检索结果-南通市图书馆

Magnetic Resonance Letters 2024年第1期4卷 28-39页

作者： Lu Zhang Lizhi xiao Wensheng wu Guangzhi Liao yan Zhang Sihui Luo Xinglong Lei National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China College of Geophysics China University of PetroleumBeijing102249China PetroChina Huabei Oilfield Company China National Petroleum CorporationRenqiu062552China

The measurement of nuclear magnetic resonance(NMR)porosity is affected by *** considering the impact of NMR logging tools,this phenomenon is mainly caused by variations in magnetization intensity of the measured system due to temperature fluctuations and difference between the temperature of the porous medium and calibration *** this study,the effect of temperature was explained based on the thermodynamic theory,and the rules of NMR porosity responses to temperature changes were identified through core physics *** addition,a method for correcting the influence of temperature on NMR porosity measurement was proposed,and the possible factors that may affect its application were also discussed.

关键词： NMR porosity Temperature Porous media Intensity of magnetization

Nutritional values,bioactive compounds and health benefits of purslane(Portulaca oleracea L.):a comprehensive review

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第5期13卷 2480-2501页

作者： yanxi Li Longgao xiao Huan yan Mingyi wu xiaojiang Hao Haiyang Liu State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China Yunnan Characteristic Plant Extraction Laboratory Kunming 650106China

Portulaca oleracea L.,commonly known as purslane,is a worldwide weed species belonging to the family Portulacaceae and has been known as“Global Panacea”.As one of the most widely consumed green vegetables and medicinal plants around the world,it has recently been re-evaluated as a potential“new crop”due to the properties that differentiate it as one of the best vegetable sources of omega-3 fatty acid(α-linolenic acid),as well as a variety of nutrients and ***,emerging research has found that purslane exhibits health-promoting properties like anti-inflammatory,anti-hyperglycemic,antioxidant,neuroprotective,and *** findings suggest that this species possesses a potential using as a dietary supplement beyond potherb and traditional *** review systematically summarizes the up-to-date research carried out on purslane,including the nutritional compositions,bioactive compounds,and health benefits it exerts as well as limitations,challenges,and future directions of ***,we hope that this review would provide purslane with a comprehensive reference and future scope as functional and health-promoting food for disease prevention and treatment.

关键词： Purslane Nutritional compositions Bioactive compounds Polysaccharides Functional foods

Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第1期21卷 69-87页

作者： Chaowu wu Yue xiao Shu Fang Gang wu National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G *** approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the ***,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system *** conduct both computer simulations and experimental tests to validate the efficacy of our proposed *** results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

Numerical Investigation on Characteristics of Supercritical CO_(2)Heat Transfer in Vertical Circular Tubes with Circumferentially Half-Side Heating

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第5期33卷 1744-1756页

作者： ZHANG yan ZHANG Xinyi yan Chenshuai wu Wenhua GAO Erman School of Energy and Power Engineering Northeast Electric Power UniversityJilin 132012China

The design of heat exchangers in the advanced supercritical power conversion system cannot be separated from the study of heat transfer ***-side heating mode is often encountered for solar receiver and supercritical ***,the characteristics of supercritical CO_(2)(sCO_(2))convection heat transfer in vertical tubes with circumferentially half-side heating was numerically investigated through the SST k-ωturbulent model which matches well with the experimental ***,heat transfer between sCO_(2)upflow and downflow was *** to film boiling heat transfer at subcritical pressure,numerical results were processed according to the supercritical pseudo-phase transition hypothesis,with liquid-like phase in the tube core region and vapor-like film in the region near the heated tube *** structure of two layers was demarcated by pseudo-critical temperature T_(pc).Therefore,sCO_(2)heat transfer was assessed according to double thermal resistances caused by vapor-like film near the wall and core liquid-like *** findings suggest that wall temperature for upflow is higher than that for downflow,which is attributed to larger thermal resistance in the fluid domain for upflow than that for *** difference guarantees the excellent heat transfer performance for downflow than *** is also further concluded that the formation of vapor-like film near the wall due to pseudo-phase transition plays a key role in dominating wall temperature and inducing heat transfer deterioration in half-side heating *** present contribution is significant to the design of supercritical heat exchanger under half-side heating mode.

关键词： supercritical CO_(2) pseudo-phase transition half-side heating thermal resistance flow direction

A deep learning interatomic potential suitable for simulating radiation damage in bulk tungsten

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第2期6卷 304-322页

作者： Chang-Jie Ding Ya-Wei Lei xiao-yang Wang xiao-Lin Li Xiang-yan Li yan-Ge Zhang Yi-Chun Xu Chang-Song Liu Xue-Bang wu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island University of Science and Technology of ChinaHefei 230026China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.

关键词： Machine learning Deep learning Interatomic potential Radiation damage Tungsten

Review of data security within energy blockchain:A comprehensive analysis of storage,management,and utilization

在线全文

学校读者我要写书评

暂无评论

High-Confidence Computing

High-Confidence Computing 2024年第3期4卷 82-102页

作者： Yunhua He Zhihao Zhou yan Pan Fahui Chong Bin wu Ke xiao Hong Li School of Information Science and Technology North China University of TechnologyBeijing 100144China China Industrial Control Systems Cyber Emergency Response Team Beijing 100040China Key Laboratory in Blockchain and Data Security by Ministry of Industry and Information Technology Beijing 100040China Institute of Information Engineering Chinese Academy of Sciences Beijing 100195China

Energy systems are currently undergoing a transformation towards new paradigms characterized by decarbonization,decentralization,democratization,and *** this evolving context,energy blockchain,aiming to enhance efficiency,transparency,and security,emerges as an integrated technological solution designed to address the diverse challenges in this *** security is essential for the reliable and efficient functioning of energy *** pressing need to address challenges related to secure data storage,effective data management,and efficient data utilization is increasingly *** paper offers a comprehensive survey of academic discourse on energy blockchain data security over the past five years,adopting an all-encompassing perspective that spans data storage,management,and *** work systematically evaluates and contrasts the strengths and weaknesses of various research ***,this paper proposes an integrated hierarchical on-chain and off-chain security energy blockchain architecture,specifically designed to meet the complex security requirements of multi-blockchain business ***,this paper identifies key directions for future research,particularly in advancing the integration of storage,management,and utilization of energy blockchain data security.

关键词： Energy blockchain Data security Storage Management Utilization

Optically levitated micro gyroscopes with an MHz rotational vaterite rotor

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第3期10卷 219-227页

作者： Kai Zeng Xiangming Xu Yulie wu Xuezhong wu Dingbang xiao College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China College of Information and Communication National University of Defense TechnologyWuhan 430000China Key Laboratory of Satellite Navigation Technology National University of Defense TechnologyChangsha 410073China

The field of levitated optomechanics has experienced significant advancements in manipulating the translational and rotational dynamics of optically levitated particles and exploring their sensing *** concept of using optically levitated particles as gyroscopes to measure angular motion has long been explored but has not yet been proven either theoretically or *** this study,we present the first rotor gyroscope based on optically levitated high-speed rotating *** gyroscope is composed of a micrometer-size ellipsoidal vaterite particle that is driven to rotate at MHz frequencies in a vacuum *** an external angular velocity is input,the optical axis deviates from its initial position,resulting in changes in the frequency and amplitude of the rotational *** analyzing these changes,the angular velocity of the input can be accurately detected,making it the smallest rotor gyroscope in the *** angular rate bias instability of the gyroscope is measured to be 0.08°/s and can be further improved to as low as 10^(−9)°/h theoretically by cooling the motion and increasing the angular moment of the levitated *** work opens a new application paradigm for levitated optomechanical systems and may pave the way for the development of quantum rotor gyroscopes.

关键词： particles rotational angular

Influence of High-Density Bedding Plane Characteristics on Hydraulic Fracture Propagation in Shale Oil Reservoir

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第9期140卷 3051-3071页

作者： xiao yan Di Wang Haitao Yu State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Beijing102206China State Energy Center for Shale Oil Research and Development Beijing102206China Department of Geotechnical Engineering College of Civil Engineering Tongji UniversityShanghai200092China Petroleum Exploration and Production Research Institute SINOPECBeijing102206China Key Laboratory of Deep Earth Science and Engineering(Sichuan University) Ministry of EducationChengdu610065China

The existence of high-density bedding planes is a typical characteristic of shale oil *** the behavior of hydraulic fracturing in high-density laminated rocks is significant for promoting shale oil *** this study,a hydraulic fracturing model considering tensile failure and frictional slip of the bedding planes is established within the framework of the unified pipe-interface element method(UP-IEM).The model developed for simulating the interaction between the hydraulic fracture and the bedding plane is validated by comparison with experimental *** hydraulic fracturing patterns in sealed and unsealed bedding planes are ***,the effects of differential stress,bedding plane permeability,spacing,and the friction coefficient of the bedding plane are *** results showed that a single main fracture crossing the bedding planes is more likely to form in sealed bedding planes under high differential *** decrease in bedding plane permeability and the increase in the friction coefficient also promote the fracture propagating perpendicular to the bedding *** with high-density bedding planes has a poorer fracturing effect than that with low-density bedding planes,as the hydraulic fracture is prone to initiate and propagate along the bedding ***,higher injection pressure is needed to maintain fracture propagation along the *** increase in bedding density will lead to a smaller fracturing *** fluid seepage into the bedding planes slows shale *** is recommended that increasing the injection flow rate,selecting alternative fracturing fluids,and employing multi-well/multi-cluster fracturing may be efficient methods to improve energy production in shale oil reservoirs.

关键词： Hydraulic fracturing bedding planes shale unified pipe-interface element method

Methanol steam reforming for hydrogen production driven by an atomically precise Cu catalyst

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第7期9卷 1079-1084页

作者： Weigang Hu Haoqi Liu Yuankun Zhang Jiawei Ji Guangjun Li xiao Cai Xu Liu Wen wu Xu Weiping Ding yan Zhu School of Chemistry and Chemical Engineering Nanjing UniversityNanjing210093China School of Physical Science and Technology Ningbo UniversityNingbo315211China

Plasmon-induced hot-electron transfer from metal nanostructures is being intensely pursed in current photocatalytic research,however it remains elusive whether molecular-like metal clusters with excitonic behavior can be used as light-harvesting materials in solar energy utilization such as photocatalytic methanol steam *** this work,we report an atomically precise Cu_(13)cluster protected by dual ligands of thiolate and phosphine that can be viewed as the assembly of one top Cu atom and three Cu_(4)*** Cu_(13)H_(10)(SR)_(3)(PR’_(3))_(7)(SR=2,4-dichlorobenzenethiol,PR’_(3)=P(4-FC_(6)H_(4))_(3))cluster can give rise to highly efficient light-driven activity for methanol steam reforming toward H_(2)production.

关键词： Nanocluster Photocatalysis Methanol steam reforming Atomically precise Copper catalyst

小学生筛查性近视与主要带养人报告近视的差异研究

在线全文

学校读者我要写书评

暂无评论

中国健康教育 2024年第6期40卷 493-498页

作者：张向林李婷婷高振珊曹钰璇黄思哲陶舒曼伍晓艳许韶君陶芳标安徽医科大学公共卫生学院儿少卫生与妇幼保健学系安徽合肥230032 中山市中小学卫生保健所广东中山528403 出生人口健康教育部重点实验室/环境与人口健康安徽省重点实验室安徽合肥巴230032

目的分析中山市1~3年级小学生的近视现况、其与主要带养人报告近视的差异,并探索影响报告差异的主要因素,为儿童青少年早期近视的预防控制提供科学依据。方法于2023年5-7月,采用多阶段分层整群随机抽样方法抽取广东省中山市部分小学生... 详细信息

目的分析中山市1~3年级小学生的近视现况、其与主要带养人报告近视的差异,并探索影响报告差异的主要因素,为儿童青少年早期近视的预防控制提供科学依据。方法于2023年5-7月,采用多阶段分层整群随机抽样方法抽取广东省中山市部分小学生进行问卷调查和视力检查。采用χ^(2)检验分析筛查性近视和报告近视的差异,采用二元Logistic回归模型分析影响近视结果报告一致性的因素。结果中山市1~3年级学生总体筛查性近视率为25.3%,父母报告显示1~3年级小学生总体近视率为12.1%,父母总体知晓率为81.1%。二元Logistic回归分析结果显示,以1年级为参照,3年级的报告一致率较高,OR值为1.453(95%CI:1.160~1.819);以眼健康素养评分不良为参照,评分一般和评分良好的报告一致率较高,OR值分别为0.524(95%CI:0.423~0.649)和0.379(95%CI:0.293~0.467);以未进行过散瞳验光组为参照,进行过散瞳验光组的报告一致率较高,OR值为0.615(95%CI:0.455~0.831);以父母双方近视为参照,父母双方均不近视的报告一致率较高,OR值为0.669(95%CI:0.514~0.872);以母亲文化程度为小学及以下为参照,母亲文化程度为初中、高中及中专和大专及以上的报告一致率较高,OR值分别为0.514(95%CI:0.322~0.821)、0.355(95%CI:0.222~0.567)和0.313(95%CI:0.195~0.503)。结论眼健康素养评分良好和进行过散瞳验光是影响报告一致性的主要因素,因此未来应加强对父母近视防控的健康教育,提高父母对孩子近视状况的知晓度和报告准确性。

关键词：小学生近视眼健康行为评分一致性