evolution of vortex,and variations in vortex structure also generate and promote the development of *** addition,an in-depth analysis of the relationship between the turbulent kinetic energy(TKE)transport equation and cavitation patterns was also conducted,finding that the regions with relatively high TKE are mainly distributed around gas/liquid boundaries with serious cavitation and evident gas-liquid *** phenomenon is mainly attributed to the combined effect of the pressure action term,stress diffusion term and TKE production term.

关键词： Cavitation axial flow pump tip leakage vortex(TLV) partially-averaged Navier-Stokes(PANS)model turbulent kinetic energy(TKE)

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Big Disaster from Small Watershed: Insights into the Failure and Disaster-Causing Mechanism of a Debris Flow on 25 September 2021 in Tianquan, China

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INTERNATIONAL JOURNAL OF DISASTER RISK sciENCE 2024年第4期15卷 622-639页

作者： Hou, Runing Wu, Mingyang Li, Zhi Chen, Ningsheng Chen, Xiaohu Peng, Taixin Huang, Na Chinese Acad sci Key Lab Mt Hazards & Surface Proc Inst Mt Hazards & Environm Chengdu 610041 Peoples R China Univ Chinese Acad sci Beijing 100049 Peoples R China Yangtze Univ Sch Geosci Wuhan 430100 Peoples R China Acad Plateau sci & Sustainabil Xining 810016 Peoples R China

The occurrence of debris flow events in small-scale watersheds with dense vegetation in mountainous areas that result in significant loss of life and missing individuals challenges our understanding and expertise in investigating and preventing these disasters. This has raised concerns about the occurrence of large debris flow disasters from small watersheds. This study focused on a catastrophic debris flow that took place in Longtou Gully (0.45 km2) in Tianquan County, Ya'an City on 25 September 2021, which resulted in 14 deaths and missing individuals. Through comprehensive field investigations, high-precision remote sensing data analyses, and numerical simulations, we analyzed the triggering mechanisms and dynamic processes of this event. Our results indicate that the convergence hollow at the channel head exhibited higher hydraulic conditions during rainfall compared to gentle slopes and convex terrains, leading to the instability of colluvial soil due to the expansion of the saturated zone near the soil-bedrock interface. The entrainment of material eroded from the channel resulted in an approximately 4.7 times increase in volume, and the channel scarp with a height of about 200 m amplified the destructive power of the debris flow. We emphasize the need to take seriously the possibility of catastrophic debris flows in small-scale watersheds, with colluvial deposits in hollows at the channel head under vegetation cover that serve as precursor material sources, and the presence of channel scarps formed by changes in the incision rate of the main river, which is common in the small watershed on both sides. This study provides insights for risk assessment of debris flows in small-scale catchments with dense vegetation cover in mountainous areas, highlighting the importance of vigilance in addressing disasters in small-scale catchments, particularly in regions with increasing human-environment conflicts.

关键词： China Colluvial soil Low-frequency debris flows Risk reduction Topographic hollows HILLSLOPE EROSION SHALLOW LANDSLIDES MODEL ENTRAINMENT RATES SOIL RADIOCARBON TOPOGRAPHY DEPOSITION CATCHMENT

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Effect of End Shape on Flow and Heat Transfer Characteristics of Two Parallel Plates

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Journal of Thermal science 2024年第3期33卷 815-832页

作者： ZHANG Guang HONG Tianxiao WANG Dongrui XIN Jialin TAO Junyu LIN Zhe Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou310018China

Flow around a pair of flat plates is a basic hydrodynamics *** this paper,the flow and heat transfer characteristics of two parallel plates with different edge shapes are numerically *** different inclined angles,the influence of chamfered and rounded structures with different sizes at the end-edge on unsteady flow and heat transfer characteristics of two parallel plates are *** is found that the instability and unsteadiness of flow decrease with the increase of end-edge size,and the non-uniformity of wake velocity of both rounded and chamfered plates decreases *** non-uniformity of wake temperature increases firstly and then decreases at a small inclined angle,and the amplitude becomes the largest when S_(rou)(S_(cha))=3,while it basically keeps monotonically increasing at a large inclined ***,the global heat transfer performance of the flat plate is obviously affected by the end-edge modification,especially the chamfered *** the increase of chamfered size,the global Nusselt number basically shows the decreasing *** study provides a theoretical basis for the application of plate-shape structure in engineering fields.

关键词： two parallel plates end shape flow characteristic heat transfer numerical simulation

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