检索结果-南通市图书馆

Experimental Investigation on Vertical Hydraulic Transport of Ores in Deepsea Mining

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

China Ocean Engineering 2024年第1期38卷 42-53页

作者： liU Lei liU Jian-cheng li xin XU li-xin ZHANG Xiu-zhan State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Sanya Yazhou Bay Institution of Deep-sea Sci-Tech Shanghai Jiao Tong UniversitySanya 572000China China Merchants Marine And Offshore Research Institute Co. Ltd.Shenzhen 518067China China Merchants Deepsea Research Institute(Sanya)Co. Ltd.Sanya 572000China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.

关键词： deepsea mining vertical hydraulic transport experiment flow characteristics

Height and body mass index trajectories from 1975 to 2015 and prevalence of stunting,underweight and obesity in 2016 among children in Chinese cities:findings from five rounds of a national survey

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第4期20卷 404-412页

作者： xin‑Nan Zong Hui li Ya‑Qin Zhang Department of Growth and Development Capital Institute of PediatricsBeijing 100020China

Background A more comprehensive assessment of growth and nutrition in children is required in China due to rapid socioeconomic processes.We aimed to investigate height and body mass index(BMI)trajectories from 1975 to 2015 and the prevalence of stunting and obesity in 2016 among children in Chinese cities.Methods A total of 904,263 children from birth to 6.9 years were collected from a series of nationally representative surveys in China.Height and BMI trajectories and prevalence of stunting,underweight,overweight and obesity were assessed.Results The average height level of Chinese urban children under 7 years presented a positive secular trend from 1975 to 2015;however,a slowing tendency occurred in 2005‒2015.An apparent increase was observed at the 5th,50th and 95th percentiles of BMI in urban children aged 3 years and older,with a more prominent increase at the 95th percentile.The total prevalence of stunting and underweight under 7 years was 1.4%and 2.0%,respectively.The total prevalence of overweight and obesity under 7 years was 12.6%and 4.3%,respectively,with 12.7%and 4.9%for boys,12.6%and 3.6%for girls,12.1%and 4.0%in urban areas and 13.1%and 4.5%in suburban rural areas.Conclusions The average height level of Chinese urban children has reached World Health Organization child growth standards since 2005 and presented a slowing tendency in secular trend in 2005‒2015.More attention and efforts and public health interventions should be urgently made to combat overweight and obesity among preschool children.

关键词： Body mass index Children Height Obesity Stunting

Strong Edge Coloring of Outerplane Graphs with Independent Crossings

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

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 467-477页

作者： Ke-Jie li xin ZHANG School of Mathematics and Statistics Xidian UniversityXi’an 710071China

The strong chromatic index of a graph is the minimum number of colors needed in a proper edge coloring so that no edge is adjacent to two edges of the same color.An outerplane graph with independent crossings is a graph embedded in the plane in such a way that all vertices are on the outer face and two pairs of crossing edges share no common end vertex.It is proved that every outerplane graph with independent crossings and maximum degreeΔhas strong chromatic index at most 4Δ-6 if Δ≥4,and at most 8 ifΔ≤3.Both bounds are sharp.

关键词： outer-1-planar graph IC-planar graph strong edge coloring crossing

Parametric study on contact sensors for MASW measurement-based interfacial debonding detection for SCCS

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第2期23卷 331-344页

作者： Chen Hongbing Pang xin Gan Shiyu li Yuanyuan Gokarna Chalise Nie xin Research Institute of Urbanization and Urban Safety School of Civil and Resource EngineeringUniversity of Science and Technology BeijingBeijing 100083China Department of Civil Engineering Tsinghua UniversityBeijing 100084China Faculty of Infrastructure Engineering Dalian University of TechnologyDalian 116081China

Steel-concrete composite structures(SCCS)have been widely used as primary load-bearing components in large-scale civil infrastructures.As the basis of the co-working ability of steel plate and concrete,the bonding status plays an essential role in guaranteeing the structural performance of SCCS.Accordingly,efficient non-destructive testing(NDT)on interfacial debondings in SCCS has become a prominent research area.Multi-channel analysis of surface waves(MASW)has been validated as an effective NDT technique for interfacial debonding detection for SCCS.However,the feasibility of MASW must be validated using experimental measurements.This study establishes a high-frequency data synchronous acquisition system with 32 channels to perform comparative verification experiments in depth.First,the current sensing approaches for high-frequency vibration and stress waves are summarized.Secondly,three types of contact sensors,namely,piezoelectric lead-zirconate-titanate(PZT)patches,accelerometers,and ultrasonic transducers,are selected for MASW measurement.Then,the selection and optimization of the force hammer head are performed.Comparative experiments are carried out for the optimal selection of ultrasonic transducers,PZT patches,and accelerometers for MASW measurement.In addition,the influence of different pasting methods on the output signal of the sensor array is discussed.Experimental results indicate that optimized PZT patches,acceleration sensors,and ultrasonic transducers can provide efficient data acquisition for MASW-based non-destructive experiments.The research findings in this study lay a solid foundation for analyzing the recognition accuracy of contact MASW measurement using different sensor arrays.

关键词： steel-concrete composite structures(SCCS) interface debonding detection multi-channel analysis of surface waves(MASW) sensor selection comparative experimental study

Hybrid model for BOF oxygen blowing time prediction based on oxygen balance mechanism and deep neural network

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 106-117页

作者： xin Shao Qing liu Zicheng xin Jiangshan Zhang Tao Zhou Shaoshuai li State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Engineering Research Center of MES Technology for Iron&Steel Production Ministry of EducationBeijing 100083China Laiwu Iron and Steel Group Yinshan Section Steel Co. Ltd.Jinan 271104China

The amount of oxygen blown into the converter is one of the key parameters for the control of the converter blowing process,which directly affects the tap-to-tap time of converter. In this study, a hybrid model based on oxygen balance mechanism (OBM) and deep neural network (DNN) was established for predicting oxygen blowing time in converter. A three-step method was utilized in the hybrid model. First, the oxygen consumption volume was predicted by the OBM model and DNN model, respectively. Second, a more accurate oxygen consumption volume was obtained by integrating the OBM model and DNN model. Finally, the converter oxygen blowing time was calculated according to the oxygen consumption volume and the oxygen supply intensity of each heat. The proposed hybrid model was verified using the actual data collected from an integrated steel plant in China, and compared with multiple linear regression model, OBM model, and neural network model including extreme learning machine, back propagation neural network, and DNN. The test results indicate that the hybrid model with a network structure of 3 hidden layer layers, 32-16-8 neurons per hidden layer, and 0.1 learning rate has the best prediction accuracy and stronger generalization ability compared with other models. The predicted hit ratio of oxygen consumption volume within the error±300 m^(3)is 96.67%;determination coefficient (R^(2)) and root mean square error (RMSE) are0.6984 and 150.03 m^(3), respectively. The oxygen blow time prediction hit ratio within the error±0.6 min is 89.50%;R2and RMSE are0.9486 and 0.3592 min, respectively. As a result, the proposed model can effectively predict the oxygen consumption volume and oxygen blowing time in the converter.

关键词： basic oxygen furnace oxygen consumption oxygen blowing time oxygen balance mechanism deep neural network hybrid model

Comparison of tailpipe carbonyls and volatile organic compounds emissions from in-use gasoline/CNG bi-fuel vehicles

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第1期135卷 619-629页

作者： Jiachen li Yunshan Ge xin Wang Mengzhu Zhang Haohao Wang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China

Ground-level ozone contamination has been globally an urban air quality issue,particularly for China,which has recently made significant progress in purifying its sky.Unregulated exhaust emissions from motor vehicles,predominantly carbonyls and volatile organic compounds(VOCs),are among the leading contributors to ozone formation.In this chassislevel study,the unregulated emissions from five China-5 certified gasoline/CNG bi-fuel taxis,along with their ozone forming potential(OFP),were evaluated.It is found that carbonyls and VOCs were mainly emitted during the starting phase no matter the engine was cold or hot.Compared to gasoline,CNG fueling reduced VOCs emissions on a large scale,especially in the starting phase,but had elevated carbonyls.On a fleet average,CNG fueling derived 15%and 46%less OFP than gasoline in cold-and hot-start tests,respectively.VOCs contributed to over 90%of the total OFP of the exhaust.In terms of alleviating ground-level ozone contamination,CNG is a feasible alternative to gasoline on light-duty vehicles.

关键词： CNG Gasoline Carbonyls VOCs OFP

Quantum self-attention neural networks for text classification

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第4期67卷 301-313页

作者： Guangxi li Xuanqiang ZHAO xin WANG Institute for Quantum Computing Baidu Research Centre for Quantum Software and Information University of Technology Sydney QICI Quantum Information and Computation Initiative Department of Computer ScienceThe University of Hong Kong Thrust of Artificial Intelligence Information HubHong Kong University of Science and Technology(Guangzhou)

An emerging direction of quantum computing is to establish meaningful quantum applications in various fields of artificial intelligence, including natural language processing(NLP). Although some efforts based on syntactic analysis have opened the door to research in quantum NLP(QNLP), limitations such as heavy syntactic preprocessing and syntax-dependent network architecture make them impracticable on larger and real-world data sets. In this paper, we propose a new simple network architecture, called the quantum selfattention neural network(QSANN), which can compensate for these limitations. Specifically, we introduce the self-attention mechanism into quantum neural networks and then utilize a Gaussian projected quantum self-attention serving as a sensible quantum version of self-attention. As a result, QSANN is effective and scalable on larger data sets and has the desirable property of being implementable on near-term quantum devices. In particular, our QSANN outperforms the best existing QNLP model based on syntactic analysis as well as a simple classical self-attention neural network in numerical experiments of text classification tasks on public data sets. We further show that our method exhibits robustness to low-level quantum noises and showcases resilience to quantum neural network architectures.

关键词： quantum neural networks self-attention natural language processing text classification parameterized quantum circuits

Upgraded durian genome reveals the role of chromosome reshuffling during ancestral karyotype evolution,lignin biosynthesis regulation,and stress tolerance

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(life Sciences) 2024年第6期67卷 1266-1279页

作者： Wanwan li xin Chen Jianing Yu Yuxian Zhu College of life Sciences Shaanxi Normal UniversityXi’an 710119China The State Key Laboratory of Protein and Gene Research College of Life SciencesPeking UniversityBeijing 100871China The Institute for Advanced Studies Wuhan UniversityWuhan 430072China

Durian(Durio zibethinus)is a tropical fruit that has a unique flavor and aroma.It occupies a significant phylogenetic position within the Malvaceae family.Extant core-eudicot plants are reported to share seven ancestral karyotypes that have undergone reshuffling,resulting in an abundant genomic diversity.However,the ancestral karyotypes of the Malvaceae family,as well as the evolution trajectory leading to the28 chromosomes in durian,remain poorly understood.Here,we report the high-quality assembly of the durian genome with comprehensive comparative genomic analyses.By analyzing the collinear blocks between cacao and durian,we inferred 11 Malvaceae ancestral karyotypes.These blocks were present in a single-copy form in cacao and mainly in triplicates in durian,possibly resulting from a recent whole genome triplication(WGT)event that led to hexaploidization of the durian genome around 20(17–24)million years ago.A large proportion of the duplicated genes in durian,such as those involved in the lignin biosynthesis module for phenylpropane biosynthesis,are derived directly from whole genome duplication,which makes it an important force in reshaping its genomic architecture.Transcriptome studies have revealed that genes involved in feruloyl-Co A formations were highly preferentially expressed in fruit peels,indicating that the thorns produced on durian fruit may comprise guaiacyl and syringyl lignins.Among all the analyzed transcription factors(TFs),members of the heat shock factor family(HSF)were the most significantly upregulated under heat stress.All subfamilies of genes encoding heat shock proteins(HSPs)in the durian genome appear to have undergone expansion.The potential interactions between HSF Dzi05.397 and HSPs were examined and experimentally verified.Our study provides a high-quality durian genome and reveals the reshuffling mechanism of ancestral Malvaceae chromosomes to produce the durian genome.We also provide insights into the mechanism underlying lignin biosynthesis and heat stress tolerance.

关键词： Durio zibethinus whole genome duplication whole genome triplication Malvaceae ancestral karyotypes chromosome reshuffling lignin biosynthesis heat stress

Protective Effects of Phellodendron Species on Bone Health: A Novel Perspective on Their Potentials in Treating Osteoporosis and Osteoarthritis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第4期30卷 379-384页

作者： xin li TAN Guo-yao ZHANG Qiang ZHANG Qun Good Clinical Practice Development Guangdong Provincial Key Laboratory of Bone and Joint Degeneration DiseasesThe Third Affiliated Hospital of Southern Medical UniversityGuangzhou(510630)China Department of Pharmacy Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhou(510120)China

Phellodendron(PN)species,traditionally used in Chinese medicine for centuries,hold promise as a potential treatment for osteoporosis(OP)and osteoarthritis(OA)due to their bioactive compounds.The bioactive compounds,including berberine and palmatine,exhibit anti-inflammatory,antioxidant,and bone-protective properties,contributing to their potential therapeutic benefits in promoting bone health and preventing bone loss.However,challenges such as the need for standardized preparation and dosing,limited clinical studies,and potential interactions with other medications hinder their clinical use.Nonetheless,the rich history of PN species in Chinese medicine provides a promising foundation for future investigation into their potential as alternative treatments for OP and OA.Further research is needed to fully understand the underlying mechanisms of action and explore the clinical implications of PN for bone health.

关键词： Phellodendron species bone health osteoporosis osteoarthritis review