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Multifractal estimation of NMR T_(2) cut-off value in low-permeability rocks considering spectrum kurtosis: SMOTE-based oversampling integrated with machine learning

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Petroleum Science 2023年第6期20卷 3411-3427页

作者： Xiao-jun Chen Rui-Xue Zhang Xiao-Bo Zhao jun-wei yang Zhang-Jian Lan Cheng-Fei Luo Jian-Chao Cai MOE Key Laboratory of Tectonics and Petroleum Resources Wuhan430074HubeiChina Department of Chemical Engineering and Analytical Science The University of ManchesterManchesterM139PLUK Jianghan Oilfied SINOPECQianjiang430063HubeiChina Hainan Branch of CNOOC Ltd Haikou570311HainanChina CNOOC EnerTech-Drilling&Production Co.CNOOC Central Laboratory(Zhanjiang) Zhanjiang524057GuangdongChina National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China

The transverse relaxation time (T_(2)) cut-off value plays a crucial role in nuclear magnetic resonance for identifying movable and immovable boundaries, evaluating permeability, and determining fluid saturation in petrophysical characterization of petroleum reservoirs. This study focuses on the systematic analysis of T_(2) spectra and T_(2) cut-off values in low-permeability reservoir rocks. Analysis of 36 low-permeability cores revealed a wide distribution of T_(2) cut-off values, ranging from 7 to 50 ms. Additionally, the T_(2) spectra exhibited multimodal characteristics, predominantly displaying unimodal and bimodal morphologies, with a few trimodal morphologies, which are inherently influenced by different pore types. Fractal characteristics of pore structure in fully water-saturated cores were captured through the T_(2) spectra, which were calculated using generalized fractal and multifractal theories. To augment the limited dataset of 36 cores, the synthetic minority oversampling technique was employed. Models for evaluating the T_(2) cut-off value were separately developed based on the classified T_(2) spectra, considering the number of peaks, and utilizing generalized fractal dimensions at the weight weight weight >0. The primary objective of this work is to gain insights into the relationship between the kurtosis of the T_(2) spectrum and pore types, as well as to predict the T_(2) cut-off value of low-permeability rocks using machine learning and data augmentation techniques.

关键词： Nuclear magnetic resonance Low-permeability porous media T_(2)cut-off value Fractal and multifractal Data augmentation Machine learning

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Development of Ti–V–Mo Complex Microalloyed Hot-Rolled 900-MPa-Grade High-Strength Steel

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Acta Metallurgica Sinica(English Letters) 2015年第5期28卷 641-648页

作者： Ke Zhang Zhao-Dong Li Xin-jun Sun Qi-Long Yong jun-wei yang Yuan-Mei Li Pei-Lin Zhao Department of Materials Science and Engineering Kunming University of Science and Technology Central Iron and Steel Research Institute Department of Materials Science and Engineering Huazhong University of Science and Technology R&D Center Laiwu Iron and Steel Group Co Ltd

A new Ti-V-Mo complex microalloyed hot-rolled high-strength steel sheet was developed by controlling a thermo-mechanical controlled processing （TMCP） schedule, in particular with variants in coiling temperature. The effects of coiling temperature （CT） on various hardening mechanisms and mechanical properties of Ti-V-Mo complex mi- croalloyed high-strength low-alloy steels were investigated. The results revealed that the steels are mainly strengthened by a combined effect of ferrite grain refinement hardening and precipitation hardening. The variation in simulated coiling temperature causes a significant difference in strength, which is mainly attributed to different precipitation hardening increment contributions. When the CT is 600 ℃, the experimental steel has the best mechanical properties： ultimate tensile strength （UTS） 1000 MPa, yield strength （YS） 955 MPa and elongation （EL） 17%. Moreover, about 82 wt% of the total precipitates are nano-sized carbide particles with diameter of 1-10 nm, which is randomly dispersed in the ferrite matrix. The nano-sized carbide particles led to a strong precipitation hardening increment up to 310 MPa.

关键词： Hot-rolled high-strength steel Strengthening mechanism Nano-sized carbide Precipitationhardening Coiling temperature

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Insight into Neuroethical Considerations of the Newly Emerging Technologies and Techniques of the Global Brain Initiatives

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Neuroscience Bulletin 2023年第4期39卷 685-689页

作者： Christopher R.Wood Yongmei Xi wei-jun yang Hao Wang MOE Laboratory of Biosystem Homeostasis and Protection College of Life SciencesZhejiang UniversityHangzhou310058China Institute of Genetics Zhejiang Provincial Key Laboratory of Genetic and Developmental DisordersZhejiang University School of MedicineHangzhou310058China Department of Neurobiology and Department of Neurosurgery of Second Affiliated Hospital Key Laboratory for Biomedical Engineering of Education MinistryZhejiang University School of MedicineHangzhou310058China NHC and CAMS Key Laboratory of Medical Neurobiology Key Laboratory of Precise Treatment and Clinical Translational Research of Neurological DiseasesMOE Frontier Science Centre for Brain Research and Brain Machine IntegrationSchool of Brain Science and Brain MedicineZhejiang UniversityHangzhou310058China

Introduction At the rock face of neurobiology stand seven global brain initiatives.Through them,much of the global funding for neuroscience and neurotechnology(over 9 billion USD)is being channeled,and the rapid development of new techniques and technologies is the result.Some ethicists have questioned the sufficiency of the pre-existing ethical and legal frameworks to provide adequate oversight for such rapidly-emerging neurotechnologies and their often-unique applications and implications.

关键词： legal ethical funding

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Tailoring the Crystallization Behavior and Mechanical Property of Poly(glycolic acid) by Self-nucleation

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Chinese Journal of Polymer Science 2022年第4期40卷 365-372页

作者： Jia-Xuan Li De-Yu Niu Peng-Wu Xu Zhao-yang Sun wei-jun yang yang Ji Pi-Ming Ma The Key Laboratory of Synthetic and Biological Colloids Ministry of EducationJiangnan UniversityWuxi 214122China Inner Mongolia Pujing Polymer Material Technology Corporation Ltd. Baotou 014060China

Biocompostable poly(glycolic acid)(PGA)crystallizes slowly under fast cooling condition,leading to poor mechanical performance of the final products.In this work,a self-nucleation(SN)route was carried out to promote the crystallization of PGA by regulating only the thermal procedure without any extra nucleating agents.When self-nucleation temperature(Ts)decreased from 250℃ to 227℃,the nuclei density was increased,and the non-isothermal crystallization temperature(Tc)of PGA was increased from 156℃ to 197℃ and the half-life time(t0.5)of isothermal crystallization at 207℃ was decreased by 89%.Consequently,the tensile strength and the elongation at break of the PGA were increased by 12%and 189%,respectively.According to the change of Tc as a function of Ts,a three-stage temperature domain map(Domain I,II and III)was protracted and the viscoelastic behavior of the self-nucleation melt and the homogeneous melt was studied.The results indicated that interaction among PGA chains was remained in Domain IIb,which can act as pre-ordered structure to accelerate the overall crystallization rate.This work utilizes a simple and effective SN method to regulate the crystallization behavior and the mechanical properties of PGA,which may broaden the application range of resulting materials.

关键词： Poly(glycolic acid) Self-nucleation Crystallization kinetics Mechanical property

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Robust Poly(glycolic acid) Films with Crystal Orientation and Reinforcement of Chain Entanglement Network

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Chinese Journal of Polymer Science 2023年第7期41卷 1093-1103页

作者： De-Yu Niu Peng-Wu Xu Si-Jie Xu Jia-Xuan Li wei-jun yang Pi-Ming Ma The Key Laboratory of Synthetic and Biological Colloids Ministry of EducationJiangnan UniversityWuxi214122China

The inherent brittleness of biodegradable poly(glycolic acid) (PGA) restricts its utilization in the packaging field. Traditional toughening methods usually require additional components accompanied by a sacrifice of strength. In the present work, PGA films with simultaneously enhanced strength and ductility are achieved via “casting-stretching-annealing” technology. The reinforced chain entanglement network of PGA induced by the intense extensional stress and the highly oriented crystals grown and refined during the stretching and annealing process endowed the improved ductility and strength of the PGA films, respectively. The relationships among the stretching process, microstructure and mechanical properties of the PGA films have been systematically investigated. As a result, the PGA film (SA-2) with low stretch ratios exhibits excellent ductility with an increase in elongation at break from 22% to 220% and tensile strength from 56 MPa to 130 MPa. Meanwhile, the PGA film (SA-4) with large stretch ratios features much higher tensile strength (335 MPa) while maintaining good ductility (elongation at break of 66%). In addition, highly oriented crystals result in obvious enhancement of heat resistance and dimensional stability of the PGA films. Therefore, this work provides an effective route to fabricate PGA films with both high strength and ductility which may promote the application of PGA materials.

关键词： Poly(glycolic acid) Uniaxial stretching Ductility Strength

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Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

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National Science Review 2024年第3期11卷 159-171页

作者： Rui Wen Shao jun wei Wu Zheng Xing Wang Hui Xu Han Qing yang Qiang Cheng Tie jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University Peng Cheng Laboratory Pazhou Laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

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Improvement on the Mechanical Performance and Resistance Towards Hydrolysis of Poly(glycolic acid)via Solid-state Drawing

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Chinese Journal of Polymer Science 2023年第1期41卷 14-23页

作者： Jia-Xuan Li De-Yu Niu Bo Liu Peng-Wu Xu wei-jun yang Pieter Jan Lemstra Pi-Ming Ma The Key Laboratory of Synthetic and Biological Colloids Ministry of EducationJiangnan UniversityWuxi214122China PlemPolco B.V. Roek 245508 KEVeldhoventhe Netherlands

Poly(glycolic acid)is a biocompatible as well as biocomposable polymer with superior mechanical and barrier properties and,consequently,has found important applications in both medical and packaging fields.However,the high hydrolysis rate in a high humidity environment restricts its application.In this work,a solid-state drawing process after melt extrusion is applied in order to produce fibrous PGA with enhanced mechanical properties and a much better resistance towards hydrolysis.The crystal structure of PGA gradually transformed from spherulites into oriented fibrous crystals in the stretching direction upon solid-state drawing.Meanwhile,both the length of microfibril and the size of lamellae increased initially with the drawing ratio(DR),while the chain-folded lamellae transformed into extended-chain fibrils at high(er)DR.The oriented structures lead to an overall improvement of the mechanical properties of PGA,e.g.,the tensile strength increased from 62.0±1.4 MPa to 910±54 MPa and the elongation at break increased from around 7%to 50%.Meanwhile,the heat capacity of totally mobile amorphous PGA(∆C_(p)^(0)=0.64 J·g^(−1)·℃^(−1))was reported for the first time,which was used to analyze the content of mobile amorphous fraction(XMAF)and rigid amorphous fraction(XRAF).Both the oriented chain-folded lamellae crystals and the tightly arranged RAF are beneficial to prevent water molecules from penetrating the matrix,thus improving the resistance towards hydrolysis.As a consequence,the fibrous PGA with a DR of 5 showed a tensile strength retention rate of 17.3%higher in comparison with the undrawn sample after 7-days accelerated hydrolysis.Therefore,this work provides a feasible method to improve the mechanical and resistance towards hydrolysis performance of PGA,which may broaden its application and prolong the shelf-life of PGA products.

关键词： Poly(glycolic acid) Solid-state drawing Fibrous crystal Mechanical property Hydrolysis resistance

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Synthesis of granulated Li_(1.33)Mn_(1.67)O_(4) via two antisolvent methods for lithium adsorption from gas-produced water

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Chinese Journal of Chemical Engineering 2024年第5期69卷 34-46页

作者： jun Qiu Lu-Ri Bao wei Guo Ying yang Shu-Ying Sun National Engineering Research Center for Integrated Utilization of Salt Lake Resource East China University of Science and TechnologyShanghai 200237China

Gas-produced water is an accompanying wastewater in the natural gas extraction process,and it is a potential liquid lithium resource that contains a considerable amount of lithium.This study investigated the feasibility of using manganese-based ion sieves to adsorb and extract lithium from gas-produced water.And we focused on the applicability of two different granulation methods,extrusion and droplet,in gas-produced water systems.Two types of H_(1.33)Mn_(1.67)O_(4) particles were prepared by the extrusion method(EHMO)and the droplet method(DHMO).The porosity of DHMO was much higher than that of EHMO,and the adsorption performance of DHMO increased with the decrease of binder concentration.DHMO prepared with a binder concentration of 0.14 g·ml^(-1)exhibited the best adsorption performance in gas-produced water,and the Li^(+)adsorption capacity could reach 25.14 mg·g^(-1).In gas-produced water,the adsorption equilibrium of DHMO only took 9 h,and the adsorption process conformed to the Langmuir model and pseudo-second-order kinetic model.The pore diffusion model(PDM)could well describe its adsorption process.Besides,DHMO showed a great selectivity to Li^(+),and the selectivity order of DHMO in gas-produced water was Li^(+)>Ba^(2+)>>Mg^(2+),Ca^(2+),Sr^(2+)>>Na^(+)>>K^(+).After 20 cycles,the Li^(+)adsorption capacity was still higher than 17.30 mg·g^(-1),and the rate of manganese dissolution was less than 1%.

关键词： Gas-produced water Granulation Li_(1.33)Mn_(1.67)O_(4)

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Mitochondrial dysfunction in type 2 diabetes:A neglected path to skeletal muscle atrophy

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World Journal of Orthopedics 2024年第2期15卷 101-104页

作者： Jian-jun Wu Hui-Min Xian Da-wei yang Fan yang Department of Cardiology The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150001Heilongjiang ProvinceChina Department of Orthopedic Surgery The Fourth Affiliated Hospital of Harbin Medical UniversityHarbin 150001Heilongjiang ProvinceChina State Key Laboratory of Component-based Chinese Medicine Tianjin University of Traditional Chinese MedicineTianjin 30000China

Over the course of several decades,robust research has firmly established the significance of mitochondrial pathology as a central contributor to the onset of skeletal muscle atrophy in individuals with diabetes.However,the specific intricacies governing this process remain elusive.Extensive evidence highlights that individuals with diabetes regularly confront the severe consequences of skeletal muscle degradation.Deciphering the sophisticated mechanisms at the core of this pathology requires a thorough and meticulous exploration into the nuanced factors intricately associated with mitochondrial dysfunction.

关键词： Mfn-2 Oxidative stress Mitochondria metabolism Skeletal muscle atrophy Diabetes

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Metal-Free Synthesis of 2-Aminobenzothiazoles via I2-Catalyzed Tandem Cyclization Reaction of Amines and Carbon Disulfide

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Chinese Journal of Chemistry 2024年第8期42卷 846-852页

作者： Ting Chen wei Feng Ruitong yang Shanping Chen Guo-jun Deng Key Laboratory for Green Organic Synthesis and Application of Hunan Province Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of EducationCollege of ChemistryXiangtan UniversityXiangtanHunan411105 China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHunan453007 China

Comprehensive Summary,A convenient approach for the construction of 2-aminobenzothiazoles via I2-catalyzed tandem cyclization reaction of amines and carbon disulfide has been developed.The present approach starts from simple and readily available starting materials,affording a series of 2-aminobenzothiazoles in up to 89%yields under metal-free conditions.In this work,C—H/N—H functionalization was achieved and multiple C-hetero bonds were successfully constructed in one pot.

关键词： Sulfur heterocycles C-H functionalization Cyclization Tandem reaction Transition-metal-free Amines lodine N-Heterocycles

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